Cleveland-Cliffs Inc. Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

Cover
- Document and Entity Information
Financial Statements
Notes to Financial Statements
Accounting Policies
- BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Policies)
Notes Tables
Notes Details

DERIVATIVE INSTRUMENTS - Schedule of Notional Amounts of Outstanding Derivatives (Details)

v3.20.2

DERIVATIVE INSTRUMENTS - Schedule of Notional Amounts of Outstanding Derivatives (Details) - Designated as Hedging Instrument [Member] lb in Millions, gal in Millions, MWh in Millions, MMBTU in Millions, $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2020 CAD ($) lb gal MMBTU MWh	Dec. 31, 2019 CAD ($) MMBTU lb gal MWh
Natural Gas [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount \| MMBTU	29.7	20.1
Diesel [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount \| gal	0.0	0.8
Zinc [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount \| lb	10.9	0.0
Electricity [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure \| MWh	0.8	0.0
Canada, Dollars \| Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount \| $	$ 38.8	$ 0.0

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Nominal number of units used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Nominal energy measure used to calculate payments on a derivative instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeNonmonetaryNotionalAmountEnergyMeasure
Namespace Prefix:	us-gaap_
Data Type:	num:energyItemType
Balance Type:	na
Period Type:	duration

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Details

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Namespace Prefix:
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- Details

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- Details

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- Details

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Namespace Prefix:
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- Details

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Namespace Prefix:
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- Details

Name:	srt_CurrencyAxis=currency_CAD
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- Details

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