v3.8.0.1
Schedule I - Summary of Investments Other Than investments in Related Parties (Details) - USD ($)
$ in Millions
Dec. 31, 2017
Dec. 31, 2016
Schedule of Investments [Line Items]    
Amortized Cost $ 312,385 $ 292,581
Fair Value [1] 346,780 321,419
Fixed maturities, held-to-maturity [1] 2,049 2,144
Fixed maturities, held to maturity, fair value 2,430 2,524
Equity Security at Cost 4,147 7,149
Equity securities, available-for-sale 6,174 9,748
Fair Value [1] 22,097 21,840
Commercial mortgage and other loans [1] 56,045 52,779
Policy loans 11,891 11,755
Short-term investments 6,775 7,508
Other Long-term Investments [1] 12,308 11,283
Total Investment at Cost 433,449  
Total investment per Balance Sheet 469,871 444,240
Fixed Maturities    
Schedule of Investments [Line Items]    
Amortized Cost 312,385 292,581
Fair Value 346,780 321,419
Fixed maturities, held-to-maturity 2,049 2,144
Fixed maturities, held to maturity, fair value 2,430 2,524
Fair Value 20,209 19,850
Equity securities    
Schedule of Investments [Line Items]    
Equity Security at Cost 4,147 7,149
Equity securities, available-for-sale 6,174 9,748
Fair Value 1,643 1,335
Available-for-sale | Fixed Maturities    
Schedule of Investments [Line Items]    
Amortized Cost 312,385  
Fair Value 346,780  
Available-for-sale | Equity securities    
Schedule of Investments [Line Items]    
Equity Security at Cost 4,147  
Equity securities, available-for-sale 6,174  
Held-to-maturity | Fixed Maturities    
Schedule of Investments [Line Items]    
Fixed maturities, held-to-maturity 2,049  
Fixed maturities, held to maturity, fair value 2,430  
U.S. Treasury securities and obligations of U.S. government authorities and agencies | Fixed Maturities    
Schedule of Investments [Line Items]    
Amortized Cost 22,837 21,505
Fair Value 26,138 23,784
U.S. Treasury securities and obligations of U.S. government authorities and agencies | Available-for-sale | Fixed Maturities    
Schedule of Investments [Line Items]    
Amortized Cost 22,837  
Fair Value 26,138  
Obligations of U.S. states and their political subdivisions | Fixed Maturities    
Schedule of Investments [Line Items]    
Amortized Cost 9,366 9,060
Fair Value 10,471 9,692
Obligations of U.S. states and their political subdivisions | Available-for-sale | Fixed Maturities    
Schedule of Investments [Line Items]    
Amortized Cost 9,366  
Fair Value 10,471  
Foreign governments | Available-for-sale | Fixed Maturities    
Schedule of Investments [Line Items]    
Amortized Cost 88,062  
Fair Value 103,419  
Foreign governments | Held-to-maturity | Fixed Maturities    
Schedule of Investments [Line Items]    
Fixed maturities, held-to-maturity 865  
Fixed maturities, held to maturity, fair value 1,130  
Asset-backed securities | Fixed Maturities    
Schedule of Investments [Line Items]    
Amortized Cost 11,965 11,759
Fair Value 12,233 11,935
Fair Value 1,392 1,349
Asset-backed securities | Available-for-sale | Fixed Maturities    
Schedule of Investments [Line Items]    
Amortized Cost 11,965  
Fair Value 12,233  
Residential mortgage-backed securities | Fixed Maturities    
Schedule of Investments [Line Items]    
Amortized Cost 3,491 4,308
Fair Value 3,645 4,532
Fixed maturities, held-to-maturity 446 573
Fixed maturities, held to maturity, fair value 478 616
Fair Value 966 1,150
Residential mortgage-backed securities | Available-for-sale | Fixed Maturities    
Schedule of Investments [Line Items]    
Amortized Cost 3,491  
Fair Value 3,645  
Residential mortgage-backed securities | Held-to-maturity | Fixed Maturities    
Schedule of Investments [Line Items]    
Fixed maturities, held-to-maturity 446  
Fixed maturities, held to maturity, fair value 478  
Commercial Mortgage Backed Securities | Fixed Maturities    
Schedule of Investments [Line Items]    
Amortized Cost 13,134 12,589
Fair Value 13,281 12,704
Fixed maturities, held-to-maturity 0 0
Fixed maturities, held to maturity, fair value 0 0
Fair Value 2,311 $ 2,052
Commercial Mortgage Backed Securities | Available-for-sale | Fixed Maturities    
Schedule of Investments [Line Items]    
Amortized Cost 13,134  
Fair Value 13,281  
Commercial Mortgage Backed Securities | Held-to-maturity | Fixed Maturities    
Schedule of Investments [Line Items]    
Fixed maturities, held-to-maturity 0  
Fixed maturities, held to maturity, fair value 0  
Public utilities | Available-for-sale | Fixed Maturities    
Schedule of Investments [Line Items]    
Amortized Cost 26,169  
Fair Value 28,723  
Certificates of deposit | Available-for-sale | Fixed Maturities    
Schedule of Investments [Line Items]    
Amortized Cost 30  
Fair Value 31  
All other corporate bonds | Available-for-sale | Fixed Maturities    
Schedule of Investments [Line Items]    
Amortized Cost 136,805  
Fair Value 148,250  
All other corporate bonds | Held-to-maturity | Fixed Maturities    
Schedule of Investments [Line Items]    
Fixed maturities, held-to-maturity 738  
Fixed maturities, held to maturity, fair value 822  
Redeemable preferred stock | Available-for-sale | Fixed Maturities    
Schedule of Investments [Line Items]    
Amortized Cost 526  
Fair Value 589  
Public utilities | Available-for-sale | Equity securities    
Schedule of Investments [Line Items]    
Equity Security at Cost 93  
Equity securities, available-for-sale 117  
Banks, trust and insurance companies | Available-for-sale | Equity securities    
Schedule of Investments [Line Items]    
Equity Security at Cost 929  
Equity securities, available-for-sale 1,428  
Industrial, miscellaneous and other | Available-for-sale | Equity securities    
Schedule of Investments [Line Items]    
Equity Security at Cost 3,109  
Equity securities, available-for-sale 4,612  
Nonredeemable preferred stock | Available-for-sale | Equity securities    
Schedule of Investments [Line Items]    
Equity Security at Cost 16  
Equity securities, available-for-sale 17  
Other trading account assets    
Schedule of Investments [Line Items]    
Fair Value 5,752  
Commercial mortgage and agricultural properties loans and other collateralized loans    
Schedule of Investments [Line Items]    
Commercial mortgage and other loans 55,387  
Uncollateralized loans    
Schedule of Investments [Line Items]    
Commercial mortgage and other loans $ 658  
[1] See Note 5 for details of balances associated with variable interest entities.