根据第13和15(d)条提交的年度报告

债务及信贷安排（长期债务一览表）（详情）

v2.4.1.9
债务及信贷安排（长期债务一览表）（详情）（美元）
3个月结束 12个月结束
2014年12月31日
2014年12月31日
2013年12月31日
2014年9月30日
债务文书〔细目〕        
债务契约净值计算中允许排除的最大减值 1000000000美元clf_MaximumImpairmentPermittedtobeExcludedfromNetWorthCalculationforDebtCovenants 1000000000美元clf_MaximumImpairmentPermittedtobeExcludedfromNetWorthCalculationforDebtCovenants    
股票回购计划，授权金额 200000000年us-gaap_StockRepurchaseProgramAuthorizedAmount1 200000000年us-gaap_StockRepurchaseProgramAuthorizedAmount1    
债务工具，票面价值 4144800000年clf_DebtInstrumentParValue 4144800000年clf_DebtInstrumentParValue 4814800000年clf_DebtInstrumentParValue  
长期债务 2984100000年us-gaap_LongTermDebt 2984100000年us-gaap_LongTermDebt 3043500000年us-gaap_LongTermDebt  
长期债务的流动部分 21800000年us-gaap_LongTermDebtCurrent 21800000年us-gaap_LongTermDebtCurrent 20900000年us-gaap_LongTermDebtCurrent  
长期债务非流动部分 2962300000年us-gaap_LongTermDebtNoncurrent 2962300000年us-gaap_LongTermDebtNoncurrent 3022600000年us-gaap_LongTermDebtNoncurrent  
七亿肆点八十七五二千二十一优先票据[成员]        
债务文书〔细目〕        
债务工具，回购票面金额 10000000年us-gaap_DebtInstrumentRepurchasedFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		10000000年us-gaap_DebtInstrumentRepurchasedFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		   
规定利率 4.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		4.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		   
债务工具，票面价值 690000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		690000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		700000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		 
债务工具，未摊销贴现 500000年us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		500000年us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		600000年us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		 
债务回购贴现 40.50%clf_DebtRepurchaseDiscount
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		40.50%clf_DebtRepurchaseDiscount
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		   
债务清偿的收益（损失）   4100000年us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		   
类型   固定 固定  
最后的期限   2021 2021  
长期债务 689500000年us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		［1］ 689500000年us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		［1］ 699400000年us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		［1］  
估算利率 4.88%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		4.88%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		4.88%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		 
债务工具，票面金额 700000000年us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		700000000年us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		700000000年us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_SevenHundredMillionFourPointEightSevenFiveTwoThousandTwentyoneSeniorNoteMember 		 
$5亿4.80% 2020优先票据[成员]        
债务文书〔细目〕        
债务工具，回购票面金额 10000000年us-gaap_DebtInstrumentRepurchasedFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		10000000年us-gaap_DebtInstrumentRepurchasedFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		   
规定利率 4.80%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		4.80%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		4.80%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		 
债务工具，票面价值 490000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		490000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		500000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		 
债务工具，未摊销贴现 600000年us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		600000年us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		800000年us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		 
债务回购贴现 40.25%clf_DebtRepurchaseDiscount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		40.25%clf_DebtRepurchaseDiscount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		   
债务清偿的收益（损失）   4000000年us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		   
类型   固定 固定  
最后的期限   2020 2020  
长期债务 489400000年us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		[2] 489400000年us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		[2] 499200000年us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		[2]  
估算利率 4.83%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		4.83%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		4.83%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		 
债务工具，票面金额 500000000 .0us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		500000000 .0us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		500000000年us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		 
用于计算待赎回票据本金和利息的剩余计划支付现值的贴现率，可变利率基础   国债收益率    
