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GOODWILL AND OTHER INTANGIBLE ASSETS AND LIABILITIES (Schedule Of Goodwill) (Details) (USD $)
In Millions, unless otherwise specified |
12 Months Ended | |
|---|---|---|
|
Dec. 31, 2014
|
Dec. 31, 2013
|
|
| Goodwill [Roll Forward] | ||
| Beginning Balance | $ 74.5us-gaap_Goodwill | $ 167.4us-gaap_Goodwill |
| Arising in business combinations | 0us-gaap_GoodwillAcquiredDuringPeriod | 0us-gaap_GoodwillAcquiredDuringPeriod |
| Impairment | (73.5)us-gaap_GoodwillImpairmentLoss | (80.9)us-gaap_GoodwillImpairmentLoss |
| Impact of foreign currency translation | 1.0us-gaap_GoodwillTranslationAndPurchaseAccountingAdjustments | (12.0)us-gaap_GoodwillTranslationAndPurchaseAccountingAdjustments |
| Ending Balance | 2.0us-gaap_Goodwill | 74.5us-gaap_Goodwill |
| Accumulated Goodwill Impairment Loss | (1,154.4)us-gaap_GoodwillImpairedAccumulatedImpairmentLoss | (1,080.9)us-gaap_GoodwillImpairedAccumulatedImpairmentLoss |
| U.S. Iron Ore [Member] | ||
| Goodwill [Roll Forward] | ||
| Beginning Balance |
2.0us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = clf_USIronOreMember |
2.0us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = clf_USIronOreMember |
| Arising in business combinations |
0us-gaap_GoodwillAcquiredDuringPeriod / us-gaap_StatementBusinessSegmentsAxis = clf_USIronOreMember |
0us-gaap_GoodwillAcquiredDuringPeriod / us-gaap_StatementBusinessSegmentsAxis = clf_USIronOreMember |
| Impairment |
0us-gaap_GoodwillImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = clf_USIronOreMember |
0us-gaap_GoodwillImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = clf_USIronOreMember |
| Impact of foreign currency translation |
0us-gaap_GoodwillTranslationAndPurchaseAccountingAdjustments / us-gaap_StatementBusinessSegmentsAxis = clf_USIronOreMember |
0us-gaap_GoodwillTranslationAndPurchaseAccountingAdjustments / us-gaap_StatementBusinessSegmentsAxis = clf_USIronOreMember |
| Ending Balance |
2.0us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = clf_USIronOreMember |
2.0us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = clf_USIronOreMember |
| Accumulated Goodwill Impairment Loss |
0us-gaap_GoodwillImpairedAccumulatedImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = clf_USIronOreMember |
0us-gaap_GoodwillImpairedAccumulatedImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = clf_USIronOreMember |
| Eastern Canadian Iron Ore [Member] | ||
| Goodwill [Roll Forward] | ||
| Beginning Balance |
0us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = clf_EasternCanadianIronOreMember |
0us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = clf_EasternCanadianIronOreMember |
| Arising in business combinations |
0us-gaap_GoodwillAcquiredDuringPeriod / us-gaap_StatementBusinessSegmentsAxis = clf_EasternCanadianIronOreMember |
0us-gaap_GoodwillAcquiredDuringPeriod / us-gaap_StatementBusinessSegmentsAxis = clf_EasternCanadianIronOreMember |
| Impairment |
0us-gaap_GoodwillImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = clf_EasternCanadianIronOreMember |
0us-gaap_GoodwillImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = clf_EasternCanadianIronOreMember |
| Impact of foreign currency translation |
0us-gaap_GoodwillTranslationAndPurchaseAccountingAdjustments / us-gaap_StatementBusinessSegmentsAxis = clf_EasternCanadianIronOreMember |
0us-gaap_GoodwillTranslationAndPurchaseAccountingAdjustments / us-gaap_StatementBusinessSegmentsAxis = clf_EasternCanadianIronOreMember |
| Ending Balance |
0us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = clf_EasternCanadianIronOreMember |
0us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = clf_EasternCanadianIronOreMember |
| Accumulated Goodwill Impairment Loss |
