P3Y11000000071000005300000P95DP4Y330.9false--12-31FY20190000764065003500000022000000280000010000000.0400.050.270.1250.1256000000006000000003018867943018867942926115692700840050.1000.100128000000.05750.06250.35000.10000.350010000010000058000000.7006500000248000004500000004500000000000P15YP45YP20YP45YP45YP3YP10YP3YP20YP10YP45Y927522531802789024800000 0000764065 2019-01-01 2019-12-31 0000764065 2018-01-01 2018-12-31 0000764065 2017-01-01 2017-12-31 0000764065 2019-06-28 0000764065 2020-02-18 0000764065 2018-12-31 0000764065 2019-12-31 0000764065 clf:AdjustedEBITDACalculationMember 2018-01-01 2018-12-31 0000764065 clf:AdjustedEBITDACalculationMember 2019-01-01 2019-12-31 0000764065 2016-12-31 0000764065 2017-12-31 0000764065 us-gaap:AdditionalPaidInCapitalMember 2017-01-01 2017-12-31 0000764065 us-gaap:NoncontrollingInterestMember 2017-01-01 2017-12-31 0000764065 us-gaap:RetainedEarningsMember 2018-01-01 2018-12-31 0000764065 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-12-31 0000764065 us-gaap:RetainedEarningsMember 2017-01-01 2017-12-31 0000764065 us-gaap:NoncontrollingInterestMember 2019-12-31 0000764065 us-gaap:AdditionalPaidInCapitalMember 2019-12-31 0000764065 us-gaap:CommonStockMember 2017-12-31 0000764065 us-gaap:AociAttributableToNoncontrollingInterestMember 2017-01-01 2017-12-31 0000764065 us-gaap:AdditionalPaidInCapitalMember 2018-01-01 2018-12-31 0000764065 us-gaap:TreasuryStockMember 2017-12-31 0000764065 us-gaap:CommonStockMember 2016-12-31 0000764065 us-gaap:NoncontrollingInterestMember 2018-12-31 0000764065 us-gaap:TreasuryStockMember 2016-12-31 0000764065 us-gaap:TreasuryStockMember 2019-01-01 2019-12-31 0000764065 us-gaap:CommonStockMember 2017-01-01 2017-12-31 0000764065 us-gaap:TreasuryStockMember 2017-01-01 2017-12-31 0000764065 us-gaap:RetainedEarningsMember 2018-12-31 0000764065 us-gaap:CommonStockMember 2019-01-01 2019-12-31 0000764065 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2018-01-01 2018-12-31 0000764065 us-gaap:AdditionalPaidInCapitalMember 2017-12-31 0000764065 us-gaap:CommonStockMember 2018-01-01 2018-12-31 0000764065 us-gaap:RetainedEarningsMember 2016-12-31 0000764065 us-gaap:CommonStockMember 2019-12-31 0000764065 us-gaap:TreasuryStockMember 2018-01-01 2018-12-31 0000764065 us-gaap:TreasuryStockMember 2019-12-31 0000764065 us-gaap:NoncontrollingInterestMember 2018-01-01 2018-12-31 0000764065 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2016-12-31 0000764065 us-gaap:TreasuryStockMember 2018-12-31 0000764065 us-gaap:AdditionalPaidInCapitalMember 2018-12-31 0000764065 us-gaap:RetainedEarningsMember 2019-12-31 0000764065 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2018-12-31 0000764065 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2017-12-31 0000764065 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2017-01-01 2017-12-31 0000764065 us-gaap:NoncontrollingInterestMember 2016-12-31 0000764065 us-gaap:CommonStockMember 2018-12-31 0000764065 us-gaap:NoncontrollingInterestMember 2019-01-01 2019-12-31 0000764065 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-01-01 2019-12-31 0000764065 us-gaap:RetainedEarningsMember 2019-01-01 2019-12-31 0000764065 us-gaap:RetainedEarningsMember 2017-12-31 0000764065 us-gaap:AdditionalPaidInCapitalMember 2016-12-31 0000764065 us-gaap:AdditionalPaidInCapitalMember 2019-01-01 2019-12-31 0000764065 us-gaap:NoncontrollingInterestMember 2017-12-31 0000764065 clf:MiningandPelletizingMember 2018-12-31 0000764065 clf:EmpireMember us-gaap:OtherCurrentLiabilitiesMember 2018-12-31 0000764065 clf:EmpireMember 2019-12-31 0000764065 clf:HibbingMember us-gaap:OtherNoncurrentLiabilitiesMember 2019-12-31 0000764065 clf:TildenMember 2017-01-01 2017-12-31 0000764065 clf:EmpireMember 2017-01-01 2017-12-31 0000764065 clf:HibbingMember us-gaap:OtherNoncurrentLiabilitiesMember 2018-12-31 0000764065 us-gaap:DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member 2018-01-01 2018-12-31 0000764065 clf:TildenMember 2017-01-01 2017-12-31 0000764065 clf:MiningandPelletizingMember 2017-12-31 0000764065 clf:TildenMember 2019-12-31 0000764065 us-gaap:SalesMember 2017-01-01 2017-12-31 0000764065 us-gaap:DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member 2018-01-01 0000764065 clf:MiningandPelletizingMember 2019-12-31 0000764065 clf:HibbingMember 2019-12-31 0000764065 clf:EmpireMember 2017-01-01 2017-12-31 0000764065 us-gaap:BuildingMember 2019-01-01 2019-12-31 0000764065 srt:MaximumMember us-gaap:ElectricGenerationEquipmentMember 2019-01-01 2019-12-31 0000764065 srt:MaximumMember us-gaap:LandImprovementsMember 2019-01-01 2019-12-31 0000764065 srt:MinimumMember us-gaap:EquipmentMember 2019-01-01 2019-12-31 0000764065 srt:MinimumMember us-gaap:ComputerEquipmentMember 2019-01-01 2019-12-31 0000764065 srt:MaximumMember us-gaap:EquipmentMember 2019-01-01 2019-12-31 0000764065 srt:MinimumMember us-gaap:OtherMachineryAndEquipmentMember 2019-01-01 2019-12-31 0000764065 srt:MinimumMember us-gaap:LandImprovementsMember 2019-01-01 2019-12-31 0000764065 srt:MaximumMember us-gaap:ComputerEquipmentMember 2019-01-01 2019-12-31 0000764065 srt:MinimumMember us-gaap:ElectricGenerationEquipmentMember 2019-01-01 2019-12-31 0000764065 srt:MaximumMember us-gaap:OtherMachineryAndEquipmentMember 2019-01-01 2019-12-31 0000764065 us-gaap:CargoAndFreightMember 2019-01-01 2019-12-31 0000764065 us-gaap:ProductMember 2018-01-01 2018-12-31 0000764065 us-gaap:CargoAndFreightMember 2017-01-01 2017-12-31 0000764065 clf:VenturepartnerscostreimbursementsMember 2018-01-01 2018-12-31 0000764065 clf:VenturepartnerscostreimbursementsMember 2017-01-01 2017-12-31 0000764065 us-gaap:CargoAndFreightMember 2018-01-01 2018-12-31 0000764065 us-gaap:ProductMember 2017-01-01 2017-12-31 0000764065 clf:VenturepartnerscostreimbursementsMember 2019-01-01 2019-12-31 0000764065 us-gaap:ProductMember 2019-01-01 2019-12-31 0000764065 us-gaap:OtherCurrentLiabilitiesMember 2019-12-31 0000764065 us-gaap:OtherCurrentLiabilitiesMember 2019-01-01 2019-12-31 0000764065 us-gaap:OtherCurrentLiabilitiesMember 2018-01-01 2018-12-31 0000764065 us-gaap:OtherCurrentLiabilitiesMember 2018-01-01 0000764065 us-gaap:OtherCurrentLiabilitiesMember 2018-12-31 0000764065 us-gaap:OtherNoncurrentLiabilitiesMember 2018-12-31 0000764065 us-gaap:OtherNoncurrentLiabilitiesMember 2019-12-31 0000764065 us-gaap:OtherNoncurrentLiabilitiesMember 2018-01-01 2018-12-31 0000764065 us-gaap:OtherNoncurrentLiabilitiesMember 2019-01-01 2019-12-31 0000764065 us-gaap:OtherNoncurrentLiabilitiesMember 2018-01-01 0000764065 us-gaap:OtherCurrentLiabilitiesMember clf:TakeOrPayContractsMember 2018-12-31 0000764065 2019-10-01 2019-12-31 0000764065 us-gaap:OtherCurrentLiabilitiesMember clf:TakeOrPayContractsMember 2019-12-31 0000764065 clf:OtherCountriesMember 2017-01-01 2017-12-31 0000764065 country:US 2018-12-31 0000764065 country:US 2017-12-31 0000764065 country:US 2019-01-01 2019-12-31 0000764065 country:CA 2017-01-01 2017-12-31 0000764065 country:US 2018-01-01 2018-12-31 0000764065 clf:OtherCountriesMember 2018-01-01 2018-12-31 0000764065 clf:OtherCountriesMember 2019-01-01 2019-12-31 0000764065 country:CA 2018-01-01 2018-12-31 0000764065 country:US 2019-12-31 0000764065 country:US 2017-01-01 2017-12-31 0000764065 country:CA 2019-01-01 2019-12-31 0000764065 us-gaap:CorporateMember 2019-12-31 0000764065 us-gaap:CorporateMember 2017-12-31 0000764065 us-gaap:OperatingSegmentsMember 2017-12-31 0000764065 clf:MetallicsMember 2017-12-31 0000764065 clf:MetallicsMember 2018-12-31 0000764065 clf:MetallicsMember 2019-12-31 0000764065 us-gaap:OperatingSegmentsMember 2018-12-31 0000764065 us-gaap:SegmentDiscontinuedOperationsMember 2018-12-31 0000764065 us-gaap:OperatingSegmentsMember 2019-12-31 0000764065 us-gaap:SegmentDiscontinuedOperationsMember 2019-12-31 0000764065 us-gaap:SegmentDiscontinuedOperationsMember 2017-12-31 0000764065 us-gaap:CorporateMember 2018-12-31 0000764065 clf:MiningandPelletizingMember 2019-01-01 2019-12-31 0000764065 clf:CorporateandOtherSegmentsMember 2017-01-01 2017-12-31 0000764065 clf:MetallicsMember 2018-01-01 2018-12-31 0000764065 clf:MiningandPelletizingMember 2018-01-01 2018-12-31 0000764065 clf:MetallicsMember 2019-01-01 2019-12-31 0000764065 clf:MiningandPelletizingMember 2017-01-01 2017-12-31 0000764065 clf:MetallicsMember 2017-01-01 2017-12-31 0000764065 clf:CorporateandOtherSegmentsMember 2018-01-01 2018-12-31 0000764065 clf:CorporateandOtherSegmentsMember 2019-01-01 2019-12-31 0000764065 us-gaap:IntersegmentEliminationMember clf:MetallicsMember 2019-01-01 2019-12-31 0000764065 us-gaap:OperatingSegmentsMember clf:MetallicsMember 2019-01-01 2019-12-31 0000764065 us-gaap:OperatingSegmentsMember clf:MiningandPelletizingMember 2019-01-01 2019-12-31 0000764065 us-gaap:IntersegmentEliminationMember clf:MiningandPelletizingMember 2019-01-01 2019-12-31 0000764065 us-gaap:OperatingSegmentsMember 2019-01-01 2019-12-31 0000764065 us-gaap:IntersegmentEliminationMember 2019-01-01 2019-12-31 0000764065 us-gaap:SalesRevenueNetMember us-gaap:CustomerConcentrationRiskMember 2018-01-01 2018-12-31 0000764065 us-gaap:SalesRevenueNetMember us-gaap:CustomerConcentrationRiskMember 2019-01-01 2019-12-31 0000764065 us-gaap:SalesRevenueNetMember us-gaap:CustomerConcentrationRiskMember 2017-01-01 2017-12-31 0000764065 clf:AdjustedEBITDACalculationMember 2017-01-01 2017-12-31 0000764065 clf:EBITDACalculationMember 2018-01-01 2018-12-31 0000764065 clf:EBITDACalculationMember 2019-01-01 2019-12-31 0000764065 clf:EBITDACalculationMember 2017-01-01 2017-12-31 0000764065 us-gaap:BuildingMember 2018-12-31 0000764065 us-gaap:MiningPropertiesAndMineralRightsMember 2018-12-31 0000764065 us-gaap:OtherMachineryAndEquipmentMember 2018-12-31 0000764065 us-gaap:MiningPropertiesAndMineralRightsMember 2019-12-31 0000764065 us-gaap:LandImprovementsMember 2018-12-31 0000764065 us-gaap:ConstructionInProgressMember 2019-12-31 0000764065 us-gaap:ElectricGenerationEquipmentMember 2018-12-31 0000764065 us-gaap:ComputerEquipmentMember 2018-12-31 0000764065 us-gaap:OtherAssetsMember 2018-12-31 0000764065 us-gaap:OtherAssetsMember 2019-12-31 0000764065 us-gaap:EquipmentMember 2019-12-31 0000764065 us-gaap:LandImprovementsMember 2019-12-31 0000764065 clf:AssetRetirementObligationMember 2018-12-31 0000764065 us-gaap:ConstructionInProgressMember 2018-12-31 0000764065 clf:AssetRetirementObligationMember 2019-12-31 0000764065 us-gaap:ElectricGenerationEquipmentMember 2019-12-31 0000764065 us-gaap:OtherMachineryAndEquipmentMember 2019-12-31 0000764065 us-gaap:ComputerEquipmentMember 2019-12-31 0000764065 us-gaap:BuildingMember 2019-12-31 0000764065 us-gaap:EquipmentMember 2018-12-31 0000764065 us-gaap:OtherNoncurrentAssetsMember 2019-12-31 0000764065 us-gaap:OtherNoncurrentAssetsMember 2018-12-31 0000764065 clf:A218.5Million8.0020201.5LienNotesMember 2017-01-01 2017-12-31 0000764065 clf:A540million8.252020FirstLienNotesMember 2017-01-01 2017-12-31 0000764065 clf:A500Million4.802020SeniorNotesMember 2017-01-01 2017-12-31 0000764065 clf:A544.2Million7.752020SecondLienNotesMember 2017-01-01 2017-12-31 0000764065 clf:A400million5.902020SeniorNotesMember 2017-01-01 2017-12-31 0000764065 clf:A700Million4.8752021SeniorNotesMember 2017-01-01 2017-12-31 0000764065 clf:A750Million5.8752027SeniorNotesMember 2019-12-31 0000764065 clf:A316.25Million1.502025SeniorNotesMember 2019-01-01 2019-12-31 0000764065 us-gaap:RevolvingCreditFacilityMember 2019-12-31 0000764065 clf:A1.075Billion5.752025SeniorNotesMember 2019-01-01 2019-12-31 0000764065 srt:MaximumMember clf:A316.25Million1.502025SeniorNotesMember 2019-01-01 2019-12-31 0000764065 clf:A800Million6.252040SeniorNotesMember 2019-12-31 0000764065 us-gaap:RevolvingCreditFacilityMember us-gaap:LondonInterbankOfferedRateLIBORMember 2019-01-01 2019-12-31 0000764065 srt:MinimumMember clf:A316.25Million1.502025SeniorNotesMember 2019-01-01 2019-12-31 0000764065 clf:A316.25Million1.502025SeniorNotesMember 2019-12-31 0000764065 clf:A800Million6.252040SeniorNotesMember 2019-01-01 2019-12-31 0000764065 us-gaap:RevolvingCreditFacilityMember clf:FederalFundsRateMember 2019-01-01 2019-12-31 0000764065 us-gaap:RevolvingCreditFacilityMember us-gaap:PrimeRateMember 2019-01-01 2019-12-31 0000764065 clf:A750Million5.8752027SeniorNotesMember 2019-01-01 2019-12-31 0000764065 srt:MaximumMember clf:A800Million6.252040SeniorNotesMember 2019-01-01 2019-12-31 0000764065 clf:A316.25Million1.502025SeniorNotesMember 2018-01-01 2018-12-31 0000764065 us-gaap:TrustForBenefitOfEmployeesMember 2019-01-01 2019-12-31 0000764065 us-gaap:EquityMember clf:A316.25Million1.502025SeniorNotesMember 2019-12-31 0000764065 clf:A400Million4.8752024SeniorNotesMember 2019-12-31 0000764065 clf:A400Million4.8752024SeniorNotesMember 2019-01-01 2019-12-31 0000764065 srt:MinimumMember clf:A800Million6.252040SeniorNotesMember 2019-01-01 2019-12-31 0000764065 us-gaap:RevolvingCreditFacilityMember 2019-01-01 2019-12-31 0000764065 clf:A750Million5.8752027SeniorNotesMember clf:DebtInstrumentRedemptionPeriodOneIncludingPremiumMember 2019-01-01 2019-12-31 0000764065 clf:A750Million5.8752027SeniorNotesMember us-gaap:DebtInstrumentRedemptionPeriodTwoMember 2019-01-01 2019-12-31 0000764065 clf:A750Million5.8752027SeniorNotesMember us-gaap:DebtInstrumentRedemptionPeriodThreeMember 2019-01-01 2019-12-31 0000764065 clf:A750Million5.8752027SeniorNotesMember us-gaap:DebtInstrumentRedemptionPeriodFourMember 2019-01-01 2019-12-31 0000764065 clf:A750Million5.8752027SeniorNotesMember us-gaap:DebtInstrumentRedemptionPeriodFiveMember 2019-01-01 2019-12-31 0000764065 clf:A750Million5.8752027SeniorNotesMember clf:DebtInstrumentRedemptionPeriodOneUponEquityIssuanceMember 2019-01-01 2019-12-31 0000764065 clf:A316.25Million1.502025SeniorNotesMember 2018-12-31 0000764065 clf:A400Million4.8752024SeniorNotesMember 2018-12-31 0000764065 clf:A1.075Billion5.752025SeniorNotesMember 2018-12-31 0000764065 clf:A700Million4.8752021SeniorNotesMember 2018-12-31 0000764065 us-gaap:RevolvingCreditFacilityMember 2018-12-31 0000764065 clf:A800Million6.252040SeniorNotesMember 2018-12-31 0000764065 clf:A700Million4.8752021SeniorNotesMember 2019-01-01 2019-12-31 0000764065 us-gaap:LetterOfCreditMember 2018-12-31 0000764065 us-gaap:LetterOfCreditMember 2019-12-31 0000764065 clf:A700Million4.8752021SeniorNotesMember 2018-01-01 2018-12-31 0000764065 clf:A400million5.902020SeniorNotesMember 2018-01-01 2018-12-31 0000764065 clf:A500Million4.802020SeniorNotesMember 2018-01-01 2018-12-31 0000764065 clf:A1.075Billion5.752025SeniorNotesMember 2018-01-01 2018-12-31 0000764065 clf:A400Million4.8752024SeniorNotesMember us-gaap:DebtInstrumentRedemptionPeriodFourMember 2019-01-01 2019-12-31 0000764065 clf:A400Million4.8752024SeniorNotesMember us-gaap:DebtInstrumentRedemptionPeriodThreeMember 2019-01-01 2019-12-31 0000764065 clf:A400Million4.8752024SeniorNotesMember clf:DebtInstrumentRedemptionPeriodOneIncludingPremiumMember 2019-01-01 2019-12-31 0000764065 clf:A400Million4.8752024SeniorNotesMember us-gaap:DebtInstrumentRedemptionPeriodOneMember 2019-01-01 2019-12-31 0000764065 clf:A400Million4.8752024SeniorNotesMember clf:DebtInstrumentRedemptionPeriodOneUponEquityIssuanceMember 2019-01-01 2019-12-31 0000764065 clf:A400Million4.8752024SeniorNotesMember us-gaap:DebtInstrumentRedemptionPeriodTwoMember 2019-01-01 2019-12-31 0000764065 clf:A1.075Billion5.752025SeniorNotesMember 2019-12-31 0000764065 clf:DerivativeAssetMember clf:CustomerSupplyAgreementMember us-gaap:FairValueInputsLevel3Member us-gaap:NondesignatedMember us-gaap:MarketApproachValuationTechniqueMember 2018-12-31 0000764065 clf:DerivativeAssetMember clf:ProvisionalPricingArrangementsMember us-gaap:FairValueInputsLevel3Member us-gaap:NondesignatedMember us-gaap:MarketApproachValuationTechniqueMember 2019-12-31 0000764065 clf:DerivativeAssetMember clf:CustomerSupplyAgreementMember us-gaap:FairValueInputsLevel3Member us-gaap:NondesignatedMember us-gaap:MarketApproachValuationTechniqueMember 2019-12-31 0000764065 clf:DerivativeAssetMember clf:ProvisionalPricingArrangementsMember us-gaap:FairValueInputsLevel3Member us-gaap:NondesignatedMember us-gaap:MarketApproachValuationTechniqueMember 2018-12-31 0000764065 us-gaap:OtherCurrentLiabilitiesMember clf:ProvisionalPricingArrangementsMember us-gaap:FairValueInputsLevel3Member us-gaap:NondesignatedMember us-gaap:MarketApproachValuationTechniqueMember 2019-12-31 0000764065 clf:A750Million5.8752027SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:SeniorNotesMember 2019-12-31 0000764065 clf:A750Million5.8752027SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:SeniorNotesMember 2018-12-31 0000764065 us-gaap:InterestRateSwapMember us-gaap:FairValueInputsLevel2Member us-gaap:CarryingReportedAmountFairValueDisclosureMember 2019-12-31 0000764065 us-gaap:RevolvingCreditFacilityMember us-gaap:FairValueInputsLevel2Member us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:LineOfCreditMember 2019-12-31 0000764065 us-gaap:InterestRateSwapMember us-gaap:FairValueInputsLevel2Member us-gaap:EstimateOfFairValueFairValueDisclosureMember 2019-12-31 0000764065 clf:A316.25Million1.502025SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:SeniorNotesMember 2019-12-31 0000764065 clf:A750Million5.8752027SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:SeniorNotesMember 2019-12-31 0000764065 us-gaap:RevolvingCreditFacilityMember us-gaap:FairValueInputsLevel2Member us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:LineOfCreditMember 2018-12-31 0000764065 us-gaap:RevolvingCreditFacilityMember us-gaap:FairValueInputsLevel2Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:LineOfCreditMember 2019-12-31 0000764065 clf:A800Million6.252040SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:SeniorNotesMember 2019-12-31 0000764065 clf:A1.075Billion5.752025SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:SeniorNotesMember 2018-12-31 0000764065 clf:A316.25Million1.502025SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:SeniorNotesMember 2019-12-31 0000764065 clf:A750Million5.8752027SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:SeniorNotesMember 2018-12-31 0000764065 clf:A400Million4.8752024SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:SeniorNotesMember 2018-12-31 0000764065 clf:A1.075Billion5.752025SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:SeniorNotesMember 2018-12-31 0000764065 us-gaap:InterestRateSwapMember us-gaap:FairValueInputsLevel2Member us-gaap:EstimateOfFairValueFairValueDisclosureMember 2018-12-31 0000764065 clf:A400Million4.8752024SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:SeniorNotesMember 2019-12-31 0000764065 clf:A700Million4.8752021SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:SeniorNotesMember 2019-12-31 0000764065 clf:A400Million4.8752024SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:SeniorNotesMember 2018-12-31 0000764065 clf:A700Million4.8752021SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:SeniorNotesMember 2018-12-31 0000764065 clf:A1.075Billion5.752025SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:SeniorNotesMember 2019-12-31 0000764065 us-gaap:InterestRateSwapMember us-gaap:FairValueInputsLevel2Member us-gaap:CarryingReportedAmountFairValueDisclosureMember 2018-12-31 0000764065 clf:A800Million6.252040SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:SeniorNotesMember 2019-12-31 0000764065 clf:A800Million6.252040SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:SeniorNotesMember 2018-12-31 0000764065 us-gaap:RevolvingCreditFacilityMember us-gaap:FairValueInputsLevel2Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:LineOfCreditMember 2018-12-31 0000764065 clf:A700Million4.8752021SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:SeniorNotesMember 2018-12-31 0000764065 us-gaap:CarryingReportedAmountFairValueDisclosureMember 2019-12-31 0000764065 clf:A800Million6.252040SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:SeniorNotesMember 2018-12-31 0000764065 clf:A316.25Million1.502025SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:SeniorNotesMember 2018-12-31 0000764065 us-gaap:CarryingReportedAmountFairValueDisclosureMember 2018-12-31 0000764065 clf:A400Million4.8752024SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:SeniorNotesMember 2019-12-31 0000764065 us-gaap:EstimateOfFairValueFairValueDisclosureMember 2018-12-31 0000764065 us-gaap:EstimateOfFairValueFairValueDisclosureMember 2019-12-31 0000764065 clf:A700Million4.8752021SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:SeniorNotesMember 2019-12-31 0000764065 clf:A316.25Million1.502025SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:SeniorNotesMember 2018-12-31 0000764065 clf:A1.075Billion5.752025SeniorNotesMember us-gaap:FairValueInputsLevel1Member us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:SeniorNotesMember 2019-12-31 0000764065 us-gaap:FairValueInputsLevel2Member 2018-12-31 0000764065 us-gaap:FairValueInputsLevel3Member 2018-12-31 0000764065 us-gaap:FairValueInputsLevel1Member 2018-12-31 0000764065 srt:WeightedAverageMember clf:DerivativeAssetMember clf:CustomerSupplyAgreementMember us-gaap:FairValueInputsLevel3Member us-gaap:NondesignatedMember clf:CustomersHotRolledSteelEstimateMember us-gaap:MarketApproachValuationTechniqueMember 2019-01-01 2019-12-31 0000764065 srt:WeightedAverageMember clf:DerivativeAssetMember clf:ProvisionalPricingArrangementsMember us-gaap:FairValueInputsLevel3Member us-gaap:NondesignatedMember clf:ManagementsEstimateOfSixtyTwoPercentMember us-gaap:MarketApproachValuationTechniqueMember 2019-01-01 2019-12-31 0000764065 srt:WeightedAverageMember us-gaap:OtherCurrentLiabilitiesMember clf:ProvisionalPricingArrangementsMember us-gaap:FairValueInputsLevel3Member us-gaap:NondesignatedMember clf:PPIEstimatesMember us-gaap:MarketApproachValuationTechniqueMember 2019-01-01 2019-12-31 0000764065 us-gaap:FairValueInputsLevel2Member 2019-12-31 0000764065 us-gaap:FairValueInputsLevel1Member 2019-12-31 0000764065 us-gaap:FairValueInputsLevel3Member 2019-12-31 0000764065 us-gaap:FairValueInputsLevel3Member 2017-12-31 0000764065 us-gaap:FairValueInputsLevel3Member 2019-01-01 2019-12-31 0000764065 us-gaap:FairValueInputsLevel3Member 2018-01-01 2018-12-31 0000764065 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 clf:GrossCompanyBenefitsMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ChangesinAssumptionsforDefinedBenefitPlansPerCapitaClaimsMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ChangesinAssumptionsforDefinedBenefitPlansActuarialGainLossMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ChangeinAssumptionsforDefinedBenefitPlansDiscountRatesMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ChangeinAssumptionsforDefinedBenefitPlansDiscountRatesMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ChangeinAssumptionsforDefinedBenefitPlansDiscountRatesMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ChangeinAssumptionsforDefinedBenefitPlansDiscountRatesMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ChangesinAssumptionsforDefinedBenefitPlansActuarialGainLossMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ChangesinAssumptionsforDefinedBenefitPlansOtherActuarialGainLossMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ChangesinAssumptionsforDefinedBenefitPlansOtherActuarialGainLossMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ChangesinAssumptionsforDefinedBenefitPlansMortalityMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ChangesinAssumptionsforDefinedBenefitPlansActuarialGainLossMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ChangesinAssumptionsforDefinedBenefitPlansActuarialGainLossMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ChangesinAssumptionsforDefinedBenefitPlansOtherActuarialGainLossMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ChangesinAssumptionsforDefinedBenefitPlansMortalityMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ChangeinAssumptionsforDefinedBenefitPlansDemographicMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ChangeinAssumptionsforDefinedBenefitPlansDemographicMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ChangesinAssumptionsforDefinedBenefitPlansPerCapitaClaimsMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ChangesinAssumptionsforDefinedBenefitPlansPerCapitaClaimsMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ChangesinAssumptionsforDefinedBenefitPlansMortalityMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ChangesinAssumptionsforDefinedBenefitPlansOtherActuarialGainLossMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ChangesinAssumptionsforDefinedBenefitPlansPerCapitaClaimsMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ChangeinAssumptionsforDefinedBenefitPlansDemographicMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ChangeinAssumptionsforDefinedBenefitPlansDemographicMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ChangesinAssumptionsforDefinedBenefitPlansMortalityMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:SalariedMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 clf:SERPDomain us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 clf:HourlyMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 clf:HourlyMember us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 clf:SERPDomain us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 clf:HourlyMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 clf:SalaryMember us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 clf:SalaryMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 clf:SalariedMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 clf:SalaryMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 clf:SalaryMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 clf:IronHourlyMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 clf:SalariedMember us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 clf:OreMiningMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 clf:IronHourlyMember us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 clf:SalariedMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 clf:HourlyMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 us-gaap:PensionPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:StructuredCreditMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2017-12-31 0000764065 us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2017-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:StructuredCreditMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2017-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2017-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2017-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 clf:StructuredCreditMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:CashMember us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:FixedIncomeInvestmentsMember us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesUsLargeCapMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:CashMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 clf:DefinedBenefitPlanEquitySecuritiesUSSmallandMidCapMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 clf:DefinedBenefitPlanEquitySecuritiesUSSmallandMidCapMember us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 clf:DefinedBenefitPlanEquitySecuritiesUSSmallandMidCapMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:FixedIncomeInvestmentsMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesUsLargeCapMember us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 clf:StructuredCreditMember us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:RealEstateMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:CashMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 clf:StructuredCreditMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesNonUsMember us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesNonUsMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesUsLargeCapMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:CashMember us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesNonUsMember us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesNonUsMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:FixedIncomeInvestmentsMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:FixedIncomeInvestmentsMember us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 clf:StructuredCreditMember us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesUsLargeCapMember us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 clf:DefinedBenefitPlanEquitySecuritiesUSSmallandMidCapMember us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel3Member 2019-01-01 2019-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel3Member 2019-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel3Member 2018-12-31 0000764065 us-gaap:StructuredFinanceMember us-gaap:FairValueInputsLevel3Member 2018-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel3Member 2019-01-01 2019-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel3Member 2019-01-01 2019-12-31 0000764065 us-gaap:StructuredFinanceMember us-gaap:FairValueInputsLevel3Member 2019-01-01 2019-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel3Member 2018-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel3Member 2019-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel3Member 2019-12-31 0000764065 us-gaap:StructuredFinanceMember us-gaap:FairValueInputsLevel3Member 2019-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel3Member 2018-12-31 0000764065 clf:PriorToAge65Member 2019-12-31 0000764065 us-gaap:RealEstateMember 2019-01-01 2019-12-31 0000764065 us-gaap:StructuredFinanceMember 2019-01-01 2019-12-31 0000764065 clf:IronHourlyMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel3Member 2018-01-01 2018-12-31 0000764065 us-gaap:StructuredFinanceMember us-gaap:FairValueInputsLevel3Member 2018-01-01 2018-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel3Member 2017-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel3Member 2018-01-01 2018-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel3Member 2018-01-01 2018-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel3Member 2017-12-31 0000764065 us-gaap:StructuredFinanceMember us-gaap:FairValueInputsLevel3Member 2017-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel3Member 2017-12-31 0000764065 clf:DirectPaymentsMember 2018-01-01 2018-12-31 0000764065 clf:VebaTrustMember 2019-12-31 0000764065 clf:DirectPaymentsMember 2019-01-01 2019-12-31 0000764065 clf:VebaTrustMember 2018-01-01 2018-12-31 0000764065 clf:DirectPaymentsMember 2019-12-31 0000764065 