XML 224 R191.htm IDEA: XBRL DOCUMENT v2.4.1.9
Employee Benefit Plans (Actual & Target Allocation of Fair Value by Asset Class) (Details)
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Pension Benefits U.S. Plans [Member]    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Actual 100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember		 100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember
Pension Benefits U.S. Plans [Member] | Fixed Maturity Securities    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Target 75.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember		  
Actual 69.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember		 64.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember
Pension Benefits U.S. Plans [Member] | Equity securities    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Target 12.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember		  
Actual 15.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember		 23.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember
Pension Benefits U.S. Plans [Member] | Alternative Securities [Member]    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Target 13.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= met_AlternativeSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember		  
Actual 16.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= met_AlternativeSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember		 13.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= met_AlternativeSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember
Pension Benefits Non-U.S. Plans [Member]    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Actual 100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember		 100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
Pension Benefits Non-U.S. Plans [Member] | Fixed Maturity Securities    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Target 74.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember		  
Actual 61.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember		 50.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
Pension Benefits Non-U.S. Plans [Member] | Equity securities    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Target 19.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember		  
Actual 23.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember		 33.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
Pension Benefits Non-U.S. Plans [Member] | Alternative Securities [Member]    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Target 7.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= met_AlternativeSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember		  
Actual 16.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= met_AlternativeSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember		 17.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= met_AlternativeSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
Other Postretirement Benefits U.S. Plans [Member] | Postretirement Medical    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Actual 100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementHealthCoverageMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember		 100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementHealthCoverageMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
Other Postretirement Benefits U.S. Plans [Member] | Postretirement Medical | Fixed Maturity Securities    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Target 70.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementHealthCoverageMember
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember		  
Actual 71.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementHealthCoverageMember
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember		 67.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementHealthCoverageMember
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
Other Postretirement Benefits U.S. Plans [Member] | Postretirement Medical | Equity securities    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Target 30.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementHealthCoverageMember
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember		  
Actual 27.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementHealthCoverageMember
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember		 32.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementHealthCoverageMember
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
Other Postretirement Benefits U.S. Plans [Member] | Postretirement Medical | Alternative Securities [Member]    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Target 0.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementHealthCoverageMember
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= met_AlternativeSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember		  
Actual 2.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementHealthCoverageMember
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= met_AlternativeSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember		 1.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementHealthCoverageMember
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= met_AlternativeSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
Other Postretirement Benefits U.S. Plans [Member] | Postretirement Life Insurance [Member]    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Actual 100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementLifeInsuranceMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember		 100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementLifeInsuranceMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
Other Postretirement Benefits U.S. Plans [Member] | Postretirement Life Insurance [Member] | Fixed Maturity Securities    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Target 0.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementLifeInsuranceMember
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember		  
Actual 0.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementLifeInsuranceMember
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember		 0.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementLifeInsuranceMember
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
Other Postretirement Benefits U.S. Plans [Member] | Postretirement Life Insurance [Member] | Equity securities    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Target 0.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementLifeInsuranceMember
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember		  
Actual 0.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementLifeInsuranceMember
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember		 0.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementLifeInsuranceMember
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
Other Postretirement Benefits U.S. Plans [Member] | Postretirement Life Insurance [Member] | Alternative Securities [Member]    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Target 100.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementLifeInsuranceMember
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= met_AlternativeSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember		  
Actual 100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementLifeInsuranceMember
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= met_AlternativeSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember		 100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis
= us-gaap_DefinedBenefitPostretirementLifeInsuranceMember
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= met_AlternativeSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
Other Postretirement Benefits Non-U.S. Plans [Member]    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Actual 100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPostretirementBenefitPlansDefinedBenefitMember		 100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPostretirementBenefitPlansDefinedBenefitMember
Other Postretirement Benefits Non-U.S. Plans [Member] | Fixed Maturity Securities    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Target 100.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPostretirementBenefitPlansDefinedBenefitMember		  
Actual 100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPostretirementBenefitPlansDefinedBenefitMember		 100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPostretirementBenefitPlansDefinedBenefitMember
Other Postretirement Benefits Non-U.S. Plans [Member] | Equity securities    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Target 0.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPostretirementBenefitPlansDefinedBenefitMember		  
Actual 0.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPostretirementBenefitPlansDefinedBenefitMember		 0.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPostretirementBenefitPlansDefinedBenefitMember
Other Postretirement Benefits Non-U.S. Plans [Member] | Alternative Securities [Member]    
Actual weighted average asset allocation by major asset class for the Invested Plans [Abstract]    
Target 0.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= met_AlternativeSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPostretirementBenefitPlansDefinedBenefitMember		  
Actual 0.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= met_AlternativeSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPostretirementBenefitPlansDefinedBenefitMember		 0.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= met_AlternativeSecuritiesMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPostretirementBenefitPlansDefinedBenefitMember