Fair Value Measurements (Details 1) (Income approach Valuation Technique [Member], Level 3 [Member], USD $) In Millions, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2013		Dec. 31, 2012
International program 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	$ (43)		$ 26
Fair value measurements valuation techniques	Option model		Option model
Fair value measurements significant assumptions	Equity volatility		Equity volatility
Positive or negative relationship of change in input to change in fair value measurement	Increase	[1]	Increase	[1]
International program hedging instruments [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			42
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	[1]
CMBS [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis	818		859
Fair value measurements valuation techniques	Discounted cash flows		Discounted cash flows
Fair value measurements significant assumptions	Spread (encompasses prepayment, default risk and loss severity)		Spread (encompasses prepayment, default risk and loss severity)
Positive or negative relationship of change in input to change in fair value measurement	Decrease	[2]	Decrease	[2]
CMBS [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Counterparty Credit Risk	33.02%		36.15%
CMBS [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Counterparty Credit Risk	0.60%		3.20%
CMBS [Member] | Weighted Average [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Counterparty Credit Risk	8.26%		10.31%
Corporate [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis	683	[3]	1,371	[3]
Fair value measurements valuation techniques	Discounted cash flows	[3]	Discounted cash flows	[3]
Fair value measurements significant assumptions	Spread	[3]	Spread	[3]
Positive or negative relationship of change in input to change in fair value measurement	Decrease	[2],[3]	Decrease	[2],[3]
Corporate [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Counterparty Credit Risk	47.00%		9.00%
Corporate [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Counterparty Credit Risk	1.80%		1.06%
Corporate [Member] | Weighted Average [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Counterparty Credit Risk	4.22%		3.28%
Equity Derivatives [Member] | Equity options [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis			57
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	[1]
Interest Rate Derivative [Member] | Interest Rate Swap [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis	(51)		(55)
Fair value measurements valuation techniques	Discounted cash flows		Discounted cash flows
Fair value measurements significant assumptions	Swap curve beyond 30 years		Swap curve beyond 30 years
Positive or negative relationship of change in input to change in fair value measurement	Increase	[1]	Increase	[1]
Interest Rate Derivative [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		23
Fair value measurements valuation techniques	Option model		Option model
Fair value measurements significant assumptions	Interest rate volatility		Interest rate volatility
Positive or negative relationship of change in input to change in fair value measurement	Increase	[1]	Increase	[1]
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	180		281
Fair value measurements valuation techniques	Option model		Option model
Fair value measurements significant assumptions	Equity volatility		Equity volatility
Positive or negative relationship of change in input to change in fