Investments (Distribution Of Contractual Maturity Available For Sale) (Details) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 10,754	$ 12,822
Fair Value	10,562	12,238
Variable Interest Entity, Primary Beneficiary [Member] \| Fixed-Maturity Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Due after one year through five years, Amortized Cost	2
Due after one year through five years, Fair Value	2
Amortized cost	356
Fair Value	314
Variable Interest Entity, Primary Beneficiary [Member] \| Fixed-Maturity Investments [Member] \| Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	124
Fair Value	96
Variable Interest Entity, Primary Beneficiary [Member] \| Fixed-Maturity Investments [Member] \| Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	230
Fair Value	216
Fixed-Maturity Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Due in one year or less, Amortized Cost	721
Due in one year or less, Fair Value	723
Due after one year through five years, Amortized Cost	1,147
Due after one year through five years, Fair Value	1,170
Due after five years through ten years, Amortized Cost	1,014
Due after five years through ten years, Fair Value	1,052
Due after ten years through fifteen years, Amortized Cost	826
Due after ten years through fifteen years, Fair Value	846
Due after fifteen years, Amortized Cost	2,941
Due after fifteen years, Fair Value	2,998
Amortized cost	9,287	11,699
Fair Value	9,166	11,115
Fixed-Maturity Investments [Member] \| Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	1,772
Fair Value	1,780
Fixed-Maturity Investments [Member] \| Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	866
Fair Value	$ 597

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

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