Schedule I Summary of Investments - Other than Investments in Related Parties (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	$ 336,450
Fair Value	358,108
Amount at which shown in the Balance Sheet	357,370
Fixed maturity securities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	263,019
Fair Value	279,571
Amount at which shown in the Balance Sheet	279,571
U.S. government and government sponsored entities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	8,304
Fair Value	8,490
Amount at which shown in the Balance Sheet	8,490
Obligations of states, municipalities and political subdivisions
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	26,101
Fair Value	27,781
Amount at which shown in the Balance Sheet	27,781
Non-U.S. government
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	20,282
Fair Value	21,097
Amount at which shown in the Balance Sheet	21,097
Public utilities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	21,712
Fair Value	23,676
Amount at which shown in the Balance Sheet	23,676
All other corporate and debt securities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	113,968
Fair Value	121,476
Amount at which shown in the Balance Sheet	121,476
Mortgage-backed, asset-backed and collateralized
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	72,652
Fair Value	77,051
Amount at which shown in the Balance Sheet	77,051
Equity securities and mutual funds
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	2,979
Fair Value	5,444
Amount at which shown in the Balance Sheet	5,444
Common Stock
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	2,234
Fair Value	4,678
Amount at which shown in the Balance Sheet	4,678
Public utilities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	9
Fair Value	11
Amount at which shown in the Balance Sheet	11
Banks, trust and insurance companies
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	1,854
Fair Value	4,128
Amount at which shown in the Balance Sheet	4,128
Industrial, miscellaneous and all other
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	371
Fair Value	539
Amount at which shown in the Balance Sheet	539
Preferred stock
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	21
Fair Value	25
Amount at which shown in the Balance Sheet	25
Mutual funds
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	724
Fair Value	741
Amount at which shown in the Balance Sheet	741
Mortgage and other loans receivable, net of allowance
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	24,990
Fair Value	26,606
Amount at which shown in the Balance Sheet	24,990
Other invested assets
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	32,615
Fair Value	33,640
Amount at which shown in the Balance Sheet	34,518
Short-term investments, at cost (approximates fair value)
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	11,243
Fair Value	11,243
Amount at which shown in the Balance Sheet	11,243
Derivative assets
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	1,604
Fair Value	1,604
Amount at which shown in the Balance Sheet	$ 1,604