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DISCONTINUED OPERATIONS (Details) (USD $)
In Millions, unless otherwise specified |
3 Months Ended | 12 Months Ended | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
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Dec. 31, 2014
|
Sep. 30, 2014
|
Dec. 31, 2013
|
Sep. 30, 2013
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Jun. 30, 2013
|
Mar. 31, 2013
|
Dec. 31, 2014
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Dec. 31, 2013
|
Dec. 31, 2012
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Jul. 10, 2012
|
|
| Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued ÈÕº«Èý¼¶Æ¬ [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Sale Price of CLCC Assets | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | $ 174.0clf_SalePriceofCLCCAssets | Ìý | Ìý | Ìý |
| Proceeds from sale of Cliffs Logan County Coal | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | 155.0clf_ProceedsfromsaleofCliffsLoganCountyCoal | 0clf_ProceedsfromsaleofCliffsLoganCountyCoal | 0clf_ProceedsfromsaleofCliffsLoganCountyCoal | Ìý |
| Statements of Consolidated ÈÕº«Èý¼¶Æ¬ | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| INCOME and GAIN ON SALE FROM DISCONTINUED OPERATIONS, net of tax | 0us-gaap_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬NetOfTax | 0us-gaap_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬NetOfTax | 0us-gaap_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬NetOfTax | 2.0us-gaap_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬NetOfTax | 0us-gaap_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬NetOfTax | 0us-gaap_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬NetOfTax | 0us-gaap_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬NetOfTax | 2.0us-gaap_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬NetOfTax | 35.9us-gaap_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬NetOfTax | Ìý |
| Sonoma [Member] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Statements of Consolidated ÈÕº«Èý¼¶Æ¬ | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Disposal Group, Including Discontinued Operation, Revenue | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
0us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedÈÕº«Èý¼¶Æ¬Axis = clf_SonomaMember |
0us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedÈÕº«Èý¼¶Æ¬Axis = clf_SonomaMember |
151.6us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedÈÕº«Èý¼¶Æ¬Axis = clf_SonomaMember |
Ìý |
| INCOME and GAIN ON SALE FROM DISCONTINUED OPERATIONS, net of tax |
0us-gaap_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬NetOfTax / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedÈÕº«Èý¼¶Æ¬Axis = clf_SonomaMember |
Ìý | Ìý | Ìý | Ìý | Ìý |
0us-gaap_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬NetOfTax / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedÈÕº«Èý¼¶Æ¬Axis = clf_SonomaMember |
2.0us-gaap_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬NetOfTax / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedÈÕº«Èý¼¶Æ¬Axis = clf_SonomaMember |
35.9us-gaap_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬NetOfTax / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedÈÕº«Èý¼¶Æ¬Axis = clf_SonomaMember |
Ìý |
| Sonoma [Member] | Asia Pacific Coal [Member] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued ÈÕº«Èý¼¶Æ¬ [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Percentage Of Ownership Interests | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
45.00%clf_PercentageOfOwnershipInterests / clf_InvesteeNameAxis = clf_SonomaMember / us-gaap_StatementBusinessSegmentsAxis = clf_AsiaPacificCoalMember |
| Income (Loss) From Discontinued ÈÕº«Èý¼¶Æ¬ [Member] | Sonoma [Member] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Statements of Consolidated ÈÕº«Èý¼¶Æ¬ | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
0us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedÈÕº«Èý¼¶Æ¬Axis = clf_SonomaMember / us-gaap_IncomeStatementLocationAxis = clf_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬Member |
0us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedÈÕº«Èý¼¶Æ¬Axis = clf_SonomaMember / us-gaap_IncomeStatementLocationAxis = clf_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬Member |
38.0us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedÈÕº«Èý¼¶Æ¬Axis = clf_SonomaMember / us-gaap_IncomeStatementLocationAxis = clf_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬Member |
Ìý |
| Discontinued Operation, Tax (Expense) Benefit from Provision for (Gain) Loss on Disposal | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
8.1us-gaap_DiscontinuedOperationTaxExpenseBenefitFromProvisionForGainLossOnDisposal / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedÈÕº«Èý¼¶Æ¬Axis = clf_SonomaMember / us-gaap_IncomeStatementLocationAxis = clf_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬Member |
Ìý |
| INCOME and GAIN ON SALE FROM DISCONTINUED OPERATIONS, net of tax | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
(2.1)us-gaap_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬NetOfTax / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedÈÕº«Èý¼¶Æ¬Axis = clf_SonomaMember / us-gaap_IncomeStatementLocationAxis = clf_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬Member |
Ìý |
| Discontinued Operation, Tax Effect of Discontinued Operation | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
$ 2.4us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedÈÕº«Èý¼¶Æ¬Axis = clf_SonomaMember / us-gaap_IncomeStatementLocationAxis = clf_IncomeLossFromDiscontinuedÈÕº«Èý¼¶Æ¬Member |
Ìý |
| Wabush [Member] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Statements of Consolidated ÈÕº«Èý¼¶Æ¬ | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Percentage of Consolidated Revenues | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
8.00%clf_PercentageofConsolidatedRevenues / clf_ReportingUnitAxis = clf_WabushMember |
Ìý | Ìý | Ìý |
| Percentage of Consolidated Assets | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
4.00%clf_PercentageofConsolidatedAssets / clf_ReportingUnitAxis = clf_WabushMember |
Ìý | Ìý | Ìý |
| CLCC [Member] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Statements of Consolidated ÈÕº«Èý¼¶Æ¬ | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Percentage of Consolidated Revenues | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
5.00%clf_PercentageofConsolidatedRevenues / clf_ReportingUnitAxis = clf_ClccMember |
Ìý | Ìý | Ìý |
| Percentage of Consolidated Assets | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
8.00%clf_PercentageofConsolidatedAssets / clf_ReportingUnitAxis = clf_ClccMember |
Ìý | Ìý | Ìý |
| Coal Revenue [Member] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Statements of Consolidated ÈÕº«Èý¼¶Æ¬ | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Percentage of Consolidated Revenues | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
15.00%clf_PercentageofConsolidatedRevenues / clf_RevenueTypeAxis = clf_CoalRevenueMember |
Ìý | Ìý | Ìý |
| X | ||||||||||
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- Definition
Percentage of Consolidated Assets No definition available.
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- Definition
Percentage of Consolidated Revenues No definition available.
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- Definition
The percentage of ownership of common stock or equity participation in the investee. No definition available.
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Proceeds from sale of Cliffs Logan County Coal No definition available.
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- Definition
Sale Price of CLCC Assets No definition available.
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| X | ||||||||||
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- Definition
Amount of gain (loss), after tax expense or benefit and not previously recognized, resulting from the sale of a business component. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Tax effect allocated to a disposal group that is classified as a component of the entity reported as a separate component of income before extraordinary items. Includes the tax effects of the following: income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Tax benefit from provision recognizing a loss for initial, or subsequent, write-down to fair value (less cost to sell) of a of a disposal group that is classified as a component of the entity, which remains unsold as of the reporting date. May include a tax on the (gain) for the recognition of a subsequent increase in fair value (less cost to sell), but not in excess of the cumulative loss previously recognized through write-downs. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount of sales or other form of revenues attributable to the disposal group, including a component of the entity (discontinued operation), during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Amount of income (loss) from a disposal group, net of income tax before extraordinary items allocable to noncontrolling interests. Includes, net of tax, income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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