clf:VebaTrustMember 2019-01-01 2019-12-31 0000764065 clf:IronHourlyMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:RealEstateMember us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:CashMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:StructuredFinanceMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:RealEstateMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:CashMember us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:EquitySecuritiesMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:FixedIncomeInvestmentsMember us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:StructuredFinanceMember us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:EquitySecuritiesMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:StructuredFinanceMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:FixedIncomeInvestmentsMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:EquitySecuritiesMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:CashMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:EquitySecuritiesMember us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:StructuredFinanceMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:RealEstateMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:FixedIncomeInvestmentsMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 clf:DefinedBenefitPlanEquitySecuritiesUSSmallandMidCapMember us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 clf:StructuredCreditMember us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesUsLargeCapMember us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesUsLargeCapMember us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesNonUsMember us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:CashMember us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:FixedIncomeInvestmentsMember us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:CashMember us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesUsLargeCapMember us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesNonUsMember us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 clf:StructuredCreditMember us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 clf:DefinedBenefitPlanEquitySecuritiesUSSmallandMidCapMember us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:CashMember us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 clf:StructuredCreditMember us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:FixedIncomeInvestmentsMember us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesUsLargeCapMember us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 clf:StructuredCreditMember us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 clf:DefinedBenefitPlanEquitySecuritiesUSSmallandMidCapMember us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:FixedIncomeInvestmentsMember us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesNonUsMember us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesNonUsMember us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 clf:DefinedBenefitPlanEquitySecuritiesUSSmallandMidCapMember us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2017-12-31 0000764065 us-gaap:PensionPlansDefinedBenefitMember 2017-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:CashMember us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesUsLargeCapMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 clf:StructuredCreditMember us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:FixedIncomeInvestmentsMember us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 clf:AsiaPacificIronOreMember 2019-01-01 2019-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesNonUsMember us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:CashMember us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 clf:DefinedBenefitPlanEquitySecuritiesUSSmallandMidCapMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesUsLargeCapMember us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 clf:DefinedBenefitPlanEquitySecuritiesUSSmallandMidCapMember us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 clf:StructuredCreditMember us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesUsLargeCapMember us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 clf:DefinedBenefitPlanEquitySecuritiesUSSmallandMidCapMember us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:CashMember us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesNonUsMember us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 clf:StructuredCreditMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:FixedIncomeInvestmentsMember us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesUsLargeCapMember us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:FixedIncomeInvestmentsMember us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 clf:StructuredCreditMember us-gaap:FairValueInputsLevel3Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesNonUsMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 clf:DefinedBenefitPlanEquitySecuritiesUSSmallandMidCapMember us-gaap:FairValueInputsLevel2Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesNonUsMember us-gaap:FairValueInputsLevel1Member us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000764065 clf:ObligationDomain clf:SalariedMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:SalaryMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ObligationDomain clf:SalaryMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:InterestCostDomain clf:SalaryMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ServiceCostDomain clf:OreMiningDomain us-gaap:PensionPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:InterestCostDomain clf:OreMiningDomain us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:SalaryMember us-gaap:PensionPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:ServiceCostDomain clf:OreMiningDomain us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ServiceCostDomain clf:SalariedMember us-gaap:PensionPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:ObligationDomain clf:OreMiningDomain us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:HourlyMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:InterestCostDomain clf:SERPDomain us-gaap:PensionPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:HourlyMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ObligationDomain clf:SalariedMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ObligationDomain clf:HourlyMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:ServiceCostDomain clf:SalariedMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ServiceCostDomain clf:IronHourlyMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:InterestCostDomain clf:SERPDomain us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:InterestCostDomain clf:IronHourlyMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:InterestCostDomain clf:SalaryMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:ServiceCostDomain clf:HourlyMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ServiceCostDomain clf:IronHourlyMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ObligationDomain clf:HourlyMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:InterestCostDomain clf:SalaryMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ObligationDomain clf:SalariedMember us-gaap:PensionPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:ServiceCostDomain clf:SERPDomain us-gaap:PensionPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:ObligationDomain clf:SalaryMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:SalaryMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ObligationDomain clf:SERPDomain us-gaap:PensionPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:ServiceCostDomain clf:SalaryMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:InterestCostDomain clf:SalariedMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ObligationDomain clf:HourlyMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:InterestCostDomain clf:IronHourlyMember us-gaap:PensionPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:InterestCostDomain clf:HourlyMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:SalaryMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:InterestCostDomain clf:SERPDomain us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:InterestCostDomain clf:OreMiningDomain us-gaap:PensionPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:ServiceCostDomain clf:HourlyMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:InterestCostDomain clf:SalariedMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ServiceCostDomain clf:HourlyMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:ServiceCostDomain clf:SERPDomain us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:InterestCostDomain clf:SalariedMember us-gaap:PensionPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:SalaryMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ServiceCostDomain clf:SalaryMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ObligationDomain clf:OreMiningDomain us-gaap:PensionPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:ObligationDomain clf:IronHourlyMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ServiceCostDomain clf:SERPDomain us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ServiceCostDomain clf:SalaryMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ObligationDomain clf:SERPDomain us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:HourlyMember us-gaap:PensionPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:InterestCostDomain clf:HourlyMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:InterestCostDomain clf:HourlyMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:ObligationDomain clf:IronHourlyMember us-gaap:PensionPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:ObligationDomain clf:IronHourlyMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:ServiceCostDomain clf:SalariedMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ObligationDomain clf:SERPDomain us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:SalaryMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000764065 clf:InterestCostDomain clf:IronHourlyMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ObligationDomain clf:SalaryMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:ServiceCostDomain clf:IronHourlyMember us-gaap:PensionPlansDefinedBenefitMember 2017-01-01 2017-12-31 0000764065 clf:StructuredCreditMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-12-31 0000764065 clf:StructuredCreditMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 clf:DefinedBenefitPlanEquitySecuritiesUSSmallandMidCapMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:FixedIncomeInvestmentsMember us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesNonUsMember us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesUsLargeCapMember us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 clf:StructuredCreditMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:CashMember us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:CashMember us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:FixedIncomeInvestmentsMember us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 clf:StructuredCreditMember us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesUsLargeCapMember us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesNonUsMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesUsLargeCapMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 clf:DefinedBenefitPlanEquitySecuritiesUSSmallandMidCapMember us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:RealEstateMember us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:CashMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesNonUsMember us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:HedgeFundsMember us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 clf:StructuredCreditMember us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesUsLargeCapMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:FairValueInputsLevel2Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 clf:DefinedBenefitPlanEquitySecuritiesUSSmallandMidCapMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 clf:DefinedBenefitPlanEquitySecuritiesUSSmallandMidCapMember us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:FixedIncomeInvestmentsMember us-gaap:FairValueInputsLevel3Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:DefinedBenefitPlanEquitySecuritiesNonUsMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:PrivateEquityFundsMember us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 us-gaap:FairValueInputsLevel1Member us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-12-31 0000764065 2018-10-01 2018-10-01 0000764065 us-gaap:PerformanceSharesMember clf:AR2015EquityPlanMember 2019-01-01 2019-12-31 0000764065 us-gaap:RestrictedStockUnitsRSUMember clf:Amended2015EquityPlanDomain 2017-01-01 2017-12-31 0000764065 us-gaap:RestrictedStockUnitsRSUMember clf:AR2015EquityPlanMember 2017-01-01 2017-12-31 0000764065 us-gaap:RestrictedStockUnitsRSUMember clf:AR2015EquityPlanMember 2018-01-01 2018-12-31 0000764065 us-gaap:RestrictedStockUnitsRSUMember clf:AR2015EquityPlanMember 2019-01-01 2019-12-31 0000764065 us-gaap:PerformanceSharesMember clf:AR2015EquityPlanMember 2018-01-01 2018-12-31 0000764065 us-gaap:PerformanceSharesMember clf:AR2015EquityPlanMember 2017-01-01 2017-12-31 0000764065 us-gaap:PerformanceSharesMember clf:Amended2015EquityPlanDomain 2017-01-01 2017-12-31 0000764065 us-gaap:OperatingIncomeLossMember 2018-01-01 2018-12-31 0000764065 us-gaap:SellingGeneralAndAdministrativeExpensesMember 2017-01-01 2017-12-31 0000764065 us-gaap:StockCompensationPlanMember 2019-01-01 2019-12-31 0000764065 us-gaap:OperatingIncomeLossMember 2019-01-01 2019-12-31 0000764065 us-gaap:StockCompensationPlanMember 2017-01-01 2017-12-31 0000764065 us-gaap:CostOfSalesMember 2019-01-01 2019-12-31 0000764065 us-gaap:SellingGeneralAndAdministrativeExpensesMember 2018-01-01 2018-12-31 0000764065 us-gaap:CostOfSalesMember 2017-01-01 2017-12-31 0000764065 us-gaap:SellingGeneralAndAdministrativeExpensesMember 2019-01-01 2019-12-31 0000764065 us-gaap:OperatingIncomeLossMember 2017-01-01 2017-12-31 0000764065 us-gaap:StockCompensationPlanMember 2018-01-01 2018-12-31 0000764065 us-gaap:CostOfSalesMember 2018-01-01 2018-12-31 0000764065 srt:DirectorMember us-gaap:DeferredCompensationShareBasedPaymentsMember us-gaap:ShareBasedPaymentArrangementNonemployeeMember clf:DirectorsPlanMember 2019-01-01 2019-12-31 0000764065 srt:DirectorMember us-gaap:DeferredCompensationShareBasedPaymentsMember us-gaap:ShareBasedPaymentArrangementNonemployeeMember clf:DirectorsPlanMember 2017-01-01 2017-12-31 0000764065 srt:DirectorMember us-gaap:RestrictedStockUnitsRSUMember us-gaap:ShareBasedPaymentArrangementNonemployeeMember clf:DirectorsPlanMember 2018-01-01 2018-12-31 0000764065 srt:DirectorMember us-gaap:DeferredCompensationShareBasedPaymentsMember us-gaap:ShareBasedPaymentArrangementNonemployeeMember clf:DirectorsPlanMember 2018-01-01 2018-12-31 0000764065 srt:DirectorMember us-gaap:RestrictedStockUnitsRSUMember us-gaap:ShareBasedPaymentArrangementNonemployeeMember clf:DirectorsPlanMember 2017-01-01 2017-12-31 0000764065 srt:DirectorMember us-gaap:RestrictedStockUnitsRSUMember us-gaap:ShareBasedPaymentArrangementNonemployeeMember clf:DirectorsPlanMember 2019-01-01 2019-12-31 0000764065 2015-01-01 2015-03-31 0000764065 us-gaap:RestrictedStockUnitsRSUMember 2018-01-01 2018-12-31 0000764065 clf:DirectorsPlanMember 2018-04-25 2018-04-25 0000764065 clf:DirectorsPlanMember 2018-04-23 2018-04-23 0000764065 us-gaap:PerformanceSharesMember 2017-06-26 2017-06-26 0000764065 srt:MaximumMember us-gaap:PerformanceSharesMember 2019-01-01 2019-12-31 0000764065 2014-10-01 2014-12-31 0000764065 clf:CliffsNaturalResourceInc.2015EmployeeStockPurchasePlanMember 2019-12-31 0000764065 srt:MaximumMember clf:AR2015EquityPlanMember 2019-12-31 0000764065 us-gaap:PerformanceSharesMember 2019-01-01 2019-12-31 0000764065 us-gaap:PerformanceSharesMember 2017-02-21 2017-02-21 0000764065 srt:MinimumMember us-gaap:PerformanceSharesMember 2019-01-01 2019-12-31 0000764065 clf:DirectorsPlanMember 2019-01-01 2019-12-31 0000764065 us-gaap:RestrictedStockMember 2018-01-01 2018-12-31 0000764065 clf:DirectorsRetainerAndVoluntarySharesMember 2018-01-01 2018-12-31 0000764065 us-gaap:EmployeeStockOptionMember 2019-12-31 0000764065 us-gaap:RestrictedStockMember 2019-12-31 0000764065 us-gaap:EmployeeStockOptionMember 2018-12-31 0000764065 clf:DirectorsRetainerAndVoluntarySharesMember 2018-12-31 0000764065 us-gaap:PerformanceSharesMember 2017-01-01 2017-12-31 0000764065 clf:DirectorsRetainerAndVoluntarySharesMember 2017-12-31 0000764065 us-gaap:PerformanceSharesMember 2016-12-31 0000764065 us-gaap:RestrictedStockMember 2017-12-31 0000764065 us-gaap:RestrictedStockMember 2019-01-01 2019-12-31 0000764065 us-gaap:EmployeeStockOptionMember 2019-01-01 2019-12-31 0000764065 us-gaap:EmployeeStockOptionMember 2018-01-01 2018-12-31 0000764065 us-gaap:PerformanceSharesMember 2018-12-31 0000764065 clf:DirectorsRetainerAndVoluntarySharesMember 2019-01-01 2019-12-31 0000764065 us-gaap:EmployeeStockOptionMember 2017-12-31 0000764065 clf:DirectorsRetainerAndVoluntarySharesMember 2019-12-31 0000764065 us-gaap:PerformanceSharesMember 2017-12-31 0000764065 clf:DirectorsRetainerAndVoluntarySharesMember 2017-01-01 2017-12-31 0000764065 us-gaap:EmployeeStockOptionMember 2016-12-31 0000764065 us-gaap:RestrictedStockMember 2018-12-31 0000764065 us-gaap:PerformanceSharesMember 2018-01-01 2018-12-31 0000764065 clf:DirectorsRetainerAndVoluntarySharesMember 2016-12-31 0000764065 us-gaap:RestrictedStockMember 2017-01-01 2017-12-31 0000764065 us-gaap:PerformanceSharesMember 2019-12-31 0000764065 us-gaap:RestrictedStockMember 2016-12-31 0000764065 us-gaap:EmployeeStockOptionMember 2017-01-01 2017-12-31 0000764065 clf:DirectorsPlanMember 2019-12-31 0000764065 clf:EmployeePlansMember 2019-12-31 0000764065 us-gaap:PerformanceSharesMember 2018-02-21 2018-02-21 0000764065 us-gaap:PerformanceSharesMember 2019-02-19 2019-02-19 0000764065 clf:DirectorsPlanMember 2018-01-01 2018-12-31 0000764065 clf:DirectorsPlanMember 2017-01-01 2017-12-31 0000764065 srt:MinimumMember 2019-01-01 2019-12-31 0000764065 country:LU clf:TaxLawChangeMember 2017-01-01 2017-12-31 0000764065 clf:RepealofAMTMember 2017-01-01 2017-12-31 0000764065 us-gaap:StateAndLocalJurisdictionMember 2018-12-31 0000764065 country:US clf:TaxLawChangeMember 2017-01-01 2017-12-31 0000764065 us-gaap:StateAndLocalJurisdictionMember 2019-12-31 0000764065 clf:ValuationallowancereversalMember 2018-01-01 2018-12-31 0000764065 us-gaap:OtherLiabilitiesMember 2019-12-31 0000764065 country:LU 2019-12-31 0000764065 us-gaap:OtherLiabilitiesMember 2018-12-31 0000764065 clf:ForeigntaxcreditcarryforwardMember 2019-12-31 0000764065 srt:MaximumMember country:LU 2018-01-01 2018-12-31 0000764065 country:LU clf:DissolutionofentitiesMember 2018-01-01 2018-12-31 0000764065 srt:MaximumMember 2019-01-01 2019-12-31 0000764065 clf:DissolutionofentitiesMember 2018-01-01 2018-12-31 0000764065 country:LU clf:DissolutionofentitiesMember 2019-01-01 2019-12-31 0000764065 clf:IntercompanynotesMember country:LU 2019-01-01 2019-12-31 0000764065 clf:DissolutionofentitiesMember 2019-01-01 2019-12-31 0000764065 country:LU clf:TaxLawChangeMember 2018-01-01 2018-12-31 0000764065 srt:MaximumMember country:LU 2017-01-01 2017-12-31 0000764065 clf:CurrentyearactivityMember 2017-01-01 2017-12-31 0000764065 clf:RepealofAMTMember 2019-01-01 2019-12-31 0000764065 clf:ValuationallowancereversalMember 2017-01-01 2017-12-31 0000764065 clf:RepealofAMTMember 2018-01-01 2018-12-31 0000764065 clf:ValuationallowancereversalMember 2019-01-01 2019-12-31 0000764065 clf:TaxLawChangeMember 2019-01-01 2019-12-31 0000764065 clf:CurrentyearactivityMember 2018-01-01 2018-12-31 0000764065 clf:CurrentyearactivityMember 2019-01-01 2019-12-31 0000764065 clf:DissolutionofentitiesMember 2017-01-01 2017-12-31 0000764065 clf:TaxLawChangeMember 2018-01-01 2018-12-31 0000764065 clf:TaxLawChangeMember 2017-01-01 2017-12-31 0000764065 clf:ChangeindeferredassetsinothercomprehensiveincomeMember 2018-01-01 2018-12-31 0000764065 clf:ChangeindeferredassetsinothercomprehensiveincomeMember 2017-01-01 2017-12-31 0000764065 clf:AcquisitionofnoncontrollinginterestMember 2017-01-01 2017-12-31 0000764065 clf:ChangeindeferredassetsinothercomprehensiveincomeMember 2019-01-01 2019-12-31 0000764065 clf:AcquisitionofnoncontrollinginterestMember 2018-01-01 2018-12-31 0000764065 clf:IncludedinincometaxexpensebenefitMember 2018-01-01 2018-12-31 0000764065 clf:IncludedinincometaxexpensebenefitMember 2019-01-01 2019-12-31 0000764065 clf:AcquisitionofnoncontrollinginterestMember 2019-01-01 2019-12-31 0000764065 clf:IncludedinincometaxexpensebenefitMember 2017-01-01 2017-12-31 0000764065 clf:ForeigntaxcreditcarryforwardMember 2018-12-31 0000764065 us-gaap:OperatingSegmentsMember clf:MiningandPelletizingMember 2018-12-31 0000764065 us-gaap:OperatingSegmentsMember clf:MiningandPelletizingMember 2019-12-31 0000764065 us-gaap:EnergyRelatedDerivativeMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-12-31 0000764065 us-gaap:EnergyRelatedDerivativeMember us-gaap:DesignatedAsHedgingInstrumentMember 2018-12-31 0000764065 srt:NaturalGasReservesMember us-gaap:DesignatedAsHedgingInstrumentMember 2018-12-31 0000764065 srt:NaturalGasReservesMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-12-31 0000764065 clf:CustomerSupplyAgreementMember us-gaap:SalesMember 2017-01-01 2017-12-31 0000764065 clf:CustomerSupplyAgreementMember us-gaap:SalesMember 2019-01-01 2019-12-31 0000764065 clf:ProvisionalPricingArrangementsMember us-gaap:SalesMember 2018-01-01 2018-12-31 0000764065 us-gaap:CommodityContractMember us-gaap:CostOfSalesMember 2017-01-01 2017-12-31 0000764065 clf:CustomerSupplyAgreementMember us-gaap:SalesMember 2018-01-01 2018-12-31 0000764065 clf:ProvisionalPricingArrangementsMember us-gaap:SalesMember 2019-01-01 2019-12-31 0000764065 us-gaap:CommodityContractMember us-gaap:CostOfSalesMember 2019-01-01 2019-12-31 0000764065 clf:ProvisionalPricingArrangementsMember us-gaap:SalesMember 2017-01-01 2017-12-31 0000764065 us-gaap:CommodityContractMember us-gaap:CostOfSalesMember 2018-01-01 2018-12-31 0000764065 clf:DerivativeAssetMember us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel2Member us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:MarketApproachValuationTechniqueMember 2018-12-31 0000764065 us-gaap:OtherCurrentLiabilitiesMember clf:ProvisionalPricingArrangementsMember us-gaap:FairValueInputsLevel3Member us-gaap:NondesignatedMember us-gaap:MarketApproachValuationTechniqueMember 2018-12-31 0000764065 us-gaap:NondesignatedMember 2018-12-31 0000764065 us-gaap:NondesignatedMember 2019-12-31 0000764065 clf:DerivativeAssetMember us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel2Member us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:MarketApproachValuationTechniqueMember 2019-12-31 0000764065 us-gaap:OtherCurrentLiabilitiesMember us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel2Member us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:MarketApproachValuationTechniqueMember 2019-12-31 0000764065 us-gaap:OtherCurrentLiabilitiesMember us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel2Member us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:MarketApproachValuationTechniqueMember 2018-12-31 0000764065 clf:AsiaPacificIronOreMember 2017-01-01 2017-12-31 0000764065 clf:AsiaPacificIronOreMember 2018-01-01 2018-12-31 0000764065 clf:OtherMember 2019-01-01 2019-12-31 0000764065 clf:OtherMember 2018-01-01 2018-12-31 0000764065 clf:CanadianEntitiesMember 2019-01-01 2019-12-31 0000764065 clf:OtherMember 2017-01-01 2017-12-31 0000764065 clf:CanadianEntitiesMember 2018-01-01 2018-12-31 0000764065 clf:CanadianEntitiesMember 2017-01-01 2017-12-31 0000764065 clf:WabushScullyMineSaleMember 2017-01-01 2017-12-31 0000764065 clf:CanadianEntitiesMember 2018-12-31 0000764065 us-gaap:SegmentDiscontinuedOperationsMember clf:AsiaPacificIronOreMember 2017-01-01 2017-12-31 0000764065 us-gaap:SegmentDiscontinuedOperationsMember 2019-01-01 2019-12-31 0000764065 us-gaap:SegmentDiscontinuedOperationsMember clf:CanadianEntitiesMember 2017-01-01 2017-12-31 0000764065 us-gaap:SegmentDiscontinuedOperationsMember clf:OtherMember 2017-01-01 2017-12-31 0000764065 us-gaap:SegmentDiscontinuedOperationsMember clf:AsiaPacificIronOreMember 2019-01-01 2019-12-31 0000764065 us-gaap:SegmentDiscontinuedOperationsMember 2018-01-01 2018-12-31 0000764065 us-gaap:SegmentDiscontinuedOperationsMember 2017-01-01 2017-12-31 0000764065 us-gaap:SegmentDiscontinuedOperationsMember clf:AsiaPacificIronOreMember 2018-01-01 2018-12-31 0000764065 us-gaap:SegmentDiscontinuedOperationsMember clf:CanadianEntitiesMember 2019-01-01 2019-12-31 0000764065 us-gaap:SegmentDiscontinuedOperationsMember clf:OtherMember 2018-01-01 2018-12-31 0000764065 us-gaap:SegmentDiscontinuedOperationsMember clf:CanadianEntitiesMember 2018-01-01 2018-12-31 0000764065 us-gaap:SegmentDiscontinuedOperationsMember clf:OtherMember 2019-01-01 2019-12-31 0000764065 us-gaap:PreferredClassBMember 2019-12-31 0000764065 2018-11-26 0000764065 2019-04-24 0000764065 us-gaap:PreferredClassAMember 2019-12-31 0000764065 2019-04-01 2019-06-30 0000764065 2019-01-01 2019-03-31 0000764065 2019-07-01 2019-09-30 0000764065 clf:SpecialDividendMember 2019-10-01 2019-12-31 0000764065 us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember 2019-12-31 0000764065 us-gaap:AccumulatedTranslationAdjustmentMember 2017-12-31 0000764065 us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember 2018-12-31 0000764065 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember 2018-12-31 0000764065 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember 2017-12-31 0000764065 us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember 2017-12-31 0000764065 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember 2019-12-31 0000764065 us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember 2017-01-01 2017-12-31 0000764065 us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember 2019-01-01 2019-12-31 0000764065 us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember 2018-01-01 2018-12-31 0000764065 us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember 2019-01-01 2019-12-31 0000764065 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember 2017-01-01 2017-12-31 0000764065 us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember 2017-01-01 2017-12-31 0000764065 us-gaap:AccumulatedTranslationAdjustmentMember 2017-01-01 2017-12-31 0000764065 us-gaap:AccumulatedTranslationAdjustmentMember 2018-01-01 2018-12-31 0000764065 us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember 2018-01-01 2018-12-31 0000764065 us-gaap:AccumulatedTranslationAdjustmentMember 2019-01-01 2019-12-31 0000764065 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember 2018-01-01 2018-12-31 0000764065 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember 2019-01-01 2019-12-31 0000764065 clf:DerivativeAssetMember 2019-12-31 0000764065 us-gaap:TradeAccountsReceivableMember 2018-12-31 0000764065 us-gaap:TradeAccountsReceivableMember 2019-12-31 0000764065 clf:DerivativeAssetMember 2018-12-31 0000764065 clf:HibbingMember clf:USSteelCanadaMember 2019-12-31 0000764065 clf:HibbingMember clf:ArcelorMittalMember 2019-12-31 0000764065 clf:EmpireMember 2019-01-01 2019-12-31 0000764065 us-gaap:CapitalAdditionsMember 2019-12-31 0000764065 us-gaap:SubsequentEventMember 2020-02-18 2020-02-18 0000764065 2018-04-01 2018-06-30 0000764065 2018-10-01 2018-12-31 0000764065 2018-07-01 2018-09-30 0000764065 2018-01-01 2018-03-31 0000764065 us-gaap:ConvertibleDebtSecuritiesMember 2019-01-01 2019-03-31 0000764065 us-gaap:StockCompensationPlanMember 2019-01-01 2019-03-31 0000764065 us-gaap:StockCompensationPlanMember 2018-01-01 2018-03-31 0000764065 srt:ConsolidationEliminationsMember 2019-01-01 2019-12-31 0000764065 us-gaap:ParentMember srt:ReportableLegalEntitiesMember 2019-01-01 2019-12-31 0000764065 srt:GuarantorSubsidiariesMember srt:ReportableLegalEntitiesMember 2019-01-01 2019-12-31 0000764065 srt:ConsolidationEliminationsMember 2019-12-31 0000764065 srt:GuarantorSubsidiariesMember srt:ReportableLegalEntitiesMember 2019-12-31 0000764065 srt:NonGuarantorSubsidiariesMember srt:ReportableLegalEntitiesMember 2019-01-01 2019-12-31 0000764065 srt:ConsolidationEliminationsMember 2018-12-31 0000764065 srt:NonGuarantorSubsidiariesMember srt:ReportableLegalEntitiesMember 2018-12-31 0000764065 us-gaap:ParentMember srt:ReportableLegalEntitiesMember 2018-12-31 0000764065 us-gaap:ParentMember srt:ReportableLegalEntitiesMember 2019-12-31 0000764065 srt:GuarantorSubsidiariesMember srt:ReportableLegalEntitiesMember 2018-12-31 0000764065 srt:NonGuarantorSubsidiariesMember srt:ReportableLegalEntitiesMember 2019-12-31 0000764065 srt:ConsolidationEliminationsMember 2017-01-01 2017-12-31 0000764065 srt:NonGuarantorSubsidiariesMember srt:ReportableLegalEntitiesMember 2017-01-01 2017-12-31 0000764065 us-gaap:ParentMember srt:ReportableLegalEntitiesMember 2017-01-01 2017-12-31 0000764065 srt:GuarantorSubsidiariesMember srt:ReportableLegalEntitiesMember 2017-01-01 2017-12-31 0000764065 srt:GuarantorSubsidiariesMember srt:ReportableLegalEntitiesMember 2017-12-31 0000764065 us-gaap:ParentMember srt:ReportableLegalEntitiesMember 2016-12-31 0000764065 srt:GuarantorSubsidiariesMember srt:ReportableLegalEntitiesMember 2016-12-31 0000764065 us-gaap:ParentMember srt:ReportableLegalEntitiesMember 2017-12-31 0000764065 srt:ConsolidationEliminationsMember 2016-12-31 0000764065 srt:NonGuarantorSubsidiariesMember srt:ReportableLegalEntitiesMember 2017-12-31 0000764065 srt:NonGuarantorSubsidiariesMember srt:ReportableLegalEntitiesMember 2016-12-31 0000764065 srt:ConsolidationEliminationsMember 2017-12-31 0000764065 srt:GuarantorSubsidiariesMember srt:ReportableLegalEntitiesMember 2018-01-01 2018-12-31 0000764065 srt:ConsolidationEliminationsMember 2018-01-01 2018-12-31 0000764065 us-gaap:ParentMember srt:ReportableLegalEntitiesMember 2018-01-01 2018-12-31 0000764065 srt:NonGuarantorSubsidiariesMember srt:ReportableLegalEntitiesMember 2018-01-01 2018-12-31 clf:unit iso4217:USD clf:customer xbrli:pure utreg:T xbrli:shares iso4217:USD xbrli:shares utreg:gal clf:MMBtu iso4217:CAD clf:installment
Table of Contents

