Schedule I Summary of Investments - Other than Investments in Related Parties (Details) $ in Millions	Dec. 31, 2015 USD ($)
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	$ 330,213
Fair Value	339,715
Amount at which shown in the Balance Sheet	339,663
Fixed maturity securities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	257,752
Fair Value	265,027
Amount at which shown in the Balance Sheet	265,027
U.S. government and government sponsored entities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	5,066
Fair Value	5,212
Amount at which shown in the Balance Sheet	5,212
Obligations of states, municipalities and political subdivisions
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	26,079
Fair Value	27,399
Amount at which shown in the Balance Sheet	27,399
Non-U.S. government
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	17,803
Fair Value	18,245
Amount at which shown in the Balance Sheet	18,245
Public utilities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	17,713
Fair Value	18,646
Amount at which shown in the Balance Sheet	18,646
All other corporate and debt securities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	117,835
Fair Value	119,377
Amount at which shown in the Balance Sheet	119,377
Mortgage-backed, asset-backed and collateralized
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	73,256
Fair Value	76,148
Amount at which shown in the Balance Sheet	76,148
Equity securities and mutual funds
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	2,300
Fair Value	3,836
Amount at which shown in the Balance Sheet	3,836
Common Stock
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	1,834
Fair Value	3,322
Amount at which shown in the Balance Sheet	3,322
Public utilities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	5
Fair Value	5
Amount at which shown in the Balance Sheet	5
Banks, trust and insurance companies
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	1,493
Fair Value	2,835
Amount at which shown in the Balance Sheet	2,835
Industrial, miscellaneous and all other
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	336
Fair Value	482
Amount at which shown in the Balance Sheet	482
Preferred stock
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	19
Fair Value	22
Amount at which shown in the Balance Sheet	22
Mutual funds
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	447
Fair Value	492
Amount at which shown in the Balance Sheet	492
Mortgage and other loans receivable, net of allowance
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	29,565
Fair Value	30,344
Amount at which shown in the Balance Sheet	29,565
Other invested assets
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	29,155
Fair Value	29,067
Amount at which shown in the Balance Sheet	29,794
Short-term investments, at cost
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	10,132
Fair Value	10,132
Amount at which shown in the Balance Sheet	10,132
Derivative assets
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	1,309
Fair Value	1,309
Amount at which shown in the Balance Sheet	$ 1,309