根据第13和15(d)条提交的年度报告

退休金和其他退休后福利（用于确定净福利成本的加权平均假设）（详情）

v2.4.1.9
退休金和其他退休后福利（用于确定净福利成本的加权平均假设）（详情）
12个月结束 2个月结束 10个月结束
2014年12月31日
2013年12月31日
2012年12月31日
2012年12月31日
2012年10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 4.57%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember 		3.70%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember 		4.28%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember 		   
计划资产的预期回报率 8.25%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember 		8.25%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember 		8.25%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
/ 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 4.50%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_CanadaMember 		3.75%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_CanadaMember 		4.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_CanadaMember 		   
计划资产的预期回报率 7.25%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_CanadaMember 		7.25%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_CanadaMember 		7.25%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
/ 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 4.57%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember 		3.70%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember 		     
计划资产的预期回报率 7.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember 		8.25%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember 		8.25%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
/ 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 4.75%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_CanadaMember 		4.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_CanadaMember 		4.25%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ clf_RegionReportingInformationByRegionAxis
= clf_CanadaMember 		   
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 4.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_TypeofCompensationAxis
= clf_HourlyMember 		4.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_TypeofCompensationAxis
= clf_HourlyMember 		4.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_TypeofCompensationAxis
= clf_HourlyMember 		   
工资【会员】|养老金【会员】          
设定受益计划及其他退休后福利计划表          
薪酬增长率 4.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_TypeofCompensationAxis
= clf_SalaryMember 		4.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_TypeofCompensationAxis
= clf_SalaryMember 		4.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ clf_TypeofCompensationAxis
= clf_SalaryMember 		   
薪酬[成员]b|其他福利[成员]          
设定受益计划及其他退休后福利计划表          
薪酬增长率 4.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ clf_TypeofCompensationAxis
= clf_SalaryMember 		4.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ clf_TypeofCompensationAxis
= clf_SalaryMember 		4.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ clf_TypeofCompensationAxis
= clf_SalaryMember 		   
受薪计划[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     4.28%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
/ clf_PlanTypeAxis
= clf_SalariedPlanMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember 		   
每小时收费计划[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       3.51%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
/ clf_PlanTypeAxis
= clf_HourlyPlanMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember 		4.28%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
/ clf_PlanTypeAxis
= clf_HourlyPlanMember
/ clf_RegionReportingInformationByRegionAxis
= clf_UnitedStatesMember