(1,000.0)us-gaap_GoodwillImpairedAccumulatedImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = clf_EasternCanadianIronOreMember |
(1,000.0)us-gaap_GoodwillImpairedAccumulatedImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = clf_EasternCanadianIronOreMember |
| Asia Pacific Iron Ore [Member] | ||
| Goodwill [Roll Forward] | ||
| Beginning Balance |
72.5us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = clf_AsiaPacificIronOreMember |
84.5us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = clf_AsiaPacificIronOreMember |
| Arising in business combinations |
0us-gaap_GoodwillAcquiredDuringPeriod / us-gaap_StatementBusinessSegmentsAxis = clf_AsiaPacificIronOreMember |
0us-gaap_GoodwillAcquiredDuringPeriod / us-gaap_StatementBusinessSegmentsAxis = clf_AsiaPacificIronOreMember |
| Impairment |
(73.5)us-gaap_GoodwillImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = clf_AsiaPacificIronOreMember |
0us-gaap_GoodwillImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = clf_AsiaPacificIronOreMember |
| Impact of foreign currency translation |
1.0us-gaap_GoodwillTranslationAndPurchaseAccountingAdjustments / us-gaap_StatementBusinessSegmentsAxis = clf_AsiaPacificIronOreMember |
(12.0)us-gaap_GoodwillTranslationAndPurchaseAccountingAdjustments / us-gaap_StatementBusinessSegmentsAxis = clf_AsiaPacificIronOreMember |
| Ending Balance |
0us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = clf_AsiaPacificIronOreMember |
72.5us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = clf_AsiaPacificIronOreMember |
| Accumulated Goodwill Impairment Loss |
(73.5)us-gaap_GoodwillImpairedAccumulatedImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = clf_AsiaPacificIronOreMember |
0us-gaap_GoodwillImpairedAccumulatedImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = clf_AsiaPacificIronOreMember |
| Other Segment [Member] | ||
| Goodwill [Roll Forward] | ||
| Beginning Balance |
0us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = clf_OtherSegmentMember |
80.9us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = clf_OtherSegmentMember |
| Arising in business combinations |
0us-gaap_GoodwillAcquiredDuringPeriod / us-gaap_StatementBusinessSegmentsAxis = clf_OtherSegmentMember |
0us-gaap_GoodwillAcquiredDuringPeriod / us-gaap_StatementBusinessSegmentsAxis = clf_OtherSegmentMember |
| Impairment |
80.9us-gaap_GoodwillImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = clf_OtherSegmentMember |
|
| Impact of foreign currency translation |
0us-gaap_GoodwillTranslationAndPurchaseAccountingAdjustments / us-gaap_StatementBusinessSegmentsAxis = clf_OtherSegmentMember |
0us-gaap_GoodwillTranslationAndPurchaseAccountingAdjustments / us-gaap_StatementBusinessSegmentsAxis = clf_OtherSegmentMember |
| Ending Balance |
0us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = clf_OtherSegmentMember |
0us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = clf_OtherSegmentMember |
| Accumulated Goodwill Impairment Loss |
(80.9)us-gaap_GoodwillImpairedAccumulatedImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = clf_OtherSegmentMember |
(80.9)us-gaap_GoodwillImpairedAccumulatedImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = clf_OtherSegmentMember |
| Other Segment [Member] | ||
| Goodwill [Roll Forward] | ||
| Impairment |
$ 0us-gaap_GoodwillImpairmentLoss / clf_ReportingUnitAxis = clf_OtherSegmentMember |
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| X | ||||||||||
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- Definition
Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount of increase (decrease) from foreign currency translation adjustments and purchase accounting adjustments of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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