Annual report pursuant to Section 13 and 15(d)

SEGMENT REPORTING (Schedule Of Segment Reporting Information, By Segment) (Details)

v2.4.1.9
SEGMENT REPORTING (Schedule Of Segment Reporting Information, By Segment) (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended 12 Months Ended
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2013
Sep. 30, 2013
Jun. 30, 2013
Mar. 31, 2013
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Segment Reporting Information [Line Items]                      
Net income (loss)                 $ (8,311.6)us-gaap_ProfitLoss $ 361.8us-gaap_ProfitLoss $ (1,126.6)us-gaap_ProfitLoss
Revenues from product sales and services 1,284.7us-gaap_Revenues 1,298.2us-gaap_Revenues 1,100.8us-gaap_Revenues 940.0us-gaap_Revenues 1,515.8us-gaap_Revenues 1,546.6us-gaap_Revenues 1,488.5us-gaap_Revenues 1,140.5us-gaap_Revenues 4,623.7us-gaap_Revenues 5,691.4us-gaap_Revenues 5,872.7us-gaap_Revenues
Revenues from producet sales and services, percent                 100.00%clf_PercentageOfSegmentRevenue 100.00%clf_PercentageOfSegmentRevenue 100.00%clf_PercentageOfSegmentRevenue
SALES MARGIN 168.7us-gaap_GrossProfit 127.5us-gaap_GrossProfit 92.0us-gaap_GrossProfit 63.2us-gaap_GrossProfit 294.5us-gaap_GrossProfit 348.7us-gaap_GrossProfit 268.2us-gaap_GrossProfit 237.9us-gaap_GrossProfit 451.4us-gaap_GrossProfit 1,149.3us-gaap_GrossProfit 1,172.1us-gaap_GrossProfit
Other operating expense                 (9,896.7)us-gaap_OperatingExpenses (478.3)us-gaap_OperatingExpenses (1,480.9)us-gaap_OperatingExpenses
Other expense                 (158.4)us-gaap_NonoperatingIncomeExpense (181.7)us-gaap_NonoperatingIncomeExpense (193.0)us-gaap_NonoperatingIncomeExpense
Income (loss) from continuing operations before income taxes and equity income (loss) from ventures                 (9,603.7)us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments 489.3us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments (501.8)us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
Depreciation, depletion and amortization                 504.0us-gaap_DepreciationDepletionAndAmortization 593.3us-gaap_DepreciationDepletionAndAmortization 525.8us-gaap_DepreciationDepletionAndAmortization
Capital Additions                 235.5us-gaap_PropertyPlantAndEquipmentAdditions 752.3us-gaap_PropertyPlantAndEquipmentAdditions 1,335.3us-gaap_PropertyPlantAndEquipmentAdditions
Interest expense, net                 (185.2)us-gaap_InterestIncomeExpenseNet (179.1)us-gaap_InterestIncomeExpenseNet (195.6)us-gaap_InterestIncomeExpenseNet
Income Tax Expense (Benefit) (289.7)us-gaap_IncomeTaxExpenseBenefit               (1,302.0)us-gaap_IncomeTaxExpenseBenefit 55.1us-gaap_IncomeTaxExpenseBenefit 255.9us-gaap_IncomeTaxExpenseBenefit
EBITDA                 (8,924.4)clf_EBITDA 1,189.3clf_EBITDA (149.3)clf_EBITDA
Equity Method Investment, Other than Temporary Impairment                 0us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment 0us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment (365.4)us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment
Loss on sale of Cliffs Logan County Coal                 419.6clf_LossonsaleofCliffsLoganCountyCoal 0clf_LossonsaleofCliffsLoganCountyCoal 0clf_LossonsaleofCliffsLoganCountyCoal
Adjusted EBITDA                 929.7clf_AdjustedEBITDA 1,428.3clf_AdjustedEBITDA 1,292.9clf_AdjustedEBITDA
U.S. Iron Ore [Member]                      
Segment Reporting Information [Line Items]                      
Revenues from product sales and services                 2,506.5us-gaap_Revenues
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember 		2,667.9us-gaap_Revenues
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember 		2,723.3us-gaap_Revenues
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember
Revenues from producet sales and services, percent                 54.00%clf_PercentageOfSegmentRevenue
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember 		47.00%clf_PercentageOfSegmentRevenue
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember 		46.00%clf_PercentageOfSegmentRevenue
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember
SALES MARGIN                 710.4us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember 		901.9us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember 		976.2us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember
Depreciation, depletion and amortization                 107.4us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember 		120.3us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember 		100.9us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember
Capital Additions                 48.4us-gaap_PropertyPlantAndEquipmentAdditions
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember 		[1] 53.3us-gaap_PropertyPlantAndEquipmentAdditions
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember 		[1] 168.8us-gaap_PropertyPlantAndEquipmentAdditions
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember 		[1]
EBITDA                 805.6clf_EBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember 		1,000.1clf_EBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember 		1,045.3clf_EBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember
Adjusted EBITDA                 831.2clf_AdjustedEBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember 		1,030.8clf_AdjustedEBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember 		1,085.6clf_AdjustedEBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreMember
Eastern Canadian Iron Ore [Member]                      
Segment Reporting Information [Line Items]                      
Revenues from product sales and services                 563.4us-gaap_Revenues
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember 		978.7us-gaap_Revenues
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember 		1,008.9us-gaap_Revenues
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember
Revenues from producet sales and services, percent                 12.00%clf_PercentageOfSegmentRevenue
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember 		17.00%clf_PercentageOfSegmentRevenue
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember 		17.00%clf_PercentageOfSegmentRevenue
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember
SALES MARGIN                 (244.9)us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember 		(103.3)us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember 		(121.4)us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember
Depreciation, depletion and amortization                 135.6us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember 		178.5us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember 		160.2us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember
Capital Additions                 141.2us-gaap_PropertyPlantAndEquipmentAdditions
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember 		[1] 625.5us-gaap_PropertyPlantAndEquipmentAdditions
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember 		[1] 865.2us-gaap_PropertyPlantAndEquipmentAdditions
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember 		[1]
EBITDA                 (7,673.9)clf_EBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember 		(192.8)clf_EBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember 		(1,103.3)clf_EBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember
Adjusted EBITDA                 0clf_AdjustedEBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember 		0clf_AdjustedEBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember 		0clf_AdjustedEBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_EasternCanadianIronOreMember
Asia Pacific Iron Ore [Member]                      
Segment Reporting Information [Line Items]                      
Revenues from product sales and services                 866.7us-gaap_Revenues
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember 		1,224.3us-gaap_Revenues
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember 		1,259.3us-gaap_Revenues
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember
Revenues from producet sales and services, percent                 19.00%clf_PercentageOfSegmentRevenue
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember 		22.00%clf_PercentageOfSegmentRevenue
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember 		22.00%clf_PercentageOfSegmentRevenue
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember
SALES MARGIN                 121.7us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember 		367.1us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember 		311.0us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember
Depreciation, depletion and amortization                 145.9us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember 		153.7us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember 		151.9us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember
Capital Additions                 10.8us-gaap_PropertyPlantAndEquipmentAdditions
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember 		[1] 13.0us-gaap_PropertyPlantAndEquipmentAdditions
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember 		[1] 87.7us-gaap_PropertyPlantAndEquipmentAdditions
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember 		[1]
EBITDA                 (369.8)clf_EBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember 		500.4clf_EBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember 		387.3clf_EBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember
Adjusted EBITDA                 264.6clf_AdjustedEBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember 		525.7clf_AdjustedEBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember 		402.1clf_AdjustedEBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_AsiaPacificIronOreMember
North American Coal [Member]                      
Segment Reporting Information [Line Items]                      
Revenues from product sales and services                 687.1us-gaap_Revenues
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember 		821.9us-gaap_Revenues
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember 		881.1us-gaap_Revenues
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember
Revenues from producet sales and services, percent                 15.00%clf_PercentageOfSegmentRevenue
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember 		14.00%clf_PercentageOfSegmentRevenue
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember 		15.00%clf_PercentageOfSegmentRevenue
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember
SALES MARGIN                 (135.8)us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember 		(14.5)us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember 		(1.8)us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember
Depreciation, depletion and amortization                 106.9us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember 		128.9us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember 		98.2us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember
Capital Additions                 28.8us-gaap_PropertyPlantAndEquipmentAdditions
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember 		[1] 55.0us-gaap_PropertyPlantAndEquipmentAdditions
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember 		[1] 144.1us-gaap_PropertyPlantAndEquipmentAdditions
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember 		[1]
EBITDA                 (1,326.8)clf_EBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember 		129.5clf_EBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember 		74.0clf_EBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember
Adjusted EBITDA                 (28.5)clf_AdjustedEBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember 		154.0clf_AdjustedEBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember 		106.7clf_AdjustedEBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_NorthAmericanCoalMember
