根据第13或15(d)条提交的季度报告

衍生工具及套期保值活动（叙述）（详情）

v2.4.1.9
衍生工具及套期保值活动（说明）（详情）（美元）
除非另有说明，单位为百万
3个月结束 12个月结束
2015年3月31日
2014年3月31日
2014年12月31日
2014.6.30
衍生品〔单行项目〕        
未指定为套期工具的衍生工具，收益（损失），净额 (15.6美元)us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet 24.1美元us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet    
衍生工具，收益（损失）从累积OCI重新分类为收益，有效部分，净额 (6.3)us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet (12.8)us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet    
指定前的加元外汇合约对冲[成员]        
衍生品〔单行项目〕        
衍生工具，收益（损失）从累积OCI重新分类为收益，有效部分，净额 0us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_CanadianDollarForeignExchangeContractsHedgePriortoDeDesignationMember 		(0.3)us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_CanadianDollarForeignExchangeContractsHedgePriortoDeDesignationMember 		   
利率掉期〔成员〕b|其他营业外收入（费用）〔成员〕        
衍生品〔单行项目〕        
公允价值套期无效损益，净额   0.2us-gaap_GainLossOnFairValueHedgeIneffectivenessNet
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateSwapMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_OtherNonoperatingIncomeExpenseMember 		   
利率掉期〔成员〕b|指定为套期保值工具〔成员〕        
衍生品〔单行项目〕        
衍生品，名义金额       250.0invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateSwapMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember
澳元外汇合约套期保值指定【会员】|产品收益【会员】        
衍生品〔单行项目〕        
衍生工具，收益（损失）从累积OCI重新分类为收益，有效部分，净额 (6.3)us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_AustralianDollarForeignExchangeContractHedgeDesignationMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_SalesRevenueGoodsNetMember 		(9.1)us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_AustralianDollarForeignExchangeContractHedgeDesignationMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_SalesRevenueGoodsNetMember 		   
澳洲元外汇合约指定套期保值工具〔成员〕        
衍生品〔单行项目〕        
衍生品，名义金额 20.0invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_AustralianDollarForeignExchangeContractHedgeDesignationMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember 		  220.0invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_AustralianDollarForeignExchangeContractHedgeDesignationMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember 		 
澳元外汇合约套期保值指定[成员]|指定为套期保值工具[成员]|其他累积综合收益（损失）[成员]        
衍生品〔单行项目〕        
相关合同结算后，将在未来12个月内重新分类为产品收入的金额 (2.2)us-gaap_ForeignCurrencyCashFlowHedgeGainLossToBeReclassifiedDuringNext12Months
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_AustralianDollarForeignExchangeContractHedgeDesignationMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember 		     
未指定前澳元外汇合约【会员】|未指定为套期保值工具【会员】|累计其他综合收益（损失）【会员】        
衍生品〔单行项目〕        
相关合同结算后，将在未来12个月内重新分类为产品收入的金额 (12.5)us-gaap_ForeignCurrencyCashFlowHedgeGainLossToBeReclassifiedDuringNext12Months
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_AustralianDollarForeignExchangeContractsDedesignatedMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember 		     
加拿大元外汇合约套期保值指定【会员】|销售成本【会员】        
衍生品〔单行项目〕        
衍生工具，收益（损失）从累积OCI重新分类为收益，有效部分，净额 0us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_CanadianDollarForeignExchangeContractsHedgeDesignationMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_CostOfSalesMember 		(3.4)us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_CanadianDollarForeignExchangeContractsHedgeDesignationMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_CostOfSalesMember 		   
加拿大元外汇合约对冲指定[成员][成员]|非指定对冲工具[成员]        
衍生品〔单行项目〕        
衍生品，名义金额 0invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_CanadianDollarForeignExchangeContractsHedgeDeDesignatedMemberMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember 		  0invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_CanadianDollarForeignExchangeContractsHedgeDeDesignatedMemberMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember 		 
外汇合同【成员】b|其他营业外收入（费用）【成员】        
衍生品〔单行项目〕        
未指定为套期工具的衍生工具，收益（损失），净额 (5.9)us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_ForeignExchangeContractMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_OtherNonoperatingIncomeExpenseMember 		[1] (0.9)us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_ForeignExchangeContractMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_OtherNonoperatingIncomeExpenseMember 		[1]    
客户供应协议[成员]|未指定为套期保值工具[成员]|产品收入[成员]        
衍生品〔单行项目〕        
在衍生工具收益中确认的利得/（损失）金额 10.1us-gaap_DerivativeGainLossOnDerivativeNet
