根据第13和15(d)条提交的年度报告

退休金及其他退休后福利（叙述）（详情）

v2.4.1.9
养老金及其他退休后福利（说明）（详情）（美元）
12个月结束
2014年12月31日
2013年12月31日
2012年12月31日
2014年9月30日
设定受益计划披露〔分项〕        
本财政年度结束日期 ——12-31      
最低参与者百分比 15.00%clf_MinimumParticipantsCostPercentageToAverageCoverageCost      
固定收益养老金计划的累积收益义务 1204400000美元us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation 1091400000美元us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation    
证券成熟期 10年      
投资承诺准备金 55500000年clf_ReserveForInvestmentCommitments     45000000年clf_ReserveForInvestmentCommitments
Sei特别情况基金〔成员〕        
设定受益计划披露〔分项〕        
赎回请求通知期，天 95天      
结构性融资〔委员〕        
设定受益计划披露〔分项〕        
赎回请求通知期，天 90天      
房地产〔成员〕        
设定受益计划披露〔分项〕        
赎回请求通知期，天 45天      
撤回请求通知期，天 65天      
退休金福利〔成员〕        
设定受益计划披露〔分项〕        
由于新的死亡率表，预计养恤金义务增加 30000000年clf_IncreaseinProjectedBenefitObligationduetonewmortalitytables
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		     
由于新的死亡率表，预计养恤金义务增加的百分比 4.00%clf_PercentageIncreaseinProjectedBenefitObligationduetonewmortalitytables
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		     
固定收益计划，净定期收益成本 31300000年us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		52100000年us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		55200000年us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		 
固定供款计划的年度成本 6300000年us-gaap_DefinedContributionPlanCostRecognized
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		6800000年us-gaap_DefinedContributionPlanCostRecognized
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		6700000年us-gaap_DefinedContributionPlanCostRecognized
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		 
参与者的贡献 0us-gaap_DefinedBenefitPlanContributionsByPlanParticipants
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		0us-gaap_DefinedBenefitPlanContributionsByPlanParticipants
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		   
其他退休福利费用 (700000)us-gaap_OtherPostretirementBenefitExpense
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		17400000年us-gaap_OtherPostretirementBenefitExpense
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		28100000年us-gaap_OtherPostretirementBenefitExpense
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		 
养老金和其他退休福利费用 36900000年us-gaap_PensionAndOtherPostretirementBenefitExpense
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		76300000年us-gaap_PensionAndOtherPostretirementBenefitExpense
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		90000000年us-gaap_PensionAndOtherPostretirementBenefitExpense
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		 
固定收益计划，因缩减而确认的净收益（损失） (10900000)us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToCurtailments
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		0us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToCurtailments
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		   
由于新的死亡率表，加拿大计划预计福利义务增加 12000000年clf_IncreaseinCanadianPlanProjectedBenefitObligationduetonewmortalitytables
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		     
由于新的死亡率表，加拿大计划预计福利义务的百分比增加 5.00%clf_PercentageIncreaseinCanadianPlanProjectedBenefitObligationduetonewmortalitytables
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		     
固定收益计划，因结算和缩减而确认的净收益（损失） (2900000)us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments1
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		0us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments1
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		0us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments1
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember 		 
其他福利[成员]        
设定受益计划披露〔分项〕        
由于新的死亡率表，预计养恤金义务增加 20000000年clf_IncreaseinProjectedBenefitObligationduetonewmortalitytables
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember 		     
由于新的死亡率表，预计养恤金义务增加的百分比 7.00%clf_PercentageIncreaseinProjectedBenefitObligationduetonewmortalitytables
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember 		     
固定收益计划，净定期收益成本 (700000)us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember 		17400000年us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember 		28100000年us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember 		 
参与者的贡献 4800000年us-gaap_DefinedBenefitPlanContributionsByPlanParticipants
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember 		5600000年us-gaap_DefinedBenefitPlanContributionsByPlanParticipants
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember 		   
固定收益计划，因缩减而确认的净收益（损失） (8800000)us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToCurtailments
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember 		0us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToCurtailments
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember 		   
由于新的死亡率表，加拿大计划预计福利义务增加 3000000年clf_IncreaseinCanadianPlanProjectedBenefitObligationduetonewmortalitytables
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember 		     
由于新的死亡率表，加拿大计划预计福利义务的百分比增加 5.00%clf_PercentageIncreaseinCanadianPlanProjectedBenefitObligationduetonewmortalitytables
