Investments (Distribution of Contractual Maturity Available for Sale) (Details) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Amortized cost	$ 11,249	$ 12,822
Fair Value	10,946	12,238
Variable Interest Entity, Primary Beneficiary [Member] \| Fixed-Maturity Investments [Member]
Amortized cost	134
Fair Value	135
Variable Interest Entity, Primary Beneficiary [Member] \| Fixed-Maturity Investments [Member] \| Asset-Backed Securities [Member]
Amortized cost	134
Fair Value	135
Fixed-Maturity Investments [Member]
Amortized cost	10,014	11,699
Fair Value	9,714	11,115
Fixed-Maturity Investments [Member] \| Mortgage-backed Securities [Member]
Amortized cost	2,002
Fair Value	1,974
Fixed-Maturity Investments [Member] \| Asset-Backed Securities [Member]
Amortized cost	1,086
Fair Value	841
Variable Interest Entity, Primary Beneficiary [Member]
Due in one year or less, Amortized Cost	960
Due in one year or less, Fair Value	962
Due after one year through five years, Amortized Cost	1,086
Due after one year through five years, Fair Value	1,126
Due after five years through ten years, Amortized Cost	1,123
Due after five years through ten years, Fair Value	1,133
Due after ten years through fifteen years, Amortized Cost	777
Due after ten years through fifteen years, Fair Value	779
Due after fifteen years, Amortized Cost	2,980
Due after fifteen years, Fair Value	$ 2,899

Available For Sale Securities, Debt Maturities, Due After Fifteen Years, Amortized Cost

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