All Other Segments [Member]                      
Segment Reporting Information [Line Items]                      
Revenues from product sales and services                 0us-gaap_Revenues
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember 		(1.4)us-gaap_Revenues
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember 		0.1us-gaap_Revenues
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember
Revenues from producet sales and services, percent                 0.00%clf_PercentageOfSegmentRevenue
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember 		0.00%clf_PercentageOfSegmentRevenue
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember 		0.00%clf_PercentageOfSegmentRevenue
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember
SALES MARGIN                 0us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember 		(1.9)us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember 		8.1us-gaap_GrossProfit
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember
Depreciation, depletion and amortization                 8.2us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember 		11.9us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember 		14.6us-gaap_DepreciationDepletionAndAmortization
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember
Capital Additions                 6.3us-gaap_PropertyPlantAndEquipmentAdditions
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember 		[1] 5.5us-gaap_PropertyPlantAndEquipmentAdditions
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember 		[1] 69.5us-gaap_PropertyPlantAndEquipmentAdditions
/ us-gaap_StatementBusinessSegmentsAxis
= us-gaap_AllOtherSegmentsMember 		[1]
Other Segment [Member]                      
Segment Reporting Information [Line Items]                      
EBITDA                 (359.5)clf_EBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_OtherSegmentMember 		(247.9)clf_EBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_OtherSegmentMember 		(552.6)clf_EBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_OtherSegmentMember
Adjusted EBITDA                 (137.6)clf_AdjustedEBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_OtherSegmentMember 		(282.2)clf_AdjustedEBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_OtherSegmentMember 		(301.5)clf_AdjustedEBITDA
/ us-gaap_StatementBusinessSegmentsAxis
= clf_OtherSegmentMember
EBITDA Calculation [Member]                      
Segment Reporting Information [Line Items]                      
Depreciation, depletion and amortization                 (504.0)us-gaap_DepreciationDepletionAndAmortization
/ clf_EBITDACalculationAxis
= clf_EBITDACalculationMember 		(593.3)us-gaap_DepreciationDepletionAndAmortization
/ clf_EBITDACalculationAxis
= clf_EBITDACalculationMember 		(525.8)us-gaap_DepreciationDepletionAndAmortization
/ clf_EBITDACalculationAxis
= clf_EBITDACalculationMember
Amapa [Member]                      
Segment Reporting Information [Line Items]                      
Equity Method Investment, Other than Temporary Impairment                   67.6us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= clf_AmapaMember 		(365.4)us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= clf_AmapaMember
Adjusted EBITDA Calculation [Member]                      
Segment Reporting Information [Line Items]                      
Loss on sale of Cliffs Logan County Coal                 (419.6)clf_LossonsaleofCliffsLoganCountyCoal
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember 		0clf_LossonsaleofCliffsLoganCountyCoal
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember 		0clf_LossonsaleofCliffsLoganCountyCoal
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember
Wabush mine related costs                 (158.7)clf_Wabushminerelatedcosts
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember 		(72.7)clf_Wabushminerelatedcosts
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember 		(30.1)clf_Wabushminerelatedcosts
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember
Bloom Lake mine costs                 (137.9)clf_BloomLakeminecosts
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember 		46.5clf_BloomLakeminecosts
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember 		6.4clf_BloomLakeminecosts
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember
Foreign Exchange Remeasurement                 30.7clf_ForeignExchangeRemeasurement
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember 		64.0clf_ForeignExchangeRemeasurement
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember 		(3.2)clf_ForeignExchangeRemeasurement
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember
Proxy contest and change in control costs in SG&A                 (26.6)clf_ProxycontestandchangeincontrolcostsinSGA
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember 		0clf_ProxycontestandchangeincontrolcostsinSGA
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember 		0clf_ProxycontestandchangeincontrolcostsinSGA
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember
Litigation Judgment Costs                 (96.3)clf_LitigationJudgmentCosts
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember 		(9.6)clf_LitigationJudgmentCosts
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember 		0clf_LitigationJudgmentCosts
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember
Severance Costs in SG&A                 $ (15.8)clf_SeveranceCostsinSGA
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember 		$ (16.4)clf_SeveranceCostsinSGA
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember 		$ 0clf_SeveranceCostsinSGA
/ clf_AdjustedEBITACalculationAxis
= clf_AdjustedEBITDACalculationMember
[1] 1 Includes capital lease additions and non-cash accruals. Refer to NOTE 17 - CASH FLOW INFORMATION.