XML 125 R108.htm IDEA: XBRL DOCUMENT v2.4.1.9
Investments (Mortgage Loans - Narrative) (Details) (USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]      
Impaired Financing Receivable, Average Recorded Investment $ 391,000,000us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment $ 583,000,000us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment  
Financing Receivable, Significant Purchases 4,700,000,000us-gaap_FinancingReceivableSignificantPurchases 2,200,000,000us-gaap_FinancingReceivableSignificantPurchases  
Percentage of Mortgage Loans Classified as Performing 99.00%mlic_PercentageOfMortgageLoansClassifiedAsPerforming 99.00%mlic_PercentageOfMortgageLoansClassifiedAsPerforming  
Agricultural      
Financing Receivable, Recorded Investment [Line Items]      
Impaired Financing Receivable, Average Recorded Investment     201,000,000us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mlic_AgriculturalPortfolioSegmentMember
Estimated fair value of mortgage loans held-for-investment 11,400,000,000us-gaap_NotesReceivableNet
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mlic_AgriculturalPortfolioSegmentMember
11,300,000,000us-gaap_NotesReceivableNet
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= mlic_AgriculturalPortfolioSegmentMember
 
Commercial Loan [Member]      
Financing Receivable, Recorded Investment [Line Items]      
Impaired Financing Receivable, Average Recorded Investment     384,000,000us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
Residential      
Financing Receivable, Recorded Investment [Line Items]      
Impaired Financing Receivable, Average Recorded Investment     0us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
Estimated fair value of mortgage loans held-for-investment $ 5,600,000,000us-gaap_NotesReceivableNet
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
$ 1,800,000,000us-gaap_NotesReceivableNet
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember