Fair Value Measurements (Details 1) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
International program hedging instruments [Member] | Income approach Valuation Technique [Member] | Level 3 [Member] | Equity options [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis	$ 141
Fair value measurements valuation techniques	Option model
Fair value measurements significant assumptions	Equity volatility
Positive or negative relationship of change in input to change in fair value measurement	Increase
International program hedging instruments [Member] | Income approach Valuation Technique [Member] | Level 3 [Member] | Short Interest Rate Swaptions [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis	(26)
Fair value measurements valuation techniques	Option model
Fair value measurements significant assumptions	Interest rate volatility
Positive or negative relationship of change in input to change in fair value measurement	Decrease
Maximum [Member] | International program hedging instruments [Member] | Income approach Valuation Technique [Member] | Level 3 [Member] | Equity options [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Equity Volatility	28.00%
Maximum [Member] | International program hedging instruments [Member] | Income approach Valuation Technique [Member] | Level 3 [Member] | Short Interest Rate Swaptions [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Interest Rate Volatility	25.00%
Minimum [Member] | International program hedging instruments [Member] | Income approach Valuation Technique [Member] | Level 3 [Member] | Equity options [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Equity Volatility	20.00%
Minimum [Member] | International program hedging instruments [Member] | Income approach Valuation Technique [Member] | Level 3 [Member] | Short Interest Rate Swaptions [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Interest Rate Volatility	22.00%
CMBS [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis	1,001
Fair value measurements valuation techniques	Discounted cash flows
Fair value measurements significant assumptions	Spread (encompasses prepayment, default risk and loss severity)
Positive or negative relationship of change in input to change in fair value measurement	Decrease
CMBS [Member] | Maximum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Counterparty Credit Risk	37.71%
CMBS [Member] | Minimum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Counterparty Credit Risk	3.17%
CMBS [Member] | Weighted Average [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Counterparty Credit Risk	10.87%
Corporate [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis	1,204
Fair value measurements valuation techniques	Discounted cash flows
Fair value measurements significant assumptions	Spread
Positive or negative relationship of change in input to change in fair value measurement	Decrease
Corporate [Member] | Maximum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Counterparty Credit Risk	8.00%
Corporate [Member] | Minimum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Counterparty Credit Risk	0.87%
Corporate [Member] | Weighted Average [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Counterparty Credit Risk	3.42%
Equity Derivatives [Member] | Income approach Valuation Technique [Member] | Level 3 [Member] | Equity options [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis	39
Fair value measurements valuation techniques	Option model
Fair value measurements significant assumptions	Equity volatility
Positive or negative relationship of change in input to change in fair value measurement	Increase
Equity Derivatives [Member] | Maximum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member] | Equity options [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Equity Volatility	24.00%
Equity Derivatives [Member] | Minimum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member] | Equity options [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Equity Volatility	13.00%
Interest Rate Derivative [Member] | Income approach Valuation Technique [Member] | Level 3 [Member] | Interest rate swaps [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis	(93)
Fair value measurements valuation techniques	Discounted cash flows
Fair value measurements significant assumptions	Swap curve beyond 30 years volatility
Positive or negative relationship of change in input to change in fair value measurement	Increase
Interest Rate Derivative [Member] | Income approach Valuation Technique [Member] | Level 3 [Member] | Long Interest Rate Swaptions [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis	36
Fair value measurements valuation techniques	Option model
Fair value measurements significant assumptions	Interest rate volatility
Positive or negative relationship of change in input to change in fair value measurement	Increase
Interest Rate Derivative [Member] | Maximum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member] | Interest rate swaps [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Interest Rate Volatility	3.10%
Interest Rate Derivative [Member] | Maximum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member] | Long Interest Rate Swaptions [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Interest Rate Volatility	32.00%
Interest Rate Derivative [Member] | Minimum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member] | Interest rate swaps [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Interest Rate Volatility	3.00%
