Fair Value Measurements - Financial Instruments Excluding Guaranteed Living Benefits (Details 3) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value of assets accounted for using fair value option	$ 1,323	$ 649
Fixed Maturities, FVO [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value of assets accounted for using fair value option
ABS [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value of assets accounted for using fair value option	65	65
CDOs [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value of assets accounted for using fair value option	225	270
Corporate [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value of assets accounted for using fair value option	268	250
Foreign government/government agencies [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value of assets accounted for using fair value option	765	64
Credit-linked notes [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value of liabilities accounted for using fair value option	$ 13	$ 37