用于计算待赎回票据本金和利息的剩余计划支付现值的贴现率，按利率计算 0.35%clf_DiscountRateUsedToCalculatePresentValuesOfRemainingScheduledPaymentsOfPrincipalAndInterestOnNotesToBeRedeemedSpreadOnRateBasis
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		0.35%clf_DiscountRateUsedToCalculatePresentValuesOfRemainingScheduledPaymentsOfPrincipalAndInterestOnNotesToBeRedeemedSpreadOnRateBasis
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionFourPointEightZeroPercentSeniorNoteMember 		   
$8亿6.25% 2040优先票据[成员]        
债务文书〔细目〕        
规定利率 6.25%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= clf_EightHundredMillionSixPointTwoFivePercentSeniorNotesDueTwoThousandFortyMember 		6.25%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= clf_EightHundredMillionSixPointTwoFivePercentSeniorNotesDueTwoThousandFortyMember 		6.25%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= clf_EightHundredMillionSixPointTwoFivePercentSeniorNotesDueTwoThousandFortyMember 		 
债务工具，票面价值 800000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= clf_EightHundredMillionSixPointTwoFivePercentSeniorNotesDueTwoThousandFortyMember 		800000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= clf_EightHundredMillionSixPointTwoFivePercentSeniorNotesDueTwoThousandFortyMember 		800000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= clf_EightHundredMillionSixPointTwoFivePercentSeniorNotesDueTwoThousandFortyMember 		 
债务工具，未摊销贴现 9500000年us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= clf_EightHundredMillionSixPointTwoFivePercentSeniorNotesDueTwoThousandFortyMember 		9500000年us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= clf_EightHundredMillionSixPointTwoFivePercentSeniorNotesDueTwoThousandFortyMember 		9600000年us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= clf_EightHundredMillionSixPointTwoFivePercentSeniorNotesDueTwoThousandFortyMember 		 
类型   固定 固定  
最后的期限   2040 2040  
长期债务 790500000年us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= clf_EightHundredMillionSixPointTwoFivePercentSeniorNotesDueTwoThousandFortyMember 		[3] 790500000年us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= clf_EightHundredMillionSixPointTwoFivePercentSeniorNotesDueTwoThousandFortyMember 		[3] 790400000年us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= clf_EightHundredMillionSixPointTwoFivePercentSeniorNotesDueTwoThousandFortyMember 		[3]  
估算利率 6.34%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= clf_EightHundredMillionSixPointTwoFivePercentSeniorNotesDueTwoThousandFortyMember 		6.34%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= clf_EightHundredMillionSixPointTwoFivePercentSeniorNotesDueTwoThousandFortyMember 		6.34%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= clf_EightHundredMillionSixPointTwoFivePercentSeniorNotesDueTwoThousandFortyMember 		 
债务工具，票面金额 800000000年us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_EightHundredMillionSixPointTwoFivePercentSeniorNotesDueTwoThousandFortyMember 		800000000年us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_EightHundredMillionSixPointTwoFivePercentSeniorNotesDueTwoThousandFortyMember 		   
$4亿5.90% 2020优先票据[成员]        
债务文书〔细目〕        
债务工具，回购票面金额 5000000年us-gaap_DebtInstrumentRepurchasedFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		5000000年us-gaap_DebtInstrumentRepurchasedFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		   
规定利率 5.90%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		5.90%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		5.90%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		 
债务工具，票面价值 395000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		395000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		400000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		 
债务工具，未摊销贴现 1300000年us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		1300000年us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		1600000年us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		 
债务回购贴现 38.125%clf_DebtRepurchaseDiscount
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		38.125%clf_DebtRepurchaseDiscount
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		   
债务清偿的收益（损失）   1900000 .0us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		   
类型   固定 固定  
最后的期限   2020 2020  
长期债务 393700000年us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		[4] 393700000年us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		[4] 398400000年us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		[4]  
估算利率 5.98%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		5.98%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		5.98%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		 
