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（用以确定福利义务的加权平均假设）（详情）

v2.4.1.9
退休金及其他退休后福利（用以确定福利义务的加权平均假设）（详情）
2014年12月31日
2013年12月31日
养恤金福利[成员]|皇冠体育官网[成员]    
设定受益计划及其他退休后福利计划表    
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
计划资产的预期回报率 8.25%clf_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationReturnOnPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember 		8.25%clf_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationReturnOnPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember
养老金福利[成员]|加拿大[成员]    
设定受益计划及其他退休后福利计划表    
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
计划资产的预期回报率 7.25%clf_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationReturnOnPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_CanadaMember 		7.25%clf_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationReturnOnPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_CanadaMember
其他福利[成员]|皇冠体育官网[成员]    
设定受益计划及其他退休后福利计划表    
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
计划资产的预期回报率 7.00%clf_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationReturnOnPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember 		7.00%clf_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationReturnOnPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember
其他福利[成员]|加拿大[成员]    
设定受益计划及其他退休后福利计划表    
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
工资[成员]b|养老金福利[成员]|皇冠体育官网[成员]    
设定受益计划及其他退休后福利计划表    
薪酬增长率 3.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember
/ clf_TypeofCompensationAxis
= clf_SalaryMember 		4.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember
/ clf_TypeofCompensationAxis
= clf_SalaryMember
工资[成员]b|养老金福利[成员]|加拿大[成员]    
设定受益计划及其他退休后福利计划表    
薪酬增长率 3.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_CanadaMember
/ clf_TypeofCompensationAxis
= clf_SalaryMember 		4.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_CanadaMember
/ clf_TypeofCompensationAxis
= clf_SalaryMember
每小时[会员]|退休金福利[会员]    
设定受益计划及其他退休后福利计划表    
薪酬增长率 2.50%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_TypeofCompensationAxis
= clf_HourlyMember 		3.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_TypeofCompensationAxis
= clf_HourlyMember