XML 40 R133.htm IDEA: XBRL DOCUMENT v2.4.1.9
Fair Value (Fair Value Option for Long-term Debt) (Details) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Fair Value, Option, Quantitative Disclosures [Line Items]    
Carrying value at estimated fair value $ 2,027us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities $ 2,828us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities
Long-term debt    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Contractual principal balance 115us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= us-gaap_LongTermDebtMember		 123us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= us-gaap_LongTermDebtMember
Difference between estimated fair value and contractual principal balance 2us-gaap_FairValueOptionAggregateDifferencesLongTermDebtInstruments
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= us-gaap_LongTermDebtMember		 (1)us-gaap_FairValueOptionAggregateDifferencesLongTermDebtInstruments
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= us-gaap_LongTermDebtMember
Carrying value at estimated fair value 117us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= us-gaap_LongTermDebtMember		 122us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= us-gaap_LongTermDebtMember
Consolidated Securitization Entities    
Fair Value, Option, Quantitative Disclosures [Line Items]    
Contractual principal balance 26us-gaap_DebtInstrumentCarryingAmount
/ dei_LegalEntityAxis
= mlic_VariableInterestEntityPrimaryBeneficiaryConsolidatedSecuritizationEntitiesMember		 42us-gaap_DebtInstrumentCarryingAmount
/ dei_LegalEntityAxis
= mlic_VariableInterestEntityPrimaryBeneficiaryConsolidatedSecuritizationEntitiesMember
Difference between estimated fair value and contractual principal balance (13)us-gaap_FairValueOptionAggregateDifferencesLongTermDebtInstruments
/ dei_LegalEntityAxis
= mlic_VariableInterestEntityPrimaryBeneficiaryConsolidatedSecuritizationEntitiesMember		 (14)us-gaap_FairValueOptionAggregateDifferencesLongTermDebtInstruments
/ dei_LegalEntityAxis
= mlic_VariableInterestEntityPrimaryBeneficiaryConsolidatedSecuritizationEntitiesMember
Carrying value at estimated fair value $ 13us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities
/ dei_LegalEntityAxis
= mlic_VariableInterestEntityPrimaryBeneficiaryConsolidatedSecuritizationEntitiesMember		 $ 28us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities
/ dei_LegalEntityAxis
= mlic_VariableInterestEntityPrimaryBeneficiaryConsolidatedSecuritizationEntitiesMember