债务工具，票面金额 400000000年us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		400000000年us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		400000000年us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_FourHundredMillionFivePointNineZeroTwoThousandAndTwentySeniorNoteMember 		 
$5亿3.95% 2018优先票据[成员]        
债务文书〔细目〕        
债务工具，回购票面金额 20000000年us-gaap_DebtInstrumentRepurchasedFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		20000000年us-gaap_DebtInstrumentRepurchasedFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		   
规定利率 3.95%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		3.95%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		   
债务工具，票面价值 480000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		480000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		500000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		 
债务工具，未摊销贴现 2600000年us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		2600000年us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		3500000年us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		 
债务回购贴现 30.875%clf_DebtRepurchaseDiscount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		30.875%clf_DebtRepurchaseDiscount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		   
债务清偿的收益（损失）   6200000年us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		   
类型   固定 固定  
最后的期限   2018 2018  
长期债务 477400000年us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		[5] 477400000年us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		[5] 496500000年us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		[5]  
估算利率 5.17%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		5.17%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		4.14%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		 
债务工具，票面金额 500000000年us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		500000000年us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		500000000 .0us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionThreePointNineFiveTwoThousandEighteenSeniorNoteMember 		 
循环信贷安排〔成员〕        
债务文书〔细目〕        
利息、税项、折旧及摊销前收益对利息支出总额的覆盖比率 3.5clf_CoverageRatioOfEarningsBeforeInterestTaxDepreciationAndAmortizationToTotalInterestExpense
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember 		  ２.５clf_CoverageRatioOfEarningsBeforeInterestTaxDepreciationAndAmortizationToTotalInterestExpense
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember 		 
利息、税项、折旧及摊销前收益对后续事件利息支出总额的覆盖率-循环信贷安排修订 2.0clf_CoverageRatioOfEarningsBeforeInterestTaxDepreciationAndAmortizationToTotalInterestExpenseSubsequentEventRevolvingCreditFacilityAmendment
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember 		     
完成抵押行动以降低最低利息覆盖率的天数，后续事件-循环信贷额度修正案 60clf_NumberofDaystocompletecollateralactioninordertoreduceminimuminterestcoverageratioSubsequentEventRevolvingCreditFacilityAmendment
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember 		     
债务工具，票面价值 1125000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember 		1125000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember 		1750000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember 		1250000000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember
类型   变量 变量  
最后的期限   2017 2017  
信用额度，未偿金额 0us-gaap_LineOfCredit
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember 		[6] 0us-gaap_LineOfCredit
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember 		[6] 0us-gaap_LineOfCredit
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember 		[6]  
估算利率 2.94%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember 		2.94%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember 		1.64%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember 		 
信贷额度剩余能力 1000000000年us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember 		1000000000年us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember 		1700000000年us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember 		 
信用证〔成员〕        
债务文书〔细目〕        
信用额度，未偿金额 149500000年us-gaap_LineOfCredit
/ us-gaap_DebtInstrumentAxis
= us-gaap_LetterOfCreditMember 		149500000年us-gaap_LineOfCredit
/ us-gaap_DebtInstrumentAxis
= us-gaap_LetterOfCreditMember 		8400000年us-gaap_LineOfCredit
/ us-gaap_DebtInstrumentAxis
= us-gaap_LetterOfCreditMember 		 
设备贷款〔会员〕        
债务文书〔细目〕        
债务工具，票面价值 164800000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= clf_EquipmentLoansMember 		164800000年clf_DebtInstrumentParValue
/ us-gaap_DebtInstrumentAxis
= clf_EquipmentLoansMember 		   
类型   固定 固定  