Interest Rate Derivative [Member] | Minimum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member] | Long Interest Rate Swaptions [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Interest Rate Volatility	25.00%
U.S. GMWB Hedging Instruments [Member] | Equity options [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis	355
Fair value measurements valuation techniques	Option model
Fair value measurements significant assumptions	Equity volatility
Positive or negative relationship of change in input to change in fair value measurement	Increase
U.S. GMWB Hedging Instruments [Member] | Customized swaps [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis	239
Fair value measurements valuation techniques	Discounted cash flows
Fair value measurements significant assumptions	Equity volatility
Positive or negative relationship of change in input to change in fair value measurement	Increase
U.S. GMWB Hedging Instruments [Member] | Maximum [Member] | Equity options [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Equity Volatility	32.00%
U.S. GMWB Hedging Instruments [Member] | Maximum [Member] | Customized swaps [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Equity Volatility	50.00%
U.S. GMWB Hedging Instruments [Member] | Minimum [Member] | Equity options [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Equity Volatility	24.00%
U.S. GMWB Hedging Instruments [Member] | Minimum [Member] | Customized swaps [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Equity Volatility	10.00%
U.S. Macro Hedge Program [Member] | Income approach Valuation Technique [Member] | Level 3 [Member] | Equity options [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis	173
Fair value measurements valuation techniques	Option model
Fair value measurements significant assumptions	Equity volatility
Positive or negative relationship of change in input to change in fair value measurement	Increase
U.S. Macro Hedge Program [Member] | Maximum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member] | Equity options [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Equity Volatility	31.00%
U.S. Macro Hedge Program [Member] | Minimum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member] | Equity options [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Equity Volatility	22.00%
Municipal [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis	625
Fair value measurements valuation techniques	Discounted cash flows
Fair value measurements significant assumptions	Treasury yield beyond 30 years
Positive or negative relationship of change in input to change in fair value measurement	Decrease
Fair Value Inputs [Abstract]
Fair value inputs treasury yield	3.30%
Municipal [Member] | Minimum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair value inputs treasury yield	3.30%
Municipal [Member] | Weighted Average [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair value inputs treasury yield	3.30%
RMBS [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis	$ 1,109
Fair value measurements valuation techniques	Discounted cash flows
RMBS Type 1 [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Fair value measurements significant assumptions	Spread
Positive or negative relationship of change in input to change in fair value measurement	Decrease
RMBS Type 1 [Member] | Maximum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Counterparty Credit Risk	19.76%
RMBS Type 1 [Member] | Minimum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Counterparty Credit Risk	0.60%
RMBS Type 1 [Member] | Weighted Average [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Counterparty Credit Risk	6.91%
RMBS Type 2 [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Fair value measurements significant assumptions	Constant prepayment rate
Positive or negative relationship of change in input to change in fair value measurement	Decrease
RMBS Type 2 [Member] | Maximum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Prepayment Rate	12.00%
RMBS Type 2 [Member] | Minimum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Prepayment Rate	0.00%
RMBS Type 2 [Member] | Weighted Average [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Prepayment Rate	2.00%
RMBS Type 3 [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Fair value measurements significant assumptions	Constant default rate
Positive or negative relationship of change in input to change in fair value measurement	Decrease
RMBS Type 3 [Member] | Maximum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Probability of Default	28.00%
RMBS Type 3 [Member] | Minimum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Probability of Default	1.00%
RMBS Type 3 [Member] | Weighted Average [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Probability of Default	8.00%
RMBS Type 4 [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Fair value measurements significant assumptions	Loss severity
Positive or negative relationship of change in input to change in fair value measurement	Decrease
RMBS Type 4 [Member] | Maximum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Loss Severity	100.00%
RMBS Type 4 [Member] | Minimum [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Loss Severity	45.00%
RMBS Type 4 [Member] | Weighted Average [Member] | Income approach Valuation Technique [Member] | Level 3 [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs Loss Severity	75.00%