Fair Value Measurements - Financial Instruments Excluding Guaranteed Living Benefits (Details) (Textuals) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Credit standing adjustment assumption net of reinsurance [Member]
Fair Value, Financial Instruments Related To Guaranteed Living Benefits Program Measured on Recurring Basis [Line Items]
Pre-tax realized gains	$ 1	$ 54
Outperformance (underperformance) of the underlying actively managed fund compared to indices [Member]
Fair Value, Financial Instruments Related To Guaranteed Living Benefits Program Measured on Recurring Basis [Line Items]
Pre-tax realized gains	$ 4	$ 15	$ 29	$ 42