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 10-K
 
ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
 
For the fiscal year ended December 31, 2019
OR
 
TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
 
For the transition period from              to             
Commission File Number: 1-8944
clf2019def14aprimarylogoa01.jpg
CLEVELAND-CLIFFS INC.
(Exact name of registrant as specified in its charter)
 
Ohio
 
34-1464672
 
 
(State or Other Jurisdiction of
Incorporation or Organization)
 
(I.R.S. Employer
Identification No.)
 
 
 
 
 
 
 
 
 
200 Public Square,
Cleveland,
Ohio
 
44114-2315
 
 
(Address of Principal Executive Offices)
 
(Zip Code)
 
Registrant’s telephone number, including area code: (216) 694-5700
Securities registered pursuant to Section 12(b) of the Act:
Title of each class
 
Trading Symbol(s)
 
Name of each exchange on which registered
Common Shares, par value $0.125 per share
 
CLF
 
New York Stock Exchange
Securities registered pursuant to section 12(g) of the Act: NONE
Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.       Yes             NO  
Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.      Yes              No  
Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.      Yes              No  
Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).      Yes              No  
Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and "emerging growth company" in Rule 12b-2 of the Exchange Act.
Large accelerated filer
Accelerated filer
Non-accelerated filer
Smaller reporting company
 
 
Emerging growth company
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.
Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).      Yes             No  
As of June 28, 2019, the aggregate market value of the voting and non-voting common shares held by non-affiliates of the registrant, based on the closing price of $10.67 per share as reported on the New York Stock Exchange — Composite Index, was $2,839,987,963 (excluded from this figure are the voting shares beneficially owned by the registrant’s officers and directors).
The number of shares outstanding of the registrant’s common shares, par value $0.125 per share, was 271,441,006 as of February 18, 2020.
DOCUMENTS INCORPORATED BY REFERENCE
Portions of the registrant’s proxy statement for its 2020 annual meeting of shareholders are incorporated by reference into Part III.



Table of Contents

TABLE OF CONTENTS
 
 
 
 
 
 
 
 
 
Page Number
 
 
 
 
 
 
DEFINITIONS
 
 
 
 
 
 
PART I
 
 
 
 
Item 1.
Business
 
 
 
 
Information About Our Executive Officers
 
 
 
Item 1A.
Risk Factors
 
 
 
Item 1B.
Unresolved Staff Comments
 
 
 
Item 2.
Properties
 
 
 
Item 3.
Legal Proceedings
 
 
 
Item 4.
Mine Safety Disclosures
 
 
 
 
 
 
 
 
PART II
 
 
 
 
Item 5.
Market for Registrant's Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities
 
 
 
Item 6.
Selected Financial Data
 
 
 
Item 7.
Management's Discussion and Analysis of Financial Condition and Results of Operations
 
 
 
Item 7A.
Quantitative and Qualitative Disclosures About Market Risk
 
 
 
Item 8.
Financial Statements and Supplementary Data
 
 
 
Item 9.
Changes in and Disagreements With Accountants on Accounting and Financial Disclosure
 
 
 
Item 9A.
Controls and Procedures
 
 
 
Item 9B.
Other Information
 
 
 
 
 
 
PART III
 
 
 
 
Item 10.
Directors, Executive Officers and Corporate Governance
 
 
 
Item 11.
Executive Compensation
 
 
 
Item 12.
Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters
 
 
 
Item 13.
Certain Relationships and Related Transactions, and Director Independence
 
 
 
Item 14.
Principal Accountant Fees and Services
 
 
 
 
 
 
 
 
PART IV
 
 
 
 
Item 15.
Exhibits and Financial Statement Schedules
 
 
 
Item 16.
Form 10-K Summary
 
 
 
 
 
 
SIGNATURES
 
 


Table of Contents

DEFINITIONS
The following abbreviations or acronyms are used in the text. References in this report to the “Company,” “we,” “us,” “our” and “Cliffs” are to Cleveland-Cliffs Inc. and subsidiaries, collectively. References to “C$” refers to Canadian currency and “$” to United States currency.
Abbreviation or acronym
 
Term
A&R 2015 Equity Plan
 
Cliffs Natural Resources Inc. Amended and Restated 2015 Equity and Incentive Compensation Plan
ABL Facility
 
Amended and Restated Syndicated Facility Agreement by and among Bank of America, N.A., as Administrative Agent and Australian Security Trustee, the Lenders that are parties hereto, as the Lenders, Cleveland-Cliffs Inc., as Parent and a Borrower, and the Subsidiaries of Parent party hereto, as Borrowers dated as of March 30, 2015, and Amended and Restated as of February 28, 2018
Adjusted EBITDA
 
EBITDA excluding certain items such as extinguishment of debt, impacts of discontinued operations, foreign currency exchange remeasurement, severance, impairment of other long-lived assets, acquisition costs and intersegment corporate allocations of selling, general and administrative costs
AK Steel
 
AK Steel Holding Corporation and its consolidated subsidiaries (including AK Steel Corporation and its facilities in Ashland, Kentucky, Middletown, Ohio, and Dearborn, Michigan)
AK Steel 7.50% 2023 Notes
 
AK Steel Corporation’s existing 7.50% secured notes due 2023
AK Steel 7.625% 2021 Notes
 
AK Steel Corporation’s existing 7.625% unsecured notes due 2021
Algoma
 
Algoma Steel Inc. (previously, Essar Steel Algoma Inc.)
Amended 2015 Equity Plan
 
Cliffs Natural Resources Inc. 2015 Equity and Incentive Compensation Plan, as amended
APBO
 
Accumulated Postretirement Benefit Obligation
ArcelorMittal
 
ArcelorMittal (as the parent company of ArcelorMittal Mines Canada, ArcelorMittal USA and ArcelorMittal Dofasco GP, as well as, many other subsidiaries)
ArcelorMittal USA
 
ArcelorMittal USA LLC (including many of its United States affiliates, subsidiaries and representatives. References to ArcelorMittal USA comprise all such relationships unless a specific ArcelorMittal USA entity is referenced)
AMT
 
Alternative Minimum Tax
ASC
 
Accounting Standards Codification
ASU
 
Accounting Standards Update
Atlantic Basin pellet premium
 
Platts Atlantic Basin Blast Furnace 65% Fe pellet premium
Bloom Lake Group
 
Bloom Lake General Partner Limited and certain of its affiliates, including Cliffs Quebec Iron Mining ULC
BNSF
 
Burlington Northern Santa Fe, LLC
Canadian Entities
 
Bloom Lake Group, Wabush Group and certain other wholly-owned subsidiaries
CCAA
 
Companies' Creditors Arrangement Act (Canada)
CERCLA
 
Comprehensive Environmental Response, Compensation and Liability Act of 1980
Clean Water Act
 
Federal Water Pollution Control Act
CN
 
Canadian National Railway Company
Compensation Committee
 
Compensation and Organization Committee of the Board of Directors
Directors’ Plan
 
Cliffs Natural Resources Inc. Amended and Restated 2014 Nonemployee Directors’ Compensation Plan
Dodd-Frank Act
 
Dodd-Frank Wall Street Reform and Consumer Protection Act
DR-grade
 
Direct Reduction-grade
DRI
 
Direct Reduced Iron
EAF
 
Electric Arc Furnace
EBITDA
 
Earnings before interest, taxes, depreciation and amortization
Empire
 
Empire Iron Mining Partnership
EPA
 
U.S. Environmental Protection Agency
EPS
 
Earnings per share
ERM
 
Enterprise Risk Management
Exchange Act
 
Securities Exchange Act of 1934, as amended
FASB
 
Financial Accounting Standards Board
Fe
 
Iron
FeT
 
Total Iron
FIP
 
Federal Implementation Plan
FMSH Act
 
U.S. Federal Mine Safety and Health Act 1977, as amended
GAAP
 
Accounting principles generally accepted in the United States
GHG
 
Greenhouse gas
HBI
 
Hot Briquetted Iron
Hibbing
 
Hibbing Taconite Company, an unincorporated joint venture

1

Table of Contents

Abbreviation or acronym
 
Term
Hot-rolled coil steel price
 
Average annual daily market price for hot-rolled coil steel
IRC
 
Internal Revenue Code
LIBOR
 
London Interbank Offered Rate
LIFO
 
Last-in, first-out
Long ton
 
2,240 pounds
LS&I
 
Lake Superior & Ishpeming Railroad Company
Merger
 
The merger of Merger Sub with and into AK Steel, with AK Steel surviving the merger as a wholly owned subsidiary of Cliffs, subject to the conditions set forth in the Merger Agreement
Merger Agreement
 
Agreement and Plan of Merger, dated as of December 2, 2019, among Cliffs, AK Steel and Merger Sub
Merger Sub
 
Pepper Merger Sub Inc., a direct, wholly owned subsidiary of Cliffs
Metric ton
 
2,205 pounds
MMBtu
 
Million British Thermal Units
MPCA
 
Minnesota Pollution Control Agency
MSHA
 
U.S. Mine Safety and Health Administration
Monitor
 
FTI Consulting Canada Inc.
NAAQS
 
National Ambient Air Quality Standards
Net ton
 
2,000 pounds
New ABL Facility
 
New asset-based revolving credit facility expected to be entered into in connection with the Merger to replace the ABL Facility
New Cliffs Secured/Unsecured Notes
 
New series of secured notes and a new series of unsecured notes expected to be entered into in connection with the Merger to repurchase or redeem the AK Steel 7.50% 2023 Notes and, depending on market and other conditions, the AK Steel 7.625% 2021 Notes
NO2
 
Nitrogen dioxide
NOx
 
Nitrogen oxide
Northshore
 
Northshore Mining Company
NYSE
 
New York Stock Exchange
OPEB
 
Other postretirement benefits
OPEB cap
 
Medical premium maximums
OSHA
 
Occupational Safety and Health Administration
PBO
 
Projected benefit obligation
Platts 62% price
 
Platts IODEX 62% Fe Fines cost and freight North China
PPI
 
Producer Price Indices
S&P
 
Standard & Poor's Rating Services, a division of Standard & Poor's Financial Services LLC, a subsidiary of The McGraw-Hill Companies, Inc., and its successors
SEC
 
U.S. Securities and Exchange Commission
Securities Act
 
Securities Act of 1933, as amended
Silver Bay Power
 
Silver Bay Power Company
SIP
 
State Implementation Plan
SO2
 
Sulfur dioxide
STRIPS
 
Separate Trading of Registered Interest and Principal of Securities
Tilden
 
Tilden Mining Company L.C.
TMDL
 
Total Maximum Daily Load
Topic 606
 
ASC Topic 606, Revenue from Contracts with Customers
Topic 815
 
ASC Topic 815, Derivatives and Hedging
TRIR
 
Total Recordable Incident Rate
TSR
 
Total Shareholder Return
United Taconite
 
United Taconite LLC
U.S.
 
United States of America
U.S. Steel
 
U.S. Steel Corporation and all subsidiaries
USW
 
United Steelworkers
VEBA
 
Voluntary Employee Benefit Association trusts
Wabush Group
 
Wabush Iron Co. Limited and Wabush Resources Inc., and certain of their affiliates, including Wabush Mines (an unincorporated joint venture of Wabush Iron Co. Limited and Wabush Resources Inc.), Arnaud Railway Company and Wabush Lake Railway Company
WEPC
 
Wisconsin Electric Power Company

2

Table of Contents

PART I
Item 1.
Business
Introduction
Founded in 1847, Cleveland-Cliffs Inc. is the largest and oldest independent iron ore mining company in the United States. We are a major supplier of iron ore pellets to the North American steel industry from our mines and pellet plants located in Michigan and Minnesota. In 2020, we expect to be the sole producer of HBI in the Great Lakes region with the startup of our first production plant in Toledo, Ohio. Driven by the core values of safety, social, environmental and capital stewardship, our employees endeavor to provide all stakeholders with operating and financial transparency.
We are organized according to our differentiated products and have two reportable segments – the Mining and Pelletizing segment and the Metallics segment.
In our Mining and Pelletizing segment, we currently own or co-own four operational iron ore mines plus one indefinitely idled mine. We are currently operating one iron ore mine in Michigan and two iron ore mines in Minnesota. Additionally, we have a 23% ownership stake in a third iron ore mine in Minnesota. All four mines are currently operating at or near their respective current annual capacity. In our Metallics segment, we expect to complete construction of our HBI production plant in Toledo, Ohio and begin operations during the first half of 2020.
On December 2, 2019, we entered into the Merger Agreement, pursuant to which we have agreed to acquire AK Steel, a leading North American producer of flat-rolled carbon, stainless and electrical steel products, primarily for the automotive, infrastructure and manufacturing markets. We expect to complete the Merger in the first quarter of 2020. We believe the transaction will transform us into a best-in-class iron ore and steel producer with industry leading margins and a self-sufficiency in iron ore, along with the synergy value created from the combination of two public companies. Unless otherwise noted, discussion of our business and results of operations in this Annual Report on Form 10-K refers to our continuing operations on a stand-alone basis without giving effect to the Merger.
Protecting our Mining and Pelletizing Business
We are the market-leading iron ore producer in the U.S., supplying differentiated iron ore pellets under long-term contracts to major North American blast furnace steel producers. We have the unique advantage of being a low-cost, high-quality, iron ore pellet producer with significant transportation and logistics advantages to serve the Great Lakes steel market. The pricing structure and long-term nature of our existing contracts, along with our low-cost operating profile, position our Mining and Pelletizing segment as a strong cash flow generator in most commodity pricing environments. Since instituting our strategy in 2014 of focusing on this business, we have achieved significant accomplishments, including maximizing commercial leverage in pricing and securing sales volume certainty with steelmakers throughout the Great Lakes region, improving operating reliability by making operational improvements, realizing more predictability in cash flows, developing new demand avenues in the metallics industry, embracing the global push toward environmental stewardship and developing new pellet products to meet ever-evolving market demands.
We recognize the importance of our current strong position in the North American blast furnace steel industry, and one of our top priorities is to protect and enhance the market position of our Mining and Pelletizing business. This involves continuing to deliver high-quality, custom-made pellets that allow our customers to remain competitive in the quality, production efficiency, and environmental friendliness of their steel products. Protecting this business also involves continually evaluating opportunities to preserve our customer base, expand our production capacity and increase ore reserve life. In 2017, we achieved key accomplishments toward these goals by acquiring the remaining minority stake in our Tilden and Empire mines as well as additional real estate interests in Minnesota. In 2018, we began supplying pellets under two new customer supply agreements in the Great Lakes region. In addition, we executed the efficient exit of our Asia Pacific Iron Ore business, officially completing the divestiture of the Company's non-core iron ore assets. In 2019, we completed the upgrades at our Northshore mine to begin commercially producing DR-grade pellets.
The acquisition of AK Steel, when complete, is expected to ensure pellet volume commitments for approximately 6 million long tons of pellets, to complement our existing long-term minimum volume pellet offtake agreements with other key integrated steel producers and pellets to be consumed at our Toledo HBI production plant.

3

Table of Contents

Expanding our Customer Base and Product Offering
The acquisition of AK Steel, when complete, is expected to allow us to benefit from a larger and more diverse base of customers, with less overall emphasis on commodity-linked contracts. The expansion of our customer base into the automotive industry, as well as other steel consuming manufacturers, through the acquisition of AK Steel is expected to generate more predictable earnings and cash flows due to the focus on value-added and non-commoditized products, and less exposure to volatile commodity indices. AK Steel is one of the few steel producers capable of producing the carbon and stainless steel grades critical to automotive lightweighting trends. AK Steel generally supplies more advanced steel products than EAF steelmakers, who have gained market share from other blast furnaces on less advanced commodity-grade steels. As currently configured, EAFs are largely unable to supply the highly-specified products that AK Steel primarily sells.
Although AK Steel has a different customer base compared to other blast furnace steelmakers, we cannot ignore the ongoing shift of steelmaking share in the U.S. away from our other blast furnace customers to the EAF steelmakers. Over the past 25 years, the market share of EAFs has nearly doubled. However, as EAFs have moved to higher-value steel products, they require more high-quality iron ore-based metallics instead of lower-grade scrap as raw material feedstock. As a result of this trend, one of our top strategic priorities will be to become a critical supplier of the EAF market by providing these specialized metallics.
In June 2017, we announced the planned construction of an HBI production plant in Toledo, Ohio. Over the past 32 months, we have made significant progress on the construction of this plant. During 2018, we increased the expected productive capacity of the Toledo HBI production plant from 1.6 million to 1.9 million metric tons per year based on market analysis, greater-than-expected customer demand and expansion opportunities identified during the construction process. We estimate the construction cost to be approximately $830 million plus a contingency of up to 20%, excluding capitalized interest, of which approximately $700 million was paid as of December 31, 2019. We expect that the HBI production plant, once operational, will consume approximately 2.8 million long tons of our DR-grade pellets per year. During 2019, we announced that we expect to reach commercial production ahead of schedule, in the first half of 2020.
We expect our HBI partially to replace the over 3 million metric tons of ore-based metallics that are imported into the Great Lakes region every year from Russia, Ukraine, Brazil and Venezuela, as well as the nearly 20 million metric tons of scrap used in the Great Lakes area every year. The Toledo site is in close proximity to over 20 EAFs, giving us a natural competitive freight advantage over import competitors. Not only does this production plant create another outlet for our high-margin pellets, but it also presents an attractive economic opportunity for us. As the only producer of DR-grade pellets in the Great Lakes region and with access to abundant, low-cost natural gas, we will be in a unique position to serve clients in the area and grow our customer base.
The acquisition of AK Steel, when complete, provides another potential outlet for HBI as it can also be used in integrated steel operations to increase productivity and reduce carbon footprint, allowing for more environmentally friendly steelmaking. AK Steel has used imported HBI in the past for these purposes.
Segments
Operating segments are defined as components of an enterprise for which separate financial information is available that is evaluated regularly by the chief operating decision maker, or decision-making group, to decide how to allocate resources and to assess performance. Our Company’s continuing operations are organized and managed in two business units according to our differentiated products: Mining and Pelletizing and Metallics. Until operational, expenses incurred in the Metallics segment will be recorded to Miscellaneous - net. Each of our business units qualifies as an operating segment with its results regularly reviewed by our chief operating decision maker. Our chief operating decision maker is our Chief Executive Officer. As of December 31, 2019, the Mining and Pelletizing segment and the Metallics segment are both reportable segments in accordance with ASC Topic 280, Segment Reporting.

4

Table of Contents

Mining and Pelletizing Segment
We are a major producer of iron ore pellets, primarily selling production from our Mining and Pelletizing segment to integrated steel companies in the U.S. and Canada. We operate three iron ore mines: the Tilden mine in Michigan and the Northshore and United Taconite mines in Minnesota. Additionally, we have a 23% ownership stake in the Hibbing mine in Minnesota. These mines currently have an annual rated capacity of 27.4 million long tons of iron ore pellet production, representing 55% of total U.S. pellet production capacity. Based on our equity ownership in these mines, our share of the annual rated production capacity is currently 21.2 million long tons, representing 42% of total U.S. annual pellet capacity. The Empire mine located in Michigan, which historically had annual rated capacity of 5.5 million long tons, was indefinitely idled beginning in August 2016. During 2017, we acquired the remaining noncontrolling interest of the Empire and Tilden mines from ArcelorMittal USA and U.S. Steel, respectively. On August 12, 2019, our subsidiary, Cliffs Mining Company, ceased performing manager duties for the Hibbing mine and transitioned those duties to ArcelorMittal USA. Prior to this transition, we managed the Hibbing mine and our joint venture partners made required capital contributions and paid for their share of the iron ore pellets that we produced.
The following chart summarizes the estimated annual pellet production capacity and percentage of total U.S. pellet production capacity for each of the respective iron ore producers as of December 31, 2019:
U.S. Pellet
Annual Rated Capacity Tonnage
 
 
Current Estimated Capacity
(Long Tons in Millions)1
 
Percent of Total U.S. Capacity
All Cliffs’ owned and co-owned mines
 
27.4

 
54.8
%
Other U.S. mines
 
 
 
 
U.S. Steel’s Minnesota ore operations
 
 
 
 
Minnesota Taconite
 
14.3

 
28.6

Keewatin Taconite
 
5.4

 
10.8

Total U.S. Steel
 
19.7

 
39.4

ArcelorMittal USA Minorca mine
 
2.9

 
5.8

Total other U.S. mines
 
22.6

 
45.2

Total U.S. mines
 
50.0

 
100.0
%
 
 
 
 
 
1 Empire mine was excluded from the estimated capacity calculation as it is indefinitely idled.
Our Mining and Pelletizing segment production generally is sold pursuant to long-term supply agreements. For the year ended December 31, 2019, our owned and co-owned mines produced a total of 25.7 million long tons of iron ore pellets. The 2019 production included 19.9 million long tons for our account and 5.8 million long tons on behalf of our steel company partners associated with the Hibbing mine. During 2018 and 2017, our owned and co-owned mines produced a total of 26.3 million and 25.5 million long tons, respectively.
We produce various grades of iron ore pellets, including standard, fluxed and DR-grade, generally for use in our customers’ operations as part of the steelmaking process. The variation in grade of iron ore pellets results from the specific chemical and metallurgical properties of the ores at each mine, the requirements of end users' steelmaking processes and whether or not fluxstone is added in the process. Although the grade or grades of pellets currently delivered to each customer are based on that customer’s preferences, which depend in part on the characteristics of the customer’s steelmaking operation, in certain cases our iron ore pellets can be used interchangeably. Standard pellets require less processing, are generally the least costly pellets to produce and are called “standard” because no ground fluxstone, such as limestone or dolomite, is added to the iron ore concentrate before turning the concentrate into pellets. In the case of fluxed pellets, fluxstone is added to the concentrate, which produces pellets that can perform at higher productivity levels in the customer’s specific blast furnace and will minimize the amount of fluxstone the customer may be required to add to the blast furnace. DR-grade pellets require additional processing to make a pellet that contains higher iron and lower silica content than a standard pellet. Unlike standard or fluxed pellets, DR-grade pellets are produced to be fed into a DRI facility, which then are converted into DRI or HBI.
Additionally, as the EAF steel market continues to grow in the U.S., there is an opportunity for our iron ore to serve this market by providing pellets to the alternative metallics market to produce DRI, HBI and/or pig iron. During 2019, we began commercially producing and selling DR-grade pellets to our Metallics business unit and third parties.