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember 		     
固定收益计划，因结算和缩减而确认的净收益（损失） 7900000年us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments1
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember 		0us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments1
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember 		0us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments1
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember 		 
最低(成员)        
设定受益计划披露〔分项〕        
折现率 3.72%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_RangeAxis
= us-gaap_MinimumMember 		     
预期长期资产回报率 3年      
最大(成员)        
设定受益计划披露〔分项〕        
折现率 3.92%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_RangeAxis
= us-gaap_MaximumMember 		     
预期长期资产回报率 5年      
皇冠体育官网[成员]b|养恤金福利[成员]        
设定受益计划披露〔分项〕        
折现率 3.83%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember 		4.57%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember 		   
预计收益，使用的债券数量 715clf_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRateNumberOfBondsUsedForProjectedYieldCurve
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember 		     
皇冠体育官网[成员]b|其他福利[成员]        
设定受益计划披露〔分项〕        
折现率 3.83%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember 		4.57%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember 		   
加拿大[成员]|退休金福利[成员]        
设定受益计划披露〔分项〕        
折现率 3.75%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_CanadaMember 		4.50%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_CanadaMember 		   
预计收益，使用的债券数量 285clf_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRateNumberOfBondsUsedForProjectedYieldCurve
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_CanadaMember 		     
加拿大[成员]b|其他福利[成员]        
设定受益计划披露〔分项〕        
折现率 3.75%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_CanadaMember 		4.75%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_CanadaMember 		   
Tilden, Empire， Hibbing and United Taconite[成员]        
设定受益计划披露〔分项〕        
受劳动合同保护的USW雇员人数 2200年clf_NumberOfEmployeesInUnionCoveredByAnyUnionAgreement
/ clf_MineLocationAxis
= clf_TildenEmpireHibbingandUnitedTaconiteMember 		     
劳动合同涵盖的劳动力总数的百分比 40.90%clf_PercentageOfTotalWorkforceUnderLaborContract
/ clf_MineLocationAxis
= clf_TildenEmpireHibbingandUnitedTaconiteMember 		     
Pinnacle Complex and Oak Grove[成员]        
设定受益计划披露〔分项〕        
受劳动合同保护的USW雇员人数 800clf_NumberOfEmployeesInUnionCoveredByAnyUnionAgreement
/ clf_MineLocationAxis
= clf_PinnacleComplexandOakGroveMember 		     
劳动合同涵盖的劳动力总数的百分比 15.20%clf_PercentageOfTotalWorkforceUnderLaborContract
/ clf_MineLocationAxis
= clf_PinnacleComplexandOakGroveMember 		     
每小时工作贡献率 8.16clf_DefinedContributionPlanRates
/ clf_MineLocationAxis
= clf_PinnacleComplexandOakGroveMember 		8.10clf_DefinedContributionPlanRates
/ clf_MineLocationAxis
= clf_PinnacleComplexandOakGroveMember 		8.10clf_DefinedContributionPlanRates
/ clf_MineLocationAxis
= clf_PinnacleComplexandOakGroveMember 		 
固定供款计划的年度成本 14900000年us-gaap_DefinedContributionPlanCostRecognized
/ clf_MineLocationAxis
= clf_PinnacleComplexandOakGroveMember 		13800000年us-gaap_DefinedContributionPlanCostRecognized
/ clf_MineLocationAxis
= clf_PinnacleComplexandOakGroveMember 		   
资金不足负债估计 330000000年clf_UnderfundedLiabilityEstimate
/ clf_MineLocationAxis
= clf_PinnacleComplexandOakGroveMember 		     
65岁以前[成员]|退休后固定福利医疗保险[成员]|皇冠体育官网[成员]        
设定受益计划披露〔分项〕        
每位参加者每年的医疗保险限额 7000年clf_PostretirementBenefitsMedicalCoverageAnnualLimit
/ clf_CoverageAgeAxis
= clf_PriorToAge65Member
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementHealthCoverageMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= country_US 		     
65岁以前[成员]|最低限额[成员]|固定给付退休后健康保险[成员]|北岸[成员]        
设定受益计划披露〔分项〕        
每位参加者每年的医疗保险限额 4020年clf_PostretirementBenefitsMedicalCoverageAnnualLimit
/ clf_CoverageAgeAxis
= clf_PriorToAge65Member
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementHealthCoverageMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= clf_NorthshoreMember 		     
65岁以前[成员]|最高限额[成员]|固定给付退休后健康保险[成员]|北岸[成员]        
设定受益计划披露〔分项〕        
每位参加者每年的医疗保险限额 4500年clf_PostretirementBenefitsMedicalCoverageAnnualLimit
/ clf_CoverageAgeAxis
= clf_PriorToAge65Member
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementHealthCoverageMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= clf_NorthshoreMember 		     
65岁以后[成员]|退休后固定福利医疗保险[成员]|皇冠体育官网[成员]        
设定受益计划披露〔分项〕        
每位参加者每年的医疗保险限额 3,000clf_PostretirementBenefitsMedicalCoverageAnnualLimit
/ clf_CoverageAgeAxis
= clf_AfterAge65Member
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementHealthCoverageMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= country_US 		     
65岁以后[成员]|固定给付退休后健康保险[成员]| Northshore[成员]        
设定受益计划披露〔分项〕        
每位参加者每年的医疗保险限额 2000美元clf_PostretirementBenefitsMedicalCoverageAnnualLimit
/ clf_CoverageAgeAxis
= clf_AfterAge65Member
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementHealthCoverageMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= clf_NorthshoreMember