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_CustomerSupplyAgreementMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_SalesRevenueGoodsNetMember 		27.7us-gaap_DerivativeGainLossOnDerivativeNet
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_CustomerSupplyAgreementMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_SalesRevenueGoodsNetMember 		   
客户供应协议[成员]|未指定为套期保值工具[成员]|衍生金融工具、资产[成员]        
衍生品〔单行项目〕        
衍生品资产 34.5us-gaap_DerivativeAssetsCurrent
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_DerivativeFinancialInstrumentsAssetsMember
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_CustomerSupplyAgreementMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember 		  63.2us-gaap_DerivativeAssetsCurrent
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_DerivativeFinancialInstrumentsAssetsMember
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_CustomerSupplyAgreementMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember 		 
临时定价安排[成员]b|产品收入[成员]        
衍生品〔单行项目〕        
未指定为套期工具的衍生工具，收益（损失），净额 (16.2)us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_ProvisionalPricingArrangementsMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_SalesRevenueGoodsNetMember 		(2.7)us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_ProvisionalPricingArrangementsMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_SalesRevenueGoodsNetMember 		   
临时定价安排[成员]|未被指定为套期保值工具[成员]|皇冠体育官网铁矿石及亚太铁矿石[成员]|产品收入[成员]        
衍生品〔单行项目〕        
在衍生工具收益中确认的利得/（损失）金额 (16.2)us-gaap_DerivativeGainLossOnDerivativeNet
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_ProvisionalPricingArrangementsMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_SalesRevenueGoodsNetMember
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreAndAsiaPacificIronOreMember 		(2.7)us-gaap_DerivativeGainLossOnDerivativeNet
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_ProvisionalPricingArrangementsMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_SalesRevenueGoodsNetMember
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreAndAsiaPacificIronOreMember 		   
临时定价安排[成员]|未指定为套期保值工具[成员]|皇冠体育官网铁矿石及亚太地区铁矿石[成员]|衍生金融工具、资产[成员]        
衍生品〔单行项目〕        
衍生品资产 0us-gaap_DerivativeAssetsCurrent
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_DerivativeFinancialInstrumentsAssetsMember
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_ProvisionalPricingArrangementsMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreAndAsiaPacificIronOreMember 		     
临时定价安排[成员]b|未指定为套期保值工具[成员]|皇冠体育官网铁矿石及亚太铁矿石[成员]|衍生金融工具、负债[成员]        
衍生品〔单行项目〕        
导数的负债 16.2us-gaap_DerivativeLiabilitiesCurrent
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_ProvisionalPricingArrangementsMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreAndAsiaPacificIronOreMember 		  9.5us-gaap_DerivativeLiabilitiesCurrent
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_ProvisionalPricingArrangementsMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
/ us-gaap_StatementBusinessSegmentsAxis
= clf_USIronOreAndAsiaPacificIronOreMember 		 
企业【会员】|指定前加元外汇合约套期保值【会员】        
衍生品〔单行项目〕        
衍生工具，收益（损失）从累积OCI重新分类为收益，有效部分，净额   0.3us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_CanadianDollarForeignExchangeContractsHedgePriortoDeDesignationMember
/ clf_ReportingUnitAxis
= us-gaap_CorporateMember 		   
公司[成员]b|加拿大元外汇合约指定对冲[成员][成员]b|非指定对冲工具[成员]        
衍生品〔单行项目〕        
衍生品，名义金额 41.4invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_CanadianDollarForeignExchangeContractsHedgeDeDesignatedMemberMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
/ clf_ReportingUnitAxis
= us-gaap_CorporateMember 		  183.0invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= clf_CanadianDollarForeignExchangeContractsHedgeDeDesignatedMemberMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
/ clf_ReportingUnitAxis
= us-gaap_CorporateMember 		 
公司[成员]|外汇合同[成员]|销售成本[成员]        
衍生品〔单行项目〕        
未指定为套期工具的衍生工具，收益（损失），净额   0.9美元us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_ForeignExchangeContractMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_CostOfSalesMember
/ clf_ReportingUnitAxis
= us-gaap_CorporateMember 		(7.3美元)us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_ForeignExchangeContractMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_CostOfSalesMember
/ clf_ReportingUnitAxis
= us-gaap_CorporateMember 		 
[1] 2014年3月31日，外汇合约衍生品收益确认的利得（损失）位置为销售货物成本和营业费用。