5

Table of Contents

Each of our Mining and Pelletizing segment mines is located near the Great Lakes. The majority of our iron ore pellets are transported via railroads to loading ports for shipment via vessel to blast furnace steelmakers in North America.
Our sales are influenced by seasonal factors in the first quarter of the year as shipments and sales are restricted due to closure of the Soo Locks at Sault Ste. Marie and the Welland Canal on the Great Lakes because of winter weather. During the first quarter, we continue to produce our products, but we cannot ship most of those products via lake vessel until the conditions on the Great Lakes are navigable, which causes our first and second quarter inventory levels to rise. Our limited practice of shipping product to ports on the lower Great Lakes or to customers’ facilities prior to the transfer of control has somewhat mitigated the seasonal effect on first and second quarter inventories, as shipment from this point to the customers’ operations is not limited by weather-related shipping constraints. As of December 31, 2019 and December 31, 2018, under Topic 606, we had finished goods of 1.0 million long tons and 0.8 million long tons, respectively, in transit or stored at ports and customer facilities on the lower Great Lakes to service customers, for which revenue had yet to be recognized. As of December 31, 2017, under the previous accounting standard, we had finished goods of 1.5 million long tons stored at ports and customer facilities on the lower Great Lakes to service customers for which revenue had yet to be recognized. Refer to NOTE 1 - BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES for further discussion on revenue recognition.
Mining and Pelletizing Customers
Our Mining and Pelletizing segment revenues primarily are derived from sales of iron ore pellets to the North American integrated steel industry, consisting primarily of three major customers. Generally, we have multi-year supply agreements with our customers. Sales volume under these agreements largely is dependent on customer requirements, and in certain cases, we are the sole supplier of iron ore to the customer. Most agreements contain a base price that is adjusted annually using one or more adjustment factors. Factors that could result in price adjustments under our contracts include changes in the Platts 62% price, hot-rolled coil steel price, the Atlantic Basin pellet premium, published Platts international indexed freight rates and changes in specified PPI, including those for industrial commodities, fuel and steel.
During 2019, 2018 and 2017, we sold 18.6 million, 20.6 million and 18.7 million long tons of iron ore product, respectively, to third parties from our share of production from our Mining and Pelletizing segment mines. Additionally, during 2019, we had intersegment sales of 0.8 million long tons of iron ore product. Refer to Concentration of Customers below for additional information regarding our major customers.
Metallics Segment
In June 2017, we announced the construction of an HBI production plant in Toledo, Ohio and in April 2018, we celebrated the ground breaking for the start of construction. Over the past 32 months, we have made significant progress on the construction of this plant. HBI is a specialized high-quality iron alternative to scrap that, when used as a feedstock, allows an EAF to produce more valuable grades of steel. We expect our HBI partially to replace the over 3 million metric tons of ore-based metallics that are imported into the Great Lakes region every year from Russia, Ukraine, Brazil and Venezuela, as well as approximately 20 million metric tons of scrap used in the Great Lakes area every year.
During 2018, we increased the expected productive capacity of the Toledo HBI production plant from 1.6 million to 1.9 million metric tons per year based on market analysis, greater-than-expected customer demand and expansion opportunities identified during the construction process. We expect that the HBI production plant, once operational, will consume approximately 2.8 million long tons of DR-grade pellets per year from our Mining and Pelletizing segment. We expect to reach commercial production in the first half of 2020.
Discontinued Operations
Unless otherwise noted, discussion of our business and results of operations in this Annual Report on Form 10-K refers to our continuing operations.
Asia Pacific Iron Ore Operations
During 2018, we committed to a course of action leading to the permanent closure of the Asia Pacific Iron Ore mining operations and sold all of the assets of our Asia Pacific Iron Ore business through a series of sales to third parties. As a result of our exit, management determined that our Asia Pacific Iron Ore operating segment met the criteria to be classified as held for sale and a discontinued operation under ASC Topic 205, Presentation of Financial Statements.

6

Table of Contents

As such, all current and historical Asia Pacific Iron Ore operating segment results are classified within discontinued operations.
Historically, the Asia Pacific Iron Ore operations served the Asian iron ore markets with direct-shipped fines and lump ore. During 2018 and 2017, we produced 2.7 million and 10.1 million metric tons, respectively, from our Asia Pacific Iron Ore operation. During 2018 and 2017, we sold 3.9 million and 9.8 million metric tons of iron ore, respectively, from our Asia Pacific Iron Ore operation.
Refer to NOTE 13 - DISCONTINUED OPERATIONS for further discussion of the Asia Pacific Iron Ore segment.
Canadian Operations
During 2015, we announced that the Bloom Lake Group and the Wabush Group commenced restructuring proceedings in Montreal, Quebec under the CCAA to address the immediate liquidity issues and to preserve and protect their assets for the benefit of all stakeholders while restructuring and/or sale options were explored.
The Bloom Lake Group and the Wabush Group filed a joint plan of compromise and arrangement that was approved by the required majorities of each unsecured creditor class and was sanctioned by the Court in June 2018. During July 2018, amendments were made to the plan to address the manner in which certain distributions under the plan would be effected and the plan was implemented. Under the terms of the amended plan, all employee claims, all claims by the Bloom Lake Group, the Wabush Group and their respective creditors against us as well as all of our claims against the Bloom Lake Group and the Wabush Group were resolved.
Expenses directly associated with the Canadian Entities are classified within discontinued operations. Refer to NOTE 13 - DISCONTINUED OPERATIONS for further discussion of the Canadian operations.
Applied Technology, Research and Development
We have been a leader in iron ore mining and processing technology since inception and have been in operation for over 170 years. We operated some of the first mines on Michigan’s Marquette Iron Range and pioneered early open-pit and underground mining methods. From the first application of electrical power in Michigan’s underground mines to the use of today’s sophisticated computers and global positioning satellite systems, we have been a leader in the application of new technology to the centuries-old business of mineral extraction.
We are also a pioneer in iron ore pelletizing with over 60 years of experience. We are able to produce customized, environmentally friendly pellets to meet each customer’s blast furnace specifications and produce both standard and fluxed pellets. Today, our engineering and technical staffs are engaged in full-time technical support of our operations, improvement of existing products and development of new products. Using our technical expertise and strong market position in the U.S. to increase our product offering, we have started producing DR-grade pellets. In recent years, we shipped DR-grade pellets, which were successfully processed in multiple DRI reactors to produce a high-quality DRI product.
With our experienced technical professionals and unsurpassed reputation for our pelletizing technology, we continue to deliver a world-class quality product to our customers. We are a pioneer in the development of emerging reduction technologies, a leader in the extraction of value from challenging resources and a front-runner in the implementation of safe and sustainable technology. Our technical experts are dedicated to excellence and deliver superior technical solutions tailored to our customer base. We are also devoted to promoting environmental sustainability in our industry, primarily evidenced with the development of our HBI facility in Toledo, Ohio. Similar to the market shift to pellets over 60 years ago, we recognize the need to serve the growing EAF market. We expect our introduction of HBI to the Great Lakes EAF market will be notable in the evolution of the steel industry.

7

Table of Contents

Concentration of Customers
In 2019, 2018 and 2017, three customers individually accounted for more than 10% of our consolidated product revenue. Product revenue from those customers totaled $1.8 billion, $2.1 billion and $1.5 billion of our total consolidated product revenue in 2019, 2018 and 2017, respectively. The following represents sales revenue attributable to each of these customers as a percentage of total product sales for those years:
 
 
Percentage
Product Revenue
Customer1
 
2019
 
2018
 
2017
ArcelorMittal
 
50%
 
57%
 
48%
AK Steel
 
29%
 
25%
 
29%
Algoma
 
18%
 
13%
 
11%
 
1 Includes subsidiaries.
ArcelorMittal
Our pellet supply agreements with ArcelorMittal USA are based on customer requirements, except for the Indiana Harbor East facility, which is based on customer contract obligations. Currently, the parties participate in a long-term agreement, which became effective October 31, 2016, for the sale and delivery of ArcelorMittal USA’s annual tonnage requirements that fall within a specific range of volume. This agreement expires at the end of December 2026. Additionally, in 2018 we entered into a multi-year agreement with ArcelorMittal Dofasco to sell and deliver a portion of its annual pellet consumption requirements.
ArcelorMittal USA is a 62.3% equity participant in Hibbing. During 2017, we acquired the 21% ownership interest of ArcelorMittal USA in Empire as part of an agreement to distribute the noncontrolling interest net assets of the mine.
In 2019, 2018 and 2017, our Mining and Pelletizing segment pellet sales to ArcelorMittal were 8.8 million, 10.1 million and 8.4 million long tons, respectively.
AK Steel
In August 2013, we entered into an agreement with AK Steel to provide iron ore pellets for use in its Middletown, Ohio and Ashland, Kentucky blast furnace facilities, the latter of which is currently idled. This contract includes minimum and maximum tonnage requirements for each year between 2014 and 2023. In 2019 and 2018, through contract amendments, we added tonnage with AK Steel above the maximum tonnage requirements specific to each contract year.
In 2015, we entered into an amended and restated agreement with AK Steel after it acquired Severstal Dearborn, LLC, under which we supply all of the Dearborn, Michigan facility’s blast furnace pellet requirements through 2022, subject to specified minimum and maximum requirements in certain years.
On December 2, 2019, we entered into the Merger Agreement with AK Steel pursuant to which we will acquire all of the issued and outstanding shares of AK Steel common stock pursuant to the Merger. We expect to complete the Merger in the first quarter of 2020. Completion of the Merger is subject to various conditions, such as satisfaction or waiver of certain specified closing conditions, and it is possible that factors outside of our control could result in the Merger being completed at a later time or not at all. The Merger Agreement also contains certain termination rights that may be exercised by either us or AK Steel. We plan to complete the Merger as soon as reasonably practicable following the satisfaction of all applicable conditions.
In 2019, 2018 and 2017, our Mining and Pelletizing segment pellet sales to AK Steel were 5.5 million, 5.8 million and 5.6 million long tons, respectively.
Algoma
We have a long-term supply agreement under which we have agreed to provide a portion of the Canadian steelmaker's pellet needs through 2024. Additionally, Algoma entered into agreements with us wherein we sell additional incremental tonnage that equates to Algoma's annual iron ore pellet consumption. These agreements began in 2016 and run through December 2020.

8

Table of Contents

In 2019, 2018 and 2017, our Mining and Pelletizing segment pellet sales to Algoma were 3.4 million, 3.5 million and 2.5 million long tons, respectively.
Competition
In our Mining and Pelletizing business segment, we primarily sell our product to steel producers with operations in North America. We compete directly with steel companies that own interests in iron ore mines in the United States and/or Canada, including U.S. Steel, and with major iron ore pellet exporters from Eastern Canada and Brazil.
A number of factors beyond our control affect the markets in which we sell our iron ore. Continued demand for our iron ore and the prices obtained by us primarily depend on the consumption patterns of the steel industry in the U.S., China and elsewhere around the world, as well as the availability, location, cost of transportation and competing prices.
Environment
Our mining activities are subject to various laws and regulations governing the protection of the environment. We conduct our operations in a manner that is protective of public health and the environment and believe our operations are in compliance with applicable laws and regulations in all material respects.
Environmental issues and their management continued to be an important focus at each of our operations throughout 2019. In the construction and operation of our facilities, substantial costs have been and will continue to be incurred to comply with regulatory requirements and avoid undue effect on the environment. In 2019, 2018 and 2017, our capital expenditures relating to environmental matters totaled approximately $9 million, $10 million and $21 million, respectively. It is estimated that capital expenditures for environmental improvements will total approximately $26 million in 2020 for various water treatment, air quality, dust control, tailings management, selenium management and other miscellaneous environmental projects.
Regulatory Developments
Various governmental bodies continually promulgate new or amended laws and regulations that affect us, our customers and our suppliers in many areas, including waste discharge and disposal, the classification of materials and products, air and water discharges and other environmental, health and safety matters. Although we believe that our environmental policies and practices are sound and do not expect that the application of any current laws, regulations or permits reasonably would be expected to result in a material adverse effect on our business or financial condition, we cannot predict the collective potential adverse impact of the expanding body of laws and regulations.
Specifically, there are several notable proposed or potential rulemakings or activities that could have a material adverse impact on our facilities in the future depending on their ultimate outcome: Minnesota's potential revisions to the sulfate wild rice water quality standard; evolving water quality standards for selenium and conductivity; scope of the Clean Water Act and the definition of “Waters of the United States”; Minnesota's Mercury TMDL and associated rules governing mercury air emission reductions; Climate Change and GHG Regulation; Regional Haze FIP Rule; legacy property, NO2 and SO2 NAAQS; and increased administrative and legislative initiatives related to financial assurance obligations for CERCLA, mining and reclamation obligations.
Minnesota’s Sulfate Wild Rice Water Quality Standard
The Minnesota Governor established a Wild Rice Task Force by Executive Order in May 2018 that provided recommendations to the Governor’s Office on wild rice restoration and regulation. The existing water quality standard for wild rice has not been applied to any of our discharge permits or enforced in decades, and it may be unenforceable because of legislation and because the water bodies to which the existing standard applies have never been identified specifically in rule, nor are there criteria for identifying them. MPCA is complying with the legislation that prohibits enforcement of the water quality standard until the obsolete standard is updated based on modern science. For these reasons, the impact of the proposed wild rice water quality standard to us is not estimable at this time, but it could have an adverse material impact if we are required to significantly reduce sulfate in our discharges.
Selenium Discharge Regulation
In Michigan, Empire and Tilden have implemented compliance plans to manage selenium according to the permit conditions. Empire and Tilden submitted the first permit-required Selenium Storm Water Management Plan to the Michigan Department of Environmental, Great Lakes, and Energy ("EGLE") in December 2011 and have updated it annually as required. The Selenium Storm Water Management Plans have outlined the activities that have been

9

Table of Contents

undertaken to address selenium in storm water discharges from our Michigan operations including an assessment of potential impacts to surface and ground water. The remaining infrastructure needed for implementation of the storm water collection and conveyance system will likely be completed in 2020. A storm water treatment system for both facilities is anticipated sometime before 2028. As of December 31, 2019, included within our Empire asset retirement obligation is a discounted liability of approximately $88 million, which includes the estimated costs associated with the construction of Empire's portion of the required infrastructure and expected future operating costs of the treatment facilities. Additionally, included within our Tilden future capital plan is approximately $25 million for the construction of Tilden's portion of the required infrastructure. We are continuing to assess and develop cost effective and sustainable treatment technologies.
In July 2016, the EPA published new selenium fish tissue limits and lower lentic and lotic water column concentration criteria, which may someday increase the cost for treatment should EGLE adopt these new standards in lieu of the existing limits required by the Great Lakes Water Quality Initiative. Accordingly, we cannot reasonably estimate the timing or long-term impact of the water quality criteria to our business.
Mercury TMDL and Minnesota Taconite Mercury Reduction Strategy
Since the 1990’s the taconite industry has voluntarily reduced and removed mercury products and supported development of mercury emission reduction technology. While TMDL regulations are contained in the Clean Water Act, Minnesota developed in 2007 a Statewide Mercury TMDL that set an objective for 93% mercury air emission reductions from 1990 levels for sources within Minnesota. The State of Minnesota has acknowledged that approximately 90% of the mercury entering the state’s airshed is from other national and international sources.
In September 2014, Minnesota promulgated the Mercury Air Emissions Reporting and Reduction Rules mandating mercury air emissions reporting and reductions from certain sources, including taconite facilities. The rule is applicable to all of our Minnesota operations and required submittal of a Mercury Reduction Plan to the MPCA by the end of 2018 with plan implementation requirements becoming effective on January 1, 2025. In the Mercury Reduction Plan, facilities must evaluate if available control technologies can technically achieve a 72% mercury reduction rate. If available control technologies cannot technically achieve a 72% mercury reduction rate, the facilities must propose alternative mercury reduction measures. One of the main tenets agreed upon for evaluating potential mercury reduction technologies during TMDL implementation and 2014 rule development proceedings was that the selected technology must meet the following “Adaptive Management Criteria”: the technology must be technically feasible; must be economically feasible; must not impact pellet quality; and must not cause excessive corrosion in the indurating furnaces or air pollution control equipment.
The Mercury Reduction Plans for our Minnesota facilities were submitted to the MPCA in December 2018 and are currently being reviewed by the MPCA. There is currently no proven technology to cost effectively reduce mercury emissions from taconite furnaces to the target level of 72% while satisfying all four Adaptive Management Criteria. The Mercury Reduction Plans that were submitted to MPCA include documentation that describes the results of detailed engineering analysis and research testing on potential technologies to support this determination. The results of this analysis will guide further dialogue with the MPCA. Potential impacts to us are not estimable at this time because the submitted Mercury Reduction Plans are currently being reviewed by MPCA.
Climate Change and GHG Regulation
With the complexities and uncertainties associated with the U.S. and global navigation of the climate change issue as a whole, one of our potentially significant risks for the future is mandatory carbon pricing obligations. Policymakers are in the design process of carbon regulation at the state, regional, national and international levels. The current regulatory patchwork of carbon compliance schemes presents a challenge for multi-facility entities to identify their near-term risks. Amplifying the uncertainty, the dynamic forward outlook for carbon pricing obligations presents a challenge to large industrial companies to assess the long-term net impacts of carbon compliance costs on their operations. Our exposure on this issue includes both the direct and indirect financial risks associated with the regulation of GHG emissions, as well as potential physical risks associated with climate change adaptation. We are continuing to review the physical risks related to climate change. As an energy-intensive business, our GHG emissions inventory includes a broad range of emissions sources, such as iron ore furnaces and kilns, boilers, and diesel mining equipment, among others. As such, our most significant regulatory risks are: (1) the costs associated with on-site emissions levels (direct impacts), and (2) indirect costs passed through to us from electrical and fuel suppliers (indirect impacts).
Internationally, mechanisms to reduce emissions are being implemented in various countries, with differing designs and stringency, according to resources, economic structure and politics. The Paris Agreement to reduce global GHG emissions and limit global temperature increases to 2 degrees Celsius became effective in November 2016 with

10

Table of Contents

196 signatory countries. During the Obama Administration, the U.S. became a signatory to the Paris Agreement with a pledge to reduce its GHG emissions by 26-28% from 2005 levels by 2025. In June 2017, President Trump announced that the U.S. would cease all participation in the Paris Agreement and initiate formal withdrawal proceedings which are expected to be finalized in November 2020. Continued political attention to issues concerning climate change, the role of human activity in it and potential mitigation through regulation may have a material impact on our customer base, operations and financial results in the future.
In the U.S., future federal and/or state carbon regulation potentially presents a significantly greater impact to our operations. To date, the U.S. Congress has not legislated carbon constraints. In the absence of comprehensive federal carbon legislation, numerous state, regional, and federal regulatory initiatives are under development or are becoming effective, thereby creating a disjointed approach to GHG control and potential carbon pricing impacts.
Due to the potential patchwork of federal, state or regional carbon restriction schemes, our business and customer base could suffer negative financial impacts over time as a result of increased energy, environmental and other costs to comply with the limitations that would be imposed on GHG emissions. We believe our exposure can be reduced substantially by numerous factors, including currently contemplated regulatory flexibility mechanisms, such as allowance allocations, fixed process emissions exemptions, offsets and international provisions; emissions reduction opportunities, including energy efficiency, biofuels and fuel flexibility; and business opportunities associated with pursuing combined heat and power partnerships and new products, including DR-grade pellets, HBI, fluxed pellets and other efficiency-improving technologies.
We have worked proactively to develop a comprehensive, enterprise-wide GHG management strategy aimed at considering all significant aspects associated with GHG initiatives to plan effectively for and manage climate change issues, including risks and opportunities as they relate to the environment; stakeholders, including shareholders and the public; legislative and regulatory developments; operations; products and markets. Our direct Scope 1 and indirect Scope 2 GHG emissions, on a GHG-intensity basis for the Mining and Pelletizing segment, have been reduced by 16% compared to 2005 emissions with an objective to reduce the GHG intensity by 36% by the end of 2020 compared to 2005 emissions. By 2020 we expect to meet the U.S. 2015 Paris Agreement pledge of 26 to 28% GHG emissions reduction from 2005 baseline levels five years ahead of the 2025 target for both Scope 1 and Scope 2 emissions.  On a mass basis, we have reduced our Scope 1 and Scope 2 GHG mass emissions at our Mining and Pelletizing segment from 2005 levels by 30% through 2018 and expect to reduce these emissions from the 2005 levels by 46% through 2020.
Regional Haze FIP Rule
In June 2005, the EPA finalized amendments to its regional haze rules. The rules require states to establish goals and emission reduction strategies for improving visibility in all Class I national parks and wilderness areas to natural background levels by 2064. Among the states with Class I areas are Michigan and Minnesota, in which we currently own mining operations. The first phase of the regional haze rule required analysis and installation of Best Available Retrofit Technology ("BART") on eligible emission sources and incorporation of BART and associated emission limits into SIPs.
EPA disapproved Minnesota's and Michigan's BART SIP for taconite furnaces and instead promulgated a Taconite Regional Haze FIP in February 2013. We petitioned the Eighth Circuit Court of Appeals for a review of the FIP, and filed a joint motion for stay of the 2013 FIP, which was granted in June 2013. We reached a settlement agreement with EPA, which was subsequently published in the Federal Register to implement components of the settlement agreement in April 2016, with an effective date of May 12, 2016. We believe the 2016 Regional Haze FIP reflects progress toward a more technically and economically feasible regional haze implementation plan. In November 2016, the Eighth Circuit Court of Appeals terminated the June 2013 stay and extended the deadlines in the original 2013 FIP. Cost estimates associated with implementation of the 2013 and 2016 FIPs are reflected in our five-year capital plan.
Due to inconsistencies in language describing the procedures for calculating NOx emission limits between the settlement agreement and the 2016 FIP final rule, we jointly filed a Petition for Reconsideration and Petition for Judicial Review in June 2016. We have been working toward a settlement agreement with EPA to resolve the outstanding issue with the emission limit calculation method and anticipate resolution of the issue in 2020. The outcome of this proceeding is not expected to have a material adverse impact to the business.
The states have begun to evaluate remaining visibility impacts to Class I air sheds and progress against the Uniform Rate of Progress glide path, which culminates in achieving natural visibility conditions in 2064, as part of the second Regional Haze decadal review period (2018-2028). The second decadal review will examine if additional