长期债务 140800000年us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= clf_EquipmentLoansMember 		140800000年us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= clf_EquipmentLoansMember 		161700000年us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= clf_EquipmentLoansMember 		 
利率掉期〔成员〕        
债务文书〔细目〕        
利率套期保值的公允价值调整 2800000年clf_FairValueAdjustmenttoInterestRateHedge
/ us-gaap_DebtInstrumentAxis
= us-gaap_InterestRateSwapMember 		2800000年clf_FairValueAdjustmenttoInterestRateHedge
/ us-gaap_DebtInstrumentAxis
= us-gaap_InterestRateSwapMember 		(2100000)clf_FairValueAdjustmenttoInterestRateHedge
/ us-gaap_DebtInstrumentAxis
= us-gaap_InterestRateSwapMember 		 
优先票据五亿[成员]        
债务文书〔细目〕        
用于计算待赎回票据本金和利息的剩余计划支付现值的贴现率，可变利率基础   国债收益率    
用于计算待赎回票据本金和利息的剩余计划支付现值的贴现率，按利率计算 0.50%clf_DiscountRateUsedToCalculatePresentValuesOfRemainingScheduledPaymentsOfPrincipalAndInterestOnNotesToBeRedeemedSpreadOnRateBasis
/ us-gaap_DebtInstrumentAxis
= clf_SeniorNotesFiveHundredMillionMember 		0.50%clf_DiscountRateUsedToCalculatePresentValuesOfRemainingScheduledPaymentsOfPrincipalAndInterestOnNotesToBeRedeemedSpreadOnRateBasis
/ us-gaap_DebtInstrumentAxis
= clf_SeniorNotesFiveHundredMillionMember 		   
优先债券10年期部分〔成员〕        
债务文书〔细目〕        
用于计算待赎回票据本金和利息的剩余计划支付现值的贴现率，可变利率基础   国债收益率    
用于计算待赎回票据本金和利息的剩余计划支付现值的贴现率，按利率计算 0.25%clf_DiscountRateUsedToCalculatePresentValuesOfRemainingScheduledPaymentsOfPrincipalAndInterestOnNotesToBeRedeemedSpreadOnRateBasis
/ us-gaap_DebtInstrumentAxis
= clf_SeniorNotes10YearTrancheMember 		0.25%clf_DiscountRateUsedToCalculatePresentValuesOfRemainingScheduledPaymentsOfPrincipalAndInterestOnNotesToBeRedeemedSpreadOnRateBasis
/ us-gaap_DebtInstrumentAxis
= clf_SeniorNotes10YearTrancheMember 		   
优先债券30年期部分〔成员〕        
债务文书〔细目〕        
债务工具，票面金额 300000000年us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_ThreeHundredMillionSixPointTwoFivePercentTwoThousandAndFortyMember 		300000000年us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_ThreeHundredMillionSixPointTwoFivePercentTwoThousandAndFortyMember 		   
用于计算待赎回票据本金和利息的剩余计划支付现值的贴现率，可变利率基础   国债收益率    
用于计算待赎回票据本金和利息的剩余计划支付现值的贴现率，按利率计算 0.40%clf_DiscountRateUsedToCalculatePresentValuesOfRemainingScheduledPaymentsOfPrincipalAndInterestOnNotesToBeRedeemedSpreadOnRateBasis
/ us-gaap_DebtInstrumentAxis
= clf_ThreeHundredMillionSixPointTwoFivePercentTwoThousandAndFortyMember 		0.40%clf_DiscountRateUsedToCalculatePresentValuesOfRemainingScheduledPaymentsOfPrincipalAndInterestOnNotesToBeRedeemedSpreadOnRateBasis
/ us-gaap_DebtInstrumentAxis
= clf_ThreeHundredMillionSixPointTwoFivePercentTwoThousandAndFortyMember 		   
五亿六点二百分零点四[成员]        
债务文书〔细目〕        
债务工具，票面金额 500000000美元us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionSixPointTwoFivePercentTwoThousandAndFortyMember 		500000000美元us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionSixPointTwoFivePercentTwoThousandAndFortyMember 		   
用于计算待赎回票据本金和利息的剩余计划支付现值的贴现率，可变利率基础   国债收益率    
用于计算待赎回票据本金和利息的剩余计划支付现值的贴现率，按利率计算 0.40%clf_DiscountRateUsedToCalculatePresentValuesOfRemainingScheduledPaymentsOfPrincipalAndInterestOnNotesToBeRedeemedSpreadOnRateBasis
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionSixPointTwoFivePercentTwoThousandAndFortyMember 		0.40%clf_DiscountRateUsedToCalculatePresentValuesOfRemainingScheduledPaymentsOfPrincipalAndInterestOnNotesToBeRedeemedSpreadOnRateBasis
/ us-gaap_DebtInstrumentAxis
= clf_FiveHundredMillionSixPointTwoFivePercentTwoThousandAndFortyMember 		   
［1］ 在2014年第四季度，我们以40.5%的折扣购买了1000万美元未偿还的4.875%的优先票据，这导致了410万美元的债务清偿收益。截至2014年12月31日，根据4.88%的估算利率，价值7亿美元的4.875%优先票据的票面价值为6.9亿美元减去50万美元的未摊销折扣。截至2013年12月31日，价值7亿美元、比例为4875%的优先票据的票面价值为7亿美元，扣除60万美元的未摊销折扣，估算利率为4.88%。
[2] 在2014年第四季度，我们以40.25%的折扣购买了1000万美元的4.80%的优先票据，这导致了400万美元的债务清偿收益。截至2014年12月31日，这5亿美元4.80%的优先票据的票面价值为4.9亿美元，扣除60万美元的未摊销折扣，基于4.83%的估算利率。截至2013年12月31日，5亿美元4.80%的优先票据的票面价值为5亿美元减去80万美元的未摊销折扣，基于4.83%的估算利率。
[3] 截至2014年12月31日和2013年12月31日，按6.34%的估算利率，8亿美元6.25%的优先票据的票面价值分别为8亿美元减去未摊销折扣950万美元和960万美元。
[4] 在2014年第四季度，我们以38.125%的折扣购买了价值500万美元的5.90%未偿优先票据，从而获得190万美元的债务清偿收益。截至2014年12月31日，4亿美元5.90%的优先票据的票面价值为3.95亿美元减去130万美元的未摊销折扣，基于5.98%的估算利率。截至2013年12月31日，4亿美元5.90%的优先票据的票面价值为4亿美元减去160万美元的未摊销折扣，基于5.98%的估算利率。
[5] 在2014年第四季度，我们以30.875%的折扣率购买了2000万美元的3.95%优先票据，从而获得了620万美元的债务清偿收益。截至2014年12月31日，根据5.17%的估算利率，5亿美元3.95%的优先票据的票面价值为4.8亿美元减去260万美元的未摊销折扣。截至2013年12月31日，5亿美元3.95%的优先票据的票面价值为5亿美元减去350万美元的未摊销折扣，估算利率为4.14%。
[6] 截至2014年12月31日和2013年12月31日，该信贷额度下没有提取循环贷款。截至2014年12月31日和2013年12月31日，我们的信贷额度分别为11.25亿美元和17.5亿美元。此外，截至2014年12月31日和2013年12月31日，信用证债务的本金总额分别为1.495亿美元和840万美元，从而将每个时期的可用借款能力分别减少到10亿美元和17亿美元。