11

Table of Contents

technological controls are warranted for certain sources. The states are required to submit their updated Regional Haze SIPs by July 2021. At this time, we cannot reasonably estimate the likelihood or extent of any additional emission control requirements that may arise from Minnesota or Michigan's forthcoming 2021 SIP submittal to EPA, but we will continue to monitor developments in the interim.
Former Cliffs-Dow Plant Site
We previously had a minority ownership interest in Cliffs-Dow Chemical, a joint venture that owned a charcoal production and wood chemical refining facility until the joint venture shares were sold in 1968 to a third party. The subject property was closed in 1969, and subsequent ownership passed through several parties from 1969 through 1997. Previous owners dismantled and removed most of the structures for scrap metal and the site remained idle until The Dow Chemical Company and subsidiaries of The Cleveland-Cliffs Iron Company and Georgia-Pacific Corporation reacquired the property and performed environmental mitigation on a portion of the subject property prior to selling the majority of the site to the city of Marquette, Michigan in 1997, which included property deed restrictions and environmental liability indemnification of the selling parties. We have been advised that there may be additional contamination located beyond the property boundaries of the portion sold to Marquette, Michigan that may have originated from historical operations of the wood chemical refining facility. It is reasonably likely that we and other potentially responsible parties could be requested or required to further investigate and potentially to remediate if warranted. We do not yet possess sufficient information to reasonably determine if, or the extent to which, remediation may be required or to reasonably estimate any potential cost to us.
NO2 and SO2 NAAQS
During the first half of 2010, EPA promulgated rules that required each state to use a combination of air quality monitoring and computer modeling to determine each state's attainment classification status against new one-hour NO2 and SO2 NAAQS. During the third quarter of 2011, the EPA issued guidance to the regulated community on conducting refined air quality dispersion modeling and implementing the new NO2 and SO2 standards. In 2012, Minnesota issued Administrative Orders ("AOs") requiring taconite facilities to conduct modeling to demonstrate compliance with the NO2 and SO2 NAAQS pursuant to the Taconite Regional Haze SIP Long Term Strategy ("LTS"). Compliance with the LTS modeling demonstrations was originally set for June 2017, but Minnesota has not advanced work on its 2012 AOs and is expected to remove NAAQS modeling obligations under the LTS in light of reduction in haze emissions associated with implementation of the taconite Regional Haze FIP regulations.
All of our operations in Minnesota and Michigan are expected to be in attainment for NO2 and SO2 NAAQS without incurring additional capital investment. While we will continue to monitor these developments and assess potential impacts, we do not anticipate further capital investments will be necessary to address NO2 and SO2 NAAQS requirements at this time.
Conductivity
Conductivity, the measurement of water’s ability to conduct electricity, is a surrogate parameter that generally increases as the amount of dissolved minerals in water increases. In December 2016, EPA issued a notice soliciting public comments on its draft guidance, Field-Based Methods for Developing Aquatic Life Criteria for Specific Conductivity. In April 2017, comments were submitted by our trade associations providing objective evidence indicating the draft methodology was scientifically flawed and unfit for promulgation. EPA confirmed in October 2019 that the 2016 draft guidance was rescinded in accordance with an August 2019 EPA memorandum regarding draft guidance documents and further expressed that EPA must update the science and subject future recommended methods or criteria for conductivity to peer-review and public comment. Adoption of the previously proposed methodology is now unlikely.
Definition of “Waters of the United States” Under the Clean Water Act
EPA and Army Corps of Engineers published a final rule in October 2019 repealing the 2015 rule that was to become effective on December 23, 2019. The next step will be for the agencies to publish a final rule that will revise the definition of “waters of the United States” which is anticipated to occur in 2020. This final rule, if similar to what was proposed in the December 2018 Revised Definition of “Waters of the United States” proposed rule, is not expected to have a material negative impact to our business. We are actively participating in the rulemaking and will continue assessing the potential impacts to our operations.

12

Table of Contents

CERCLA 108(b)
In December 2016, EPA published a proposed amendment to CERCLA section 108(b) which is focused on developing financial assurance for managing hazardous substances in the hardrock mining industry. EPA had a court-mandated deadline for publication of the final rule by December 1, 2017. The proposed rule would have required hardrock mining facilities to calculate their level of financial responsibility based on a formula included in the rule, secure an instrument or otherwise self-insure for the calculated amount, demonstrate to EPA the proof of the security, and maintain the security until EPA releases facilities from the CERCLA 108(b) regulations. The iron mining industry notified EPA of several errors in the assumptions upon which EPA drafted the rule, including a mistaken reliance on reporting data from a wholly different industry sector. We also participated in developing industry specific and national trade association comments and advocating directly with EPA and the White House Office of Management & Budget to address this and other errors with goals of exempting iron ore mining from CERCLA 108(b) applicability and correcting other deficiencies with the proposed rule. On December 1, 2017 EPA signed a federal register notice of EPA's decision not to issue final regulations for financial responsibility requirements for the hardrock mining industry under section 108(b) of CERCLA because EPA determined that the risks associated with these facilities' operations are addressed by existing federal and state programs and regulations and modern industry practices. In 2018, several environmental groups filed a challenge to EPA's decision to not issue a final rule. This challenge was rejected in a July 2019 decision by the U.S. Court of Appeals for the District of Columbia upholding EPA's determination to not issue CERCLA financial responsibility regulations for the hardrock mining industry.    
Energy
Electricity
UMERC ("Upper Michigan Energy Resources Corporation"), a subsidiary of WEPC, is the sole supplier of electric power to our Tilden mine. UMERC provides 170 megawatts of electricity to Tilden at special rates that are regulated by the Michigan Public Service Commission. During August 2016, Tilden executed a new 20-year special contract with WEPC that was subsequently assigned to UMERC. Tilden commenced receiving power under the terms of this special contract on April 1, 2019.
Minnesota Power supplies electric power to the United Taconite mine. The United Taconite mine executed a new ten-year agreement with Minnesota Power that also included Northshore's Babbitt Mine. This agreement was finalized in May 2016 and was approved by the Minnesota Public Utilities Commission in November 2016.
Silver Bay Power, a wholly-owned subsidiary with a 115 megawatt power plant that is currently economically idled, historically provided the majority of Northshore’s electrical energy requirements. In May 2016, Silver Bay Power entered into an agreement with Minnesota Power to purchase roughly half of Northshore's electricity needs from Minnesota Power through 2019. Beginning September 15, 2019, Silver Bay Power began to purchase 100% of the electricity requirements of Northshore from Minnesota Power; however, under certain circumstances the parties agreed to an interconnection agreement for Silver Bay Power to provide backup power when excess generation is necessary.
Process and Diesel Fuel
We have a long-term contract providing for the transport of natural gas on the Northern Natural Gas Pipeline for our Mining and Pelletizing segment operations. Tilden has the capability of burning natural gas, coal or, to a lesser extent, oil. Northshore has the capability to burn natural gas and oil. United Taconite has the capability to burn coal, natural gas and petroleum coke. Consistent with 2019, we expect that during 2020 our Mining and Pelletizing segment operations will utilize both natural gas and coal to heat furnaces.
In our Metallics segment, we have a long-term contract providing for the transport of natural gas on the intrastate Generation Pipeline to our HBI production plant in Toledo, Ohio. The Toledo site also has access to multiple interstate pipelines, the use of which are managed through a long-term natural gas supply agreement. The HBI production plant will utilize natural gas for its process to transform DR-grade pellets into HBI.
All of our mines utilize diesel fuel mainly for our mobile fleet. Thompson Gas supplies diesel fuel to our Northshore and United Taconite mines. Our contract with Thompson Gas expired at the end of 2019, and the parties are negotiating an extension on this supply agreement. U.S. Oil, a division of U.S. Venture Inc., supplies diesel fuel to our Tilden mine under a current long-term supply agreement for Tilden's diesel fuel needs.

13

Table of Contents

Employees
Below is a summary of our employees:
 
 
December 31,
 
 
2019
 
2018
 
2017
Mining and Pelletizing segment - Salaried1
 
397

 
514

 
503

Mining and Pelletizing segment - Hourly1, 2
 
1,712

 
2,208

 
2,182

Metallics segment - Salaried
 
40

 
26

 
6

Metallics segment - Hourly
 
48

 

 

Discontinued Operations - Salaried
 

 
2

 
79

Corporate & Support Services - Salaried
 
175

 
176

 
168

Total
 
2,372

 
2,926

 
2,938

 
1 The December 31, 2018 and 2017 data includes the employees of the Hibbing mine that we managed prior to transitioning those duties to ArcelorMittal USA in August 2019.
2 Excludes employees considered on lay-off status as a result of an indefinite or temporary idle.
Hourly employees at our Michigan and Minnesota iron ore mining operations, excluding Northshore, are represented by the USW and are covered by labor agreements between the USW and our various operating entities. These labor agreements cover approximately 1,200 active USW-represented employees at our Empire and Tilden mines in Michigan, and our United Taconite mine in Minnesota and are valid through September 30, 2022. Employees at our Northshore operations are not represented by a union and are not, therefore, covered by a collective bargaining agreement.
During August 2019, our subsidiary, Cliffs Mining Company, ceased performing manager duties for the Hibbing mine and transitioned those duties to ArcelorMittal USA. In connection with the transfer of manager duties for the Hibbing mine, Hibbing employees previously employed by Cliffs Mining Company are now employed by an ArcelorMittal USA controlled group entity.
Hourly employees at our LS&I railroads in Michigan are represented by seven unions covering approximately 100 employees. These labor agreements are covered by the Railway Labor Act and are subject to reopening for bargaining in 2020.
Salaried employees at our Mining and Pelletizing segment, Metallics segment, Corporate and Support Services are not represented by a union and are not, therefore, covered by collective bargaining agreements.
Safety
Safe production is our primary core value as we continue toward achieving a zero injury culture at our facilities. We constantly monitor our safety performance and make continuous improvements to affect change. Best practices and incident learnings are shared globally to ensure each facility can administer the most effective policies and procedures for enhanced workplace safety. Progress toward achieving our objectives is accomplished through a focus on proactive sustainability initiatives, and results are measured against established industry and company benchmarks, including our company-wide Total Reportable Incident Rate ("TRIR"). During 2019, our TRIR (including contractors) was 1.11 per 200,000 man-hours worked.
Refer to Exhibit 95 Mine Safety Disclosures (filed herewith) for mine safety information required in accordance with Section 1503(a) of the Dodd-Frank Act.

14

Table of Contents

Available Information
Our headquarters are located at 200 Public Square, Suite 3300, Cleveland, Ohio 44114-2315, and our telephone number is (216) 694-5700. We are subject to the reporting requirements of the Exchange Act and its rules and regulations. The Exchange Act requires us to file reports, proxy statements and other information with the SEC.
The SEC maintains a website that contains reports, proxy statements and other information regarding issuers that file electronically with the SEC. These materials may be obtained electronically by accessing the SEC’s home page at www.sec.gov.
We use our website, www.clevelandcliffs.com, as a channel for routine distribution of important information, including news releases, investor presentations and financial information. We also make available, free of charge on our website, our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and amendments to these reports filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act, as soon as reasonably practicable after we electronically file these documents with, or furnish them to, the SEC. In addition, our website allows investors and other interested persons to sign up to receive automatic email alerts when we post news releases and financial information on our website.
We also make available, free of charge, the charters of the Audit Committee, Governance and Nominating Committee and Compensation and Organization Committee as well as the Corporate Governance Guidelines and the Code of Business Conduct and Ethics adopted by our Board of Directors. These documents are available through our investor relations page on our website at www.clevelandcliffs.com. The SEC filings are available by selecting “Financial Information” and then “SEC Filings,” and corporate governance materials are available by selecting “Corporate Governance” for the Board Committee Charters, operational governance guidelines and the Code of Business Conduct and Ethics.
References to our website or the SEC’s website do not constitute incorporation by reference of the information contained on such websites, and such information is not part of this Annual Report on Form 10-K.
Copies of the above-referenced information are also available, free of charge, by calling (216) 694-5700 or upon written request to:
Cleveland-Cliffs Inc.
Investor Relations
200 Public Square, Suite 3300
Cleveland, OH 44114-2315

15

Table of Contents

INFORMATION ABOUT OUR EXECUTIVE OFFICERS
Following are the names, ages and positions of the executive officers of the Company as of February 20, 2020. Unless otherwise noted, all positions indicated are or were held with Cleveland-Cliffs Inc.
Name
Age
Position(s) Held
Lourenco Goncalves
62
Chairman, President and Chief Executive Officer (August 2014 – present); and Chairman, President and Chief Executive Officer of Metals USA Holdings Corp., an American manufacturer and processor of steel and other metals (May 2006 – April 2013).
Clifford T. Smith
60
Executive Vice President, Chief Operating Officer (January 2019 – present); Executive Vice President, Business Development (April 2015 – December 2018); and Executive Vice President, Seaborne Iron Ore (January 2014 – April 2015).
Keith A. Koci
55
Executive Vice President, Chief Financial Officer (February 2019 – present); and Senior Vice President and Chief Financial Officer, Metals USA Holdings Corp. (2013 – February 2019).
Terry G. Fedor
55
Executive Vice President, Operations (February 2019 – present); Executive Vice President, U.S. Iron Ore (January 2014 – January 2019); and Vice President, Operations (February 2011 – January 2014).
Traci L. Forrester
48
Executive Vice President, Business Development (May 2019 – present); Vice President (January 2018 – May 2019); Deputy General Counsel & Assistant Secretary (January 2017 – May 2019); and Assistant General Counsel (August 2013 – January 2017).
James D. Graham
54
Executive Vice President (November 2014 – present); Chief Legal Officer (March 2013 – present); Secretary (March 2014 – present); and Vice President (January 2011 – October 2014).
Maurice D. Harapiak
58
Executive Vice President, Human Resources (March 2014 – present); Chief Administration Officer (January 2018 – present); and Regional Director, Human Resources - Barrick Gold of North America, a gold mining company (November 2011 – March 2014).
R. Christopher Cebula
49
Vice President, Corporate Controller & Chief Accounting Officer (February 2017 – present); and Senior Director, Corporate Financial Planning & Analysis (April 2013 – February 2017).
All executive officers serve at the pleasure of the Board. There are no arrangements or understandings between any executive officer and any other person pursuant to which an executive officer was selected to be an officer of the Company. There is no family relationship between any of our executive officers, or between any of our executive officers and any of our directors.

16

Table of Contents

Item 1A.
Risk Factors
An investment in our common shares or other securities is subject to risks inherent to our business and our industry. Described below are certain risks and uncertainties, the occurrences of which could have a material adverse effect on us. Before making an investment decision, you should consider carefully all of the risks described below together with the other information included in this report. The risks and uncertainties described below include known material risks that we face currently. Although we have extensive risk management policies, practices and procedures aimed to mitigate these risks, uncertainties may nevertheless impair our business operation. This report is qualified in its entirety by these factors.
Our ERM function provides a framework for management's consideration of risks when making strategic, financial, operational and/or project decisions. The framework is based on ISO 31000, an internationally recognized risk management standard. Management uses a consistent methodology to identify and assess risks, determine and implement risk mitigation actions, and monitor and communicate information about the Company's most significant risks. Through these processes, we have identified seven categories of risk that we are subject to: (I) economic and market, (II) regulatory, (III) financial, (IV) operational, (V) development and sustainability, (VI) human capital and (VII) risks related to the proposed Merger. The following risk factors are presented according to these key risk categories.
I.
ECONOMIC AND MARKET RISKS
Uncertainty or weaknesses in global economic conditions, reduced economic growth in China and oversupply of iron ore and excess steel or imported products could affect adversely our business.
The world price of iron ore is influenced strongly by global economic conditions, including international demand for and supply of iron ore products. In particular, the current level of international demand for raw materials used in steel production is driven largely by industrial growth in China. Uncertainty or weakness in global economic conditions, including the slowing economic growth rate in China, has resulted, and could in the future result, in decreased demand for our products and, together with oversupply of imported products, has and may continue to lead to decreased prices, resulting in lower revenue levels and decreasing margins, which have in the past and may in the future affect adversely our business and negatively impact our financial results. We are not able to predict whether the global economic conditions will improve or worsen and the impact it may have on our operations and the industry in general going forward.
The volatility of commodity prices, namely iron ore and steel, affects our ability to generate revenue, maintain stable cash flow and fund our operations, including growth and expansion projects.
Our profitability is dependent upon the price of the product that we sell to our customers and the price of the products our customers sell, namely iron ore and steel prices. The prices of iron ore and steel have fluctuated significantly in the past and are affected by factors beyond our control, including: steel inventories; changes in the productive capacity of U.S. domestic steel producers; international demand for raw materials used in steel production; rates of global economic growth, especially construction and infrastructure activity that requires significant amounts of steel; changes in the levels of economic activity in the U.S., China, India, Europe and other industrialized or developing countries; changes in China's emissions policies and environmental compliance enforcement practices; changes in production capacity of other iron ore suppliers, especially as additional supply comes online or where there is a significant increase in imports of steel into the U.S. or Europe; changes in trade laws; imposition or termination of duties, tariffs, import and export controls and other trade barriers impacting the iron ore markets; weather-related disruptions or natural disasters that may impact the global supply of iron ore; and the proximity, capacity and cost of infrastructure and transportation.
Our earnings, therefore, may fluctuate with the prices of the product we sell and of the products our customers sell. To the extent that the prices of iron ore and steel, including the Platts 62% price, hot-rolled coil steel price, Atlantic Basin pellet premium, Platts international indexed freight rates and changes in specified PPI, including those for industrial commodities, fuel and steel, significantly decline for an extended period of time, we may have to revise our operating plans, including curtailing production, reducing operating costs and capital expenditures, and discontinuing certain exploration and development programs. We also may have to take impairments on our long-lived assets and/or inventory. Sustained lower prices also could cause us to further reduce existing mineral reserves if certain reserves no longer can be economically mined or processed at prevailing prices. We may be unable to decrease our costs in an amount sufficient to offset reductions in revenues and may incur losses. These events could have a material adverse effect on us.


17

Table of Contents

If steelmakers use methods other than blast furnace production to produce steel or use other inputs, or if their blast furnaces shut down or otherwise reduce production, the demand for our current iron ore products may decrease.
Demand for our iron ore products in North America is largely determined by the operating rates for the blast furnaces of steel companies. However, not all finished steel is produced by blast furnaces; finished steel also may be produced by other methods that use scrap steel, pig iron, HBI and DRI. North American producers also can produce steel using imported iron ore products, which may reduce or eliminate the need for domestic iron ore. Future environmental restrictions on the use of blast furnaces in North America also may reduce our customers’ use of their blast furnaces. Maintenance of blast furnaces may require substantial capital expenditures and may cause prolonged outages, which may reduce demand for our pellets. Our customers may choose not to maintain, or may not have the resources necessary to maintain, their blast furnaces. If our customers use methods to produce steel that do not use domestic iron ore pellets or if environmental or maintenance issues occur, demand for our current iron ore products may decrease, which could affect adversely our sales, margins, profitability and cash flows.
Due to economic conditions and volatility in commodity prices, or otherwise, our customers could approach us about modifying their supply agreements or fail to perform under such agreements, which could impact adversely our sales, margins, profitability and cash flows.
Although we have long-term contractual commitments for a majority of our iron ore pellet sales, uncertainty in global economic conditions may impact adversely the ability of our customers to meet their obligations to us. As a result of such market volatility, our customers could approach us about modifying their supply agreements or fail to perform under such agreements. Considering our limited base of current and potential blast furnace customers, any modifications to our sales agreements or customers' failures to perform under such agreements could impact adversely our sales, margins, profitability and cash flows. For example, certain customers in the North American integrated steel industry have experienced financial difficulties from time-to-time, including going through reorganization proceedings. A loss of sales to our existing customers could have a substantial negative impact on our sales, margins, profitability and cash flows. Other potential actions by our customers could result in additional contractual disputes and could ultimately require arbitration or litigation, either of which could be time consuming and costly. Any such disputes and/or inability to renew existing contracts on favorable terms could impact adversely our sales, margins, profitability and cash flows.
Capacity expansions and limited rationalization of supply capacity within the mining industry could lead to lower or more volatile global iron ore prices, impacting our profitability.
Global growth of iron ore demand, particularly from China, and higher iron ore prices resulted in iron ore miners expanding their production capacity in recent years to increase iron ore supply. In the past, however, moderation in demand following increases in production capacity has resulted in excess supply of iron ore, causing downward pressure on prices. A return to supply capacity expansions could lead to pricing pressure which can have an adverse impact on our sales, margins, profitability and cash flows. We do not have control over corporate strategies implemented by other iron ore producers that may result in volatility of global iron ore prices.
II.
REGULATORY RISKS
We are subject to extensive governmental regulation, which imposes, and will continue to impose, potential significant costs and liabilities on us. Future laws and regulations or the manner in which they are interpreted and enforced could increase these costs and liabilities or limit our ability to produce iron ore products.
New laws or regulations, or changes in existing laws or regulations, or the manner of their interpretation or enforcement, could increase our cost of doing business and restrict our ability to operate our business or execute our strategies. This includes, among other things, changes in the interpretation of MSHA regulations, such as workplace exam rules or safety around mobile equipment, changes in the interpretation of OSHA regulations, such as standards for occupational exposure to noise and certain chemicals, the possible taxation under U.S. law of certain income from discontinued foreign operations, compliance costs and enforcement under the Dodd-Frank Act, and costs associated with the Healthcare and Education Reconciliation Act of 2010 and the regulations promulgated under these Acts and any replacements or amendments thereof. In addition, our operations are subject to various federal, state and local laws and regulations for human health and safety, air quality, water pollution, plant, wetlands, natural resources and wildlife protection, reclamation and restoration of mining properties, the discharge of materials into the environment, the effects that mining has on groundwater quality, conductivity and availability, and other related matters. Compliance with numerous governmental permits and approvals is required for our operations.
We cannot be certain that we have been or will be at all times in complete compliance with such laws, regulations, permits and approvals. If we violate or fail to comply with these laws, regulations, permits or approvals, we could be

18

Table of Contents

fined or otherwise sanctioned by regulators. Compliance with the complex and extensive laws and regulations to which we are subject imposes substantial costs on us, which could increase over time because of heightened regulatory oversight, adoption of more stringent environmental standards, and greater demand for remediation services leading to shortages of equipment, supplies and labor, as well as other factors.
Specifically, there are several notable proposed or recently enacted rulemakings or activities to which we would be subject or that would further regulate and/or tax our North American integrated steel producer customers, which may also require us or our customers to reduce or otherwise change operations significantly or incur significant additional costs, depending on their ultimate outcome. These emerging or recently enacted rules, regulations and policy guidance include, but are not limited to: trade regulations, such as the United States-Mexico-Canada Agreement and/or other trade agreements, treaties or policies; Minnesota's potential revisions to the sulfate wild rice water quality standard; evolving water quality standards for selenium and conductivity; scope of the Clean Water Act and the definition of “Waters of the United States”; Minnesota's Mercury TMDL and associated rules governing mercury air emission reductions; Climate Change and GHG Regulation; Regional Haze FIP Rule; NO2 and SO2 NAAQS; and increased administrative and legislative initiatives related to financial assurance obligations for CERCLA, mining and reclamation obligations. Such new or more stringent legislation, regulations, interpretations or orders, when enacted and enforced, could have a material adverse effect on our business, results of operations, financial condition or profitability.
Although the numerous regulations, operating permits and our management systems mitigate potential impacts to the environment, our operations inadvertently may impact the environment or cause exposure to hazardous substances, which could result in material liabilities to us.
Our operations currently use, and have used in the past, hazardous materials, and, from time to time, we have generated solid and hazardous waste. We have been, and may in the future be, subject to claims under federal, state and local laws and regulations for toxic torts, natural resource damages and other damages as well as for the investigation and clean-up of soil, surface water, sediments, groundwater and other natural resources and reclamation of properties. Such claims for damages and reclamation may arise out of current or former conditions at sites that we own, lease or operate currently, as well as sites that we or our acquired companies have owned, leased or operated, and at contaminated sites that have been owned, leased or operated by our joint venture partners. Our liability for these claims may be strict, and/or joint and several, such that we may be held responsible for more than our share of the contamination or other damages, or even for entire claims regardless of fault. We are currently subject to potential liabilities relating to investigation and remediation activities at certain sites. In addition to sites currently owned, leased or operated, these include sites where we formerly conducted raw material processing or other operations, inactive sites that we currently own, predecessor sites, acquired sites, leased land sites and third-party waste disposal sites. We may be named as a potentially responsible party at other sites in the future and we cannot be certain that the costs associated with these additional sites will not be material.
We also could be subject to litigation for alleged bodily injuries arising from claimed exposure to hazardous substances allegedly used, released, or disposed of by us. In particular, we and certain of our subsidiaries were involved in various claims relating to the exposure of asbestos and silica to seamen who sailed until the mid-1980s on the Great Lakes vessels formerly owned and operated by certain of our subsidiaries. While several hundred of these claims against us had been combined in a multidistrict litigation docket and have since been dismissed and/or settled for non-material amounts, there remains a possibility that similar types of claims could be filed in the future.
Environmental impacts as a result of our operations, including exposures to hazardous substances or wastes associated with our operations, could result in costs and liabilities that could materially and adversely affect our margins, cash flow or profitability.
We may be unable to obtain and/or renew permits necessary for our operations or be required to provide additional financial assurance, which could reduce our production, cash flows, profitability and available liquidity. We also could face significant permit and approval requirements that could delay our commencement or continuation of new or existing production operations which, in turn, could affect materially our profitability and available liquidity.
Prior to commencement of mining and periodically after production begins, we must submit to and obtain approval from the appropriate regulatory authority of plans showing where and how mining and reclamation operations are to occur. These plans must include information such as the location of mining areas, stockpiles, surface waters, haul roads, tailings basins and drainage from mining operations. Any requirements imposed by any such authority may be costly and time-consuming and may delay commencement or continuation of exploration or production operations.

19

Table of Contents

Mining and manufacturing companies must obtain numerous permits that impose strict conditions on various environmental and safety matters in connection with iron ore mining and production. These include permits issued by various federal, state and local agencies and regulatory bodies. The permitting rules are complex and may change over time, making our ability to comply with the applicable requirements more difficult or impractical and costly, possibly precluding the continuance of ongoing operations or the development of future operations. Interpretations of rules may also change over time and may lead to requirements, such as additional financial assurance, making it costlier to comply. The public, including special interest groups and individuals, have certain rights under various statutes to comment upon, submit objections to, and otherwise engage in the permitting process, including bringing citizens’ lawsuits to challenge such permits or activities. Accordingly, required permits may not be issued or renewed in a timely fashion (or at all), or permits issued or renewed may be conditioned in a manner that may restrict our ability to conduct our mining and production activities efficiently, including the requirement for additional financial assurances that we may not be able to provide on commercially reasonable terms (or at all) and which would further limit our borrowing base under our ABL Facility. Such inefficiencies could reduce our production, cash flows, profitability or available liquidity.
III.
FINANCIAL RISKS
A substantial majority of our sales are made under supply agreements with specified duration to a low number of customers that contain price-adjustment clauses that could adversely affect our profitability.
A majority of our Mining and Pelletizing sales are made under supply agreements with specified durations to a limited number of customers. For the year ended December 31, 2019, approximately 99% of our revenues from product sales and services was derived from the North American integrated steel industry, and three customers together accounted for 97% of our Mining and Pelletizing product sales revenues. Our average remaining duration of our Mining and Pelletizing contracts as of December 31, 2019 is approximately five years. Pricing under our customer contracts is adjusted by certain factors, including Platts 62% price, hot-rolled coil steel price, Atlantic Basin pellet premium, Platts international indexed freight rates and changes in specified PPI, including those for industrial commodities, fuel and steel. As a result of these and other pricing constructs contained in our customer contracts, our financial results are sensitive to changes in iron ore and steel prices.
Our existing and future indebtedness may limit cash flow available to invest in the ongoing needs of our business, which could prevent us from fulfilling our obligations under our senior notes and ABL Facility.
As of December 31, 2019, we had $2,238.0 million aggregate principal amount of long-term debt outstanding, $400.0 million of which was secured (excluding $37.9 million of outstanding letters of credit and $38.2 million of finance leases), and $352.6 million of cash on our balance sheet. As of December 31, 2019, no loans were drawn under the ABL Facility and we had total availability of $395.7 million as a result of borrowing base limitations. As of December 31, 2019, the principal amount of letters of credit obligations and other commitments totaled $37.9 million, thereby further reducing available borrowing capacity on our ABL Facility to $357.8 million.
Our existing level of indebtedness requires us to dedicate a portion of our cash flow from operations to the payment of debt service, reducing the availability of our cash flow to fund capital expenditures, acquisitions or strategic development initiatives, and other general corporate purposes. Moreover, our level of indebtedness could have further consequences, including increasing our vulnerability to adverse economic or industry conditions, limiting our ability to obtain additional financing in the future to enable us to react to changes in our business, or placing us at a competitive disadvantage compared to businesses in our industry that have less indebtedness.
Although we were successful in financing our HBI project, our indebtedness could limit our ability to obtain additional financing on acceptable terms or at all for working capital, capital expenditures, acquisitions or strategic development initiatives, and general corporate purposes. Our liquidity needs could vary significantly and may be affected by general economic conditions, industry trends and many other factors not within our control. If we are unable to generate sufficient cash flow from operations in the future to service our debt, we may be required to refinance all or a portion of our existing debt. In addition, in connection with the consummation of the Merger, we expect to incur additional debt to, among other things, retire certain of AK Steel's existing debt and enter into the New ABL Facility. See "—VII. Risks Related to the Proposed Merger—Following completion of the proposed Merger, our debt may limit our financial flexibility."
Any failure to comply with covenants in the instruments governing our debt could result in an event of default which, if not cured or waived, would have a material adverse effect on us.

20

Table of Contents

We may not be able to generate sufficient cash to service all of our debt, and may be forced to take other actions to satisfy our obligations under our debt, which may not be successful.
Our ability to make scheduled payments on or to refinance our debt obligations depends on our ability to generate cash in the future and our financial condition and operating performance, which are subject to prevailing economic and competitive conditions and to certain financial, business and other factors beyond our control. We cannot assure you that we will maintain a level of cash flows from operating activities sufficient to permit us to pay the principal, premium, if any, and interest on our debt.
We also have significant capital requirements, including interest payments to service our debt. If we incur significant losses in future periods, we may be unable to continue as a going concern. If we are unable to continue as a going concern, we may consider, among other options, restructuring our debt; however, there can be no assurance that these options will be undertaken and, if so undertaken, whether these efforts would succeed.
If our cash flows and capital resources are insufficient to fund our debt service obligations, we could face substantial liquidity problems and we may be forced to reduce or delay investments and capital expenditures, or to sell assets, seek additional capital, including additional secured or unsecured debt, or restructure or refinance our debt. We may be unable to consummate any proposed asset sales or recover the carrying value of these assets, and any proceeds may not be adequate to meet any debt service obligations then due. Any refinancing of our debt could be at higher interest rates and may require us to comply with more onerous covenants, making it more difficult to obtain surety bonds, letters of credit or other financing, particularly during periods in which credit markets are weak. Further, we may need to refinance all or a portion of our debt on or before maturity, and we may not be able to refinance any of our debt on commercially reasonable terms or at all, causing a change in our credit ratings; limiting our ability to compete with companies that are not as leveraged and that may be better positioned to withstand economic downturns; and limiting our flexibility in planning for, or reacting to, and increasing our vulnerability to, changes in our business, the industry in which we compete and general economic and market conditions. In addition, new or increased financial assurances may be demanded by our vendors or regulatory agencies that we may not be able to provide on commercially reasonable terms or at all.
Any of these examples potentially could have a material adverse impact on our results of operations, profitability, shareholders' equity and capital structure.
A court or regulatory body could find that we are responsible, in whole or in part, for liabilities we transferred to third party purchasers.
As part of our strategy to protect our core business, we have sold or otherwise disposed of several non-core assets, such as our North American Coal and Australian assets. Some of the transactions under which we sold or otherwise disposed of our non-core assets included provisions transferring certain liabilities to the purchasers or acquirers of those non-core assets. While we believe that all such transfers were completed properly and are legally binding, if the purchaser fails to fulfill its obligations, we may be at risk that some court or regulatory body could disagree and determine that we remain responsible for liabilities we intended to and did transfer.
Our ability to collect payments from our customers depends on their creditworthiness.
Our ability to receive payment for products sold and delivered to our customers depends on the creditworthiness of our customers. Generally, we deliver our products to our customers’ facilities in advance of payment for those products. Under this practice for most of our customers, title and risk of loss do not pass to the customer until we receive payment; however, there is typically a period of time in which our products, for which we have reserved title, are within our customers’ control. Where we have identified credit risk with certain customers, we have put in place alternate payment terms from time to time.
Customers outside of the U.S. may be subject to pressures and uncertainties that may affect their ability to pay, including trade barriers, exchange controls, and local economic and political conditions. Downturns in the economy and disruptions in the global financial markets have affected the creditworthiness of our customers from time to time. Some of our customers are highly leveraged. If economic conditions worsen or prolonged global, national or regional economic recession conditions return, it is likely to impact significantly the creditworthiness of our customers and could, in turn, increase the risk we bear on payment default for the credit we provide to our customers and could limit our ability to collect receivables. Failure to receive payment from our customers for products that we have delivered could affect adversely our results of operations, financial condition and liquidity.

21

Table of Contents

Our operating expenses could increase significantly if the price of electrical power, fuel or other energy sources increases.
Our operations require significant use of energy. Energy expenses, which are approximately 15% to 25% of our total production costs, are sensitive to changes in electricity prices and fuel prices, including diesel fuel and natural gas prices. Prices for electricity, natural gas and fuel oils can fluctuate widely with availability and demand levels from other users. During periods of peak usage, supplies of energy may be curtailed and we may not be able to purchase them at historical rates. A disruption in the transmission of energy, inadequate energy transmission infrastructure, or the termination of any of our energy supply contracts could interrupt our energy supply and affect adversely our operations. While we have some long-term contracts with electrical suppliers, we are exposed to fluctuations in energy costs that can affect our production costs. As an example, our United Taconite mine is subject to changes in Minnesota Power’s rates, such as periodic rate changes that are reviewed and approved by the state public utilities commission in response to an application filed by Minnesota Power. We also enter into market-based pricing supply contracts for electricity, natural gas and diesel fuel for use in our operations. Those contracts expose us to price increases in energy costs, which could cause our profitability to decrease significantly. In addition, U.S. public utilities may pass through additional capital and operating cost increases to their customers related to new or pending U.S. environmental regulations that may require significant capital investment and use of cleaner fuels in the future.
Changes in credit ratings issued by nationally recognized statistical rating organizations could adversely affect our cost of financing and the market price of our securities.
Credit rating agencies could downgrade our ratings due to various developments, including the Merger, factors specific to our business, a prolonged cyclical downturn in the mining or steel industry, or macroeconomic trends (such as global or regional recessions) and trends in credit and capital markets more generally. Any decline in our credit ratings may result in an increase to our cost of future financing and/or limit our access to the capital markets, which could harm our financial condition and results of operations, hinder our ability to refinance existing indebtedness on acceptable terms, have an adverse effect on the market price of our securities and may affect adversely the terms under which we purchase goods and services.
Our actual operating results may differ significantly from our guidance.
From time to time, we release guidance, including that set forth under “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Outlook” in our Annual Reports on Form 10-K and our Quarterly Reports on Form 10-Q, regarding our future performance. This guidance, which consists of forward-looking statements, is prepared by our management and is qualified by, and subject to, the assumptions and the other information included in our Annual Reports on Form 10-K and our Quarterly Reports on Form 10-Q. Our guidance is not prepared with a view toward compliance with published guidelines of the American Institute of Certified Public Accountants, and neither our independent registered public accounting firm nor any other independent or outside party compiles or examines the guidance and, accordingly, no such person expresses any opinion or any other form of assurance with respect thereto.
Guidance is based upon a number of assumptions and estimates that, while presented with numerical specificity, are inherently subject to business, economic and competitive uncertainties and contingencies, many of which are beyond our control and are based upon specific assumptions with respect to future business decisions, some of which will change. The principal reason that we release such data is to provide a basis for our management to discuss our business outlook with analysts and investors. We do not accept any responsibility for any projections or reports published by any such third parties.
Guidance is necessarily speculative in nature, and it can be expected that some or all of the assumptions of the guidance furnished by us will not materialize or will vary significantly from actual results. Accordingly, our guidance is only an estimate of what management believes is realizable as of the date of release. Actual results will vary from the guidance. Investors should also recognize that the reliability of any forecasted financial data diminishes the further in the future that the data are forecast. In light of the foregoing, investors are urged to put the guidance in context and not to place undue reliance on it.
Any failure to successfully implement our operating strategy or the occurrence of any of the risks described in our Annual Reports on Form 10-K or our Quarterly Reports on Form 10-Q could result in actual operating results being different than the guidance, and such differences may be adverse and material.
Our assets as of December 31, 2019 include a deferred tax asset, the full value of which we may not be able to realize.

22

Table of Contents

We recognize deferred tax assets and liabilities based on differences between the financial statement carrying amounts and the tax basis of assets and liabilities. At December 31, 2019, the net deferred tax asset was $459.5 million, primarily related to U.S. net operating loss carryforwards.  We regularly review our deferred tax assets for recoverability based on our history of earnings, expectations for future earnings and expected timing of reversals of temporary differences. Realization of deferred tax assets ultimately depends on the existence of sufficient taxable income. We believe the recorded net deferred tax asset at December 31, 2019 is fully realizable based on our expected future earnings.  However, our assumptions and estimates are inherently subject to business, economic and competitive uncertainties and contingencies, many of which are beyond our control and some of which may change. As a result, we could ultimately lose a portion of our deferred tax asset related to net operating loss carryforwards due to expiration, which could have a material adverse effect on our results of operations and cash flows.
Holders of our common shares may not receive dividends on their common shares.

Holders of our common shares are entitled to receive only such dividends as our Board of Directors may from time to time declare out of funds legally available for such payments. We are incorporated in Ohio and governed by the Ohio General Corporation Law, which allows a corporation to pay dividends, in general, in an amount that cannot exceed its surplus, as determined under Ohio law. Our ability to pay dividends will be subject to our future earnings, capital requirements and financial condition, as well as our compliance with covenants and financial ratios related to existing or future indebtedness, business prospects and other factors that our Board of Directors may deem relevant. Additionally, our ABL Facility contains, and agreements governing any of our future debt (including the New ABL Facility) may contain, covenants and other restrictions that, in certain circumstances, could limit the level of dividends that we are able to pay on our common shares. Although we recently have declared cash dividends on our common shares, we are not required to declare cash dividends on our common shares and our Board of Directors may reduce, defer or eliminate our common share dividend in the future.
We rely on our joint venture partners to meet their payment obligations and we are subject to risks involving the acts or omissions of our joint venture partners.
We co-own one of our four operating Mining and Pelletizing mines with ArcelorMittal USA and U.S. Steel. One of our joint venture partners is also our customer. We cannot control the actions of our joint venture partners, and we have limited ability to control the joint venture because we hold a minority interest and no longer manage the joint venture. Accordingly, we rely on our joint venture partners to make their required capital contributions and to pay for their share of the iron ore produced. If one or both of our joint venture partners fail to perform their obligations, the remaining joint venture partners, including ourselves, may be required to assume additional material obligations, including significant capital contributions, costs of environmental remediation, and pension and OPEB obligations.
IV.
OPERATIONAL RISKS
Mine closures entail substantial costs. If we prematurely close one or more of our mines, our results of operations and financial condition would likely be affected adversely.
If we prematurely close any of our mines, our production and revenues would be reduced unless we were able to increase production at our other mines in an offsetting amount, which may not be possible. The closure of a mining operation involves significant fixed closure costs, including accelerated employment legacy costs, severance-related obligations, reclamation and other environmental costs, and the costs of terminating long-term obligations, including customer, energy and transportation contracts and equipment leases. We base our assumptions regarding the life of our mines on detailed studies we perform from time to time, but those studies and assumptions are subject to uncertainties and estimates that may not be accurate. We recognize the costs of reclaiming open pits, stockpiles, tailings ponds, roads and other mining support areas based on the estimated mining life of our property. If we were to significantly reduce the estimated life of any of our mines, the mine-closure costs would be applied to a shorter period of production, which would increase costs per ton produced and could significantly and adversely affect our results of operations and financial condition.
A permanent mine closure could accelerate and significantly increase employment legacy costs, including our expense and funding costs for pension and OPEB obligations. A number of employees would be eligible for immediate retirement under special eligibility rules that apply upon a mine closure. All employees eligible for immediate retirement under the pension plans at the time of the permanent mine closure also could be eligible for OPEB, thereby accelerating our obligation to provide these benefits. Certain mine closures would precipitate a pension closure liability significantly greater than an ongoing operation liability and may trigger certain severance liability obligations.

23

Table of Contents

Our sales and competitive position depend on the ability to transport our products to our customers at competitive rates and in a timely manner.
Disruption of the lake, rail and trucking transportation services because of weather-related problems, including ice and winter weather conditions on the Great Lakes or St. Lawrence Seaway, climate change, strikes, lock-outs, or other events and lack of alternative transportation options, could impair our ability to supply iron ore products to our customers at competitive rates or in a timely manner and, thus, could adversely affect our sales, margins and profitability. Further, reduced dredging and environmental changes, particularly at Great Lakes ports, could impact negatively our ability to move our iron ore products because lower water levels restrict the tonnage that vessels can haul, resulting in higher freight rates.
Natural disasters, weather conditions, disruption of energy, unanticipated geological conditions, equipment failures, and other unexpected events may lead our customers, our suppliers or our facilities to curtail production or shut down operations.
Operating levels within our industry are subject to unexpected conditions and events that are beyond the industry’s control. Those events could cause industry members or their suppliers to curtail production or shut down a portion or all of their operations, which could reduce the demand for our iron ore products and affect adversely our sales, margins and profitability.
Interruptions in production capabilities inevitably will increase our production costs and reduce our profitability. For example, we do not have meaningful excess capacity for current production needs, and we are not able to quickly increase production or restart production at one mine to offset an interruption in production at another mine. Additionally, restart production costs can be even higher if required to be taken during extremely cold weather conditions.
A portion of our production costs are fixed regardless of current operating levels. As noted, our operating levels are subject to conditions beyond our control that can delay deliveries or increase the cost of production for varying lengths of time. These include weather conditions (for example, extreme winter weather, tornadoes, floods, and the lack of availability of process water due to drought) and natural and man-made disasters, tailings dam failures, pit wall failures, unanticipated geological conditions, including variations in the amount of rock and soil overlying the deposits of iron ore, variations in rock and other natural materials, and variations in geologic conditions and ore processing changes.
Our mining operations, ore processing facilities and logistics operations depend on critical pieces of equipment. This equipment may, on occasion, be out of service because of unanticipated failures. In addition, all of our mines and most of our processing facilities have been in operation for several decades, and the equipment is aged. In the future, we may experience additional lengthy shutdowns or periods of reduced production because of equipment failures. Further, remediation of any interruption in production capability may require us to make large capital expenditures that could have a negative effect on our profitability and cash flows. Our business interruption insurance would not cover all of the lost revenues associated with equipment failures. Longer-term business disruptions could result in a loss of customers, which could adversely affect our future sales levels and profitability.
Many of our mines and facilities are dependent on one source for electric power and for natural gas. A significant interruption in service from our energy suppliers due to terrorism or sabotage, weather conditions, natural disasters, or any other cause could result in substantial losses that may not be fully recoverable, either from our business interruption insurance or responsible third parties.
We incur certain costs when production capacity is idled, including increased costs to resume production at idled facilities and costs to idle facilities.
Our decisions concerning which facilities to operate and at what capacity levels are made based upon our customers' orders for products, as well as the quality, performance capabilities and production cost of our operations. During depressed market conditions, we may concentrate production at certain facilities and not operate others in response to customer demand, and as a result we may incur idle facility costs. In 2016, for example, two of our Minnesota mines were temporarily idled for a portion of the year, and we indefinitely idled the Empire mine in Michigan in August 2016.

24

Table of Contents

When we restart idled facilities, we incur certain costs to replenish inventories, prepare the previously idled facilities for operation, perform the required mine stripping, repair and maintenance activities, and prepare employees to return to work safely and to resume production responsibilities. The amount of any such costs can be material, depending on a variety of factors, such as the period of idle time, necessary repairs and available employees, and is difficult to project.
If faced with overcapacity in the iron ore market, we may seek to rationalize assets through asset sales, temporary shutdowns, indefinite idles or facility closures.
We may not have adequate insurance coverage for some business risks.
As noted above, our operations are generally subject to a number of hazards and risks, which could result in damage to, or destruction of, equipment, properties or facilities. The insurance that we maintain to address risks that are typical in our business may not provide adequate coverage. Insurance against some risks, such as liabilities for environmental pollution, tailings basin breaches, or certain hazards or interruption of certain business activities, may not be available at an economically reasonable cost, or at all. Even if available, we may self-insure where we determine it is most cost-effective to do so. As a result, accidents or other negative developments involving our mining, production or transportation activities could have a material adverse effect on our operations.
A disruption in, or failure of our information technology systems, including those related to cybersecurity, could adversely affect our business operations and financial performance.
We rely on the accuracy, capacity and security of our information technology (“IT”) systems for the operations of many of our business processes and to comply with regulatory, legal and tax requirements. While we maintain some of our critical information technology systems, we are also dependent on third parties to provide important IT services relating to, among other things, operational technology at our facilities, human resources, electronic communications and certain finance functions. Despite the security measures that we have implemented, including those related to cybersecurity, our systems could be breached or damaged by computer viruses, natural or man-made incidents or disasters, or unauthorized physical or electronic access. Though we have controls in place, we cannot provide assurance that a cyber-attack will not occur. Furthermore, we may have little or no oversight with respect to security measures employed by third-party service providers, which may ultimately prove to be ineffective at countering threats. Failures of our IT systems, whether caused maliciously or inadvertently, may result in the disruption of our business processes, or in the unauthorized release of sensitive, confidential or otherwise protected information, or result in the corruption of data, which could adversely affect our business operations and financial performance. In addition, we may be required to incur significant costs to protect against and, if required, remediate the damage caused by such disruptions or system failures in the future.
Our profitability could be affected adversely by the failure of outside contractors and/or suppliers to perform.
We rely on outside companies to provide key services, including the design and construction of our HBI production plant in Toledo, Ohio. Additionally, we use contractors to help complete certain capital projects, such as upgrades to our existing Mining and Pelletizing facilities. A contractor's or supplier's failure to perform could affect adversely our production, sales, and our ability to fulfill customer requirements. Such failure to perform in a significant way would result in additional costs for us, which also could affect adversely our production rates, sales, results of operations and profitability.
V.
DEVELOPMENT AND SUSTAINABILITY RISKS
The cost and time to implement a strategic capital project may prove to be greater than originally anticipated.
We undertake strategic capital projects, such as the HBI project, in order to enhance, expand or upgrade our mining and production capabilities or diversify our customer base. Our ability to achieve the anticipated production volumes, revenues or otherwise realize acceptable returns on strategic capital projects that we may undertake is subject to a number of risks, many of which are beyond our control, including a variety of market (such as a volatile pricing environment for iron ore products), operational, permitting and labor-related factors. Further, the cost to implement any given strategic capital project ultimately may prove to be greater and may take more time than originally anticipated. Inability to achieve the anticipated results from the implementation of our strategic capital projects, incurring unanticipated implementation costs or penalties, or the inability to meet contractual obligations could affect adversely our results of operations and future earnings and cash flow generation.
We continually must replace ore reserves depleted by production. Exploration activities may not result in additional discoveries.
Our ability to replenish our ore reserves is important to our long-term viability. Depleted ore reserves must be

25

Table of Contents

replaced by further delineation of existing ore bodies or by locating new deposits in order to maintain production levels over the long term. For example, in 2017 we made investments in our Tilden and Empire mines and in land in Minnesota to provide future potential ore reserves. Based on the economic reserve analyses performed during 2019 and 2018, we revised the mine plans for Tilden and Northshore, respectively, to add ore reserves and extend mine life. Resource exploration and development are highly speculative in nature. Exploration projects involve many risks, require substantial expenditures and may not result in the discovery of sufficient additional mineral deposits that can be mined profitably. Once a site with mineralization is discovered, it may take several years from the initial phases of drilling until production is possible, during which time the economic feasibility of production may change. Substantial expenditures are required to establish recoverable proven and probable reserves and to construct mining and processing facilities. As a result, there is no assurance that current or future exploration programs will be successful, and there is a risk that depletion of reserves will not be offset by discoveries or acquisitions.
We rely on estimates of our recoverable reserves, which is complex due to geological characteristics of the properties and the number of assumptions made.
We regularly evaluate our iron ore reserves based on revenues and costs and update them as required in accordance with SEC Industry Guide 7. We anticipate further updating our mining properties disclosure in accordance with the SEC's Final Rule 13-10570, Modernization of Property Disclosures for Mining Registrants, which became effective February 25, 2019, and which rescinds Industry Guide 7 following a two-year transition period, which means that we will be required to comply with the new rule no later than our fiscal year beginning January 1, 2021. Estimates of reserves and future net cash flows necessarily depend upon a number of variable factors and assumptions, some of which are beyond our control, such as production capacity, effects of regulations by governmental agencies, future prices for iron ore, future industry conditions and operating costs, severance and excise taxes, development costs and costs of extraction and reclamation, all of which may vary considerably from actual results. Estimating the quantity and grade of reserves requires us to determine the size, shape and depth of our mineral bodies by analyzing geological data, such as samplings of drill holes. In addition to the geology assumptions regarding our mines, assumptions are also required to determine the economic feasibility of mining these reserves, including estimates of future commodity prices and demand, the mining methods we use, and the related costs incurred to develop and mine our reserves. For these reasons, estimates of the economically recoverable quantities of mineralized deposits attributable to any particular group of properties, classifications of such reserves based on risk of recovery and estimates of future net cash flows prepared by different engineers or by the same engineers at different times may vary substantially as the criteria change. Estimated ore reserves could be affected by future industry conditions, future changes in the SEC's mining property disclosure requirements, geological conditions and ongoing mine planning. Actual volume and grade of reserves recovered, production rates, revenues and expenditures with respect to our reserves will likely vary from estimates, and if such variances are material, our sales and profitability could be affected adversely.
Defects in title or loss of any leasehold interests in our mining properties could limit our ability to mine these properties or result in significant unanticipated costs.
A portion of our mining operations are conducted on properties we lease, license or as to which we have easements or other possessory interests, which we refer to as "leased properties." Consistent with industry practice, title to most of these leased properties and mineral rights are not usually verified until we make a commitment to develop a property, which may not occur until after we have obtained necessary permits and completed exploration of the leased property. In some cases, title with respect to leased properties is not verified at all because we instead rely on title information or representations and warranties provided by lessors or grantors. We do not maintain title insurance on our owned or leased properties. A title defect or the loss of any lease, license or easement for any leased mining property could affect adversely our ability to mine any associated reserves. In addition, from time to time the rights of third parties for competing uses of adjacent, overlying, or underlying lands such as for roads, easements and public facilities may affect our ability to operate as planned if our title is not superior or arrangements cannot be negotiated.
Any challenge to our title could delay the exploration and development of some reserves, deposits or surface rights, cause us to incur unanticipated costs and could ultimately result in the loss of some or all of our interest in those reserves or surface rights. In the event we lose reserves, deposits or surface rights, we may have to shut down or significantly alter the sequence of our mining operations, which may affect adversely our future production, revenues and cash flows. Additionally, if we lose any leasehold interests relating to any of our pellet plants or loadout facilities, we may need to find an alternative location to process our iron ore and load it for delivery to customers, which could result in significant unanticipated costs. Finally, we could incur significant liability if we inadvertently mine on property we do not own or lease.

26

Table of Contents

In order to continue to foster growth in our business and maintain stability of our earnings, we must maintain our social license to operate with our stakeholders.
Maintaining a strong reputation and consistent operational and safety track record is vital in order to continue to foster growth and maintain stability in our earnings. As sustainability expectations increase and regulatory requirements continue to evolve, maintaining our social license to operate becomes increasingly important. We incorporate social license expectations in our ERM program. Our ability to maintain our reputation and strong operating track record could be threatened, including by circumstances outside of our control, such as disasters caused or suffered by other companies in our industry. If we are not able to respond effectively to these and other challenges to our social license to operate, our reputation could be damaged significantly. Damage to our reputation could affect adversely our operations and ability to foster growth projects.
Estimates and timelines relating to new development projects are uncertain and we may incur higher costs and lower economic returns than estimated.
Mining industry development projects typically require a number of years and significant expenditures before production is possible. Such projects could experience unexpected problems and delays during development, construction and/or start-up.
Our decision to develop a project typically is based on the results of feasibility studies, which estimate the anticipated economic returns of a project. The actual project profitability or economic feasibility may differ from such estimates as a result of any of the following factors, among others: changes in tonnage, grades and metallurgical characteristics of ore or other raw materials to be mined and processed; estimated future prices of the relevant product; changes in customer demand; higher construction and infrastructure costs; the quality of the data on which engineering assumptions were made; higher production costs; adverse geotechnical conditions; availability of adequate labor force; availability and cost of water and energy; availability and cost of transportation; fluctuations in inflation and currency exchange rates; availability and terms of financing; delays in obtaining environmental or other government permits or changes in laws and regulations including environmental laws and regulations; weather or severe climate impacts; and potential delays relating to social and community issues.
Our HBI project will require the commitment of substantial resources. Any unanticipated costs or delays associated with our HBI project could have a material adverse effect on our financial condition or results of operations.
Our ongoing efforts with respect to our HBI project require the commitment of substantial capital expenditures. We currently expect to incur capital expenditures through 2020 of approximately $830 million plus a contingency of up to 20%, excluding capitalized interest, on the development of the HBI production plant in Toledo, Ohio, of which approximately $700 million was paid as of December 31, 2019. Our estimated expenses may increase as personnel and equipment associated with advancing development and commercial production are added. The timely completion and successful commercial startup of the HBI project will depend in part on the following:
maintaining required federal, state and local permits;
completing construction work, commissioning and integration of all of the systems comprising our HBI production plant;
negotiating sales contracts for our planned production; and
other factors, many of which are beyond our control.
Any unanticipated costs or delays associated with our HBI project could have a material adverse effect on our financial condition or results of operations and could require us to seek additional capital, which may not be available on commercially acceptable terms or at all.
VI.
HUMAN CAPITAL RISKS
Our profitability could be affected adversely if we fail to maintain satisfactory labor relations.
Production in our mines and processing facilities is dependent upon the efforts of our employees. We are party to labor agreements with various labor unions that represent employees at some of our operations. Such labor agreements are negotiated periodically, and, therefore, we are subject to the risk that these agreements may not be able to be renewed on reasonably satisfactory terms. It is difficult to predict what issues may arise as part of the collective bargaining process, and whether negotiations concerning these issues will be successful. Due to union activities or other employee actions,

27

Table of Contents

we could experience labor disputes, work stoppages or other disruptions in our production of iron ore that could affect us adversely. The USW represents all hourly employees at United Taconite and Tilden mines. Our labor agreements with the USW were ratified in October 2018 and extended for a four-year term, effective as of October 1, 2018.
If we enter into a new labor agreement with any union that significantly increases our labor costs relative to our competitors or fail to come to an agreement upon expiry, our ability to compete may be materially and adversely affected.
We may encounter labor shortages for critical operational positions, which could affect adversely our ability to produce our products.
We are predicting a long-term shortage of skilled workers for the mining and metals processing industries, and competition for the available workers limits our ability to attract and retain employees as well as engage third-party contractors. As our experienced employees retire, we may have difficulty replacing them at competitive wages.
Our expenditures for pension and OPEB obligations could be materially higher than we have predicted if our underlying assumptions differ from actual outcomes, there are mine closures, or our joint venture partners fail to perform their obligations that relate to employee pension plans.
We provide defined benefit pension plans and OPEB to certain eligible union and non-union employees, including our share of expense and funding obligations with respect to our unconsolidated joint venture. Our pension and OPEB expenses and our required contributions to our pension and OPEB plans are affected directly by the value of plan assets, the projected and actual rate of return on plan assets, and the actuarial assumptions we use to measure our defined benefit pension plan obligations, including the rate at which future obligations are discounted.
We cannot predict whether changing market or economic conditions, regulatory changes or other factors will increase our pension and OPEB expenses or our funding obligations, diverting funds we would otherwise apply to other uses.
We have calculated our unfunded pension and OPEB obligations based on a number of assumptions. If our assumptions do not materialize as expected, cash expenditures and costs that we incur could be materially higher. Moreover, we cannot be certain that regulatory changes will not increase our obligations to provide these or additional benefits. These obligations also may increase substantially in the event of adverse medical cost trends or unexpected rates of early retirement, particularly for bargaining unit retirees.
We depend on our senior management team and other key employees, and the loss of these employees could adversely affect our business.
Our success depends in part on our ability to attract and motivate our senior management and key employees. Achieving this objective may be difficult due to a variety of factors, including fluctuations in the global economic and industry conditions, competitors’ hiring practices, cost reduction activities, and the effectiveness of our compensation programs. Competition for qualified personnel can be intense. We must continue to recruit, retain, and motivate our senior management and key personnel in order to maintain our business and support our projects. A loss of senior management and key personnel could prevent us from capitalizing on business opportunities, and our operating results could be adversely affected.
VII.
RISKS RELATED TO THE PROPOSED MERGER
The Merger Agreement may be terminated in accordance with its terms and the Merger may not be completed.
The Merger Agreement contains a number of conditions that must be satisfied or waived in order to complete the Merger. Those conditions include, among others:
the adoption of the Merger Agreement by AK Steel stockholders;
the approval by our shareholders of the Merger Agreement and the transactions contemplated by the Merger Agreement, including the issuance of our common shares in connection with the Merger;
the receipt of required regulatory approval in Mexico;
the absence of any governmental order or law prohibiting the consummation of the Merger;
the accuracy of our and AK Steel’s respective representations and warranties under the Merger Agreement (subject to the materiality standards set forth in the Merger Agreement);

28

Table of Contents

the performance by us and AK Steel of our respective obligations under the Merger Agreement in all material respects; and
the absence of a material adverse effect (as described in the Merger Agreement) on us or AK Steel.
These conditions to the closing of the Merger may not be fulfilled in a timely manner or at all, and, accordingly, the Merger may be delayed or may not be completed.
In addition, if the Merger is not completed by June 30, 2020 (subject to the parties each being entitled to extend the date to September 30, 2020 and then December 31, 2020 if required antitrust approvals have not yet been obtained or there is an impediment under any antitrust law), either party may choose not to proceed with the Merger. The parties can mutually decide to terminate the Merger Agreement at any time, before or after the receipt of AK Steel stockholder approval or our shareholder approval.
Failure to complete the Merger could negatively impact the price of our common shares as well as our future business and financial results.
If the Merger is not completed for any reason, including the failure of our shareholders to approve the Merger Agreement and the transactions contemplated by the Merger Agreement, including the issuance of our common shares in connection with the Merger, or the failure of AK Steel stockholders to adopt the Merger Agreement, our business and financial results may be adversely affected, including as follows:
we may experience negative reactions from the financial markets, including negative impacts on the market price of our common shares;
the manner in which customers, vendors, business partners and other third parties perceive us may be negatively impacted, which in turn could affect our ability to compete for new business or obtain renewals in the marketplace more broadly;
we may experience negative reactions from employees, which may adversely affect, among other things, productivity and occupational safety; and
we will have expended significant time and resources that could otherwise have been spent on our existing businesses and the pursuit of other opportunities that could have been beneficial to us, and our ongoing business and financial results may be adversely affected.
If the Merger Agreement is terminated under specified circumstances, we may be required to pay AK Steel a termination fee.
We are subject to business uncertainties while the Merger is pending, which could adversely affect our business.
Uncertainty about the effect of the Merger on employees, suppliers and customers may have an adverse effect on us. These uncertainties may impair our ability to attract, retain and motivate key personnel until the Merger is completed and for a period of time thereafter, and could cause our suppliers, customers and others that deal with us to seek to change their existing business relationships with us. For example, our steelmaking customers may not want to purchase their iron ore from a company that is also a competitor.
The Merger may be less accretive than expected, or may be dilutive, to our earnings per share, which may negatively affect the market price of our common shares.
The Merger may be less accretive than expected, or may be dilutive, to our earnings per share. Estimates of our earnings per share in the future are based on preliminary estimates that may materially change. In addition, future events and conditions could decrease or delay any accretion, result in dilution or cause greater dilution than is currently expected, including:
adverse changes in market conditions;
commodity prices for iron ore and steel;
production levels;
operating results;
competitive conditions;

29

Table of Contents

laws and regulations affecting the iron ore and steel businesses;
capital expenditure obligations;
higher than expected integration costs;
lower than expected synergies; and
general economic conditions.
Any dilution of, or decrease or delay of any accretion to, our earnings per share could cause the price of our common shares to decline.
We will incur significant transaction and Merger-related costs in connection with the Merger, which may be in excess of those anticipated by us.
We expect to continue to incur a number of non-recurring costs associated with completing the Merger, combining the operations of the two companies and achieving anticipated synergies. These fees and costs have been, and will continue to be, substantial. The substantial majority of non-recurring expenses will consist of transaction costs related to the Merger and include, among others, fees paid to financial, legal and accounting advisors, employee retention costs, severance, change of control and benefit costs, and filing fees.
We will also incur transaction fees and costs related to formulating and implementing integration plans, including facilities and systems consolidation costs and employment-related costs. We will continue to assess the magnitude of these costs, and additional unanticipated costs may be incurred in the Merger and the integration of the two companies’ businesses. Although we expect that the elimination of duplicative costs, as well as the realization of other efficiencies related to the integration of the businesses, should allow us to offset integration-related costs over time, this net benefit may not be achieved in the near term or at all.
The costs described above, as well as other unanticipated costs and expenses, could have a material adverse effect on our financial condition and operating results following the completion of the Merger.
Many of these costs will be borne by us even if the Merger is not completed.
Following completion of the proposed Merger, our debt may limit our financial flexibility.
As of December 31, 2019, we had approximately $2.1 billion of outstanding indebtedness. We expect to incur and/or assume approximately $2.2 billion of debt to complete the acquisition of AK Steel. If we seek to refinance our and/or AK Steel’s existing indebtedness, there can be no guarantee that we would be able to execute the refinancing on favorable terms or at all. In addition, in connection with entering into the Merger Agreement, we obtained commitments to provide debt financing in an amount sufficient to repay AK Steel’s outstanding indebtedness under its revolving credit facility as well as AK Steel’s outstanding senior secured notes. Although the receipt of such financing is not a condition to the closing of the Merger, the unavailability of such financing could adversely impact the financial condition and liquidity of the combined company.
Assuming we do not repay, repurchase, redeem, exchange or otherwise terminate any of our or AK Steel’s existing indebtedness, immediately following the completion of the Merger, we expect to have approximately $4.3 billion of outstanding indebtedness.
Any increase in our indebtedness could have adverse effects on our financial condition and results of operations, including:
increasing our vulnerability to changing economic, regulatory and industry conditions;
limiting our ability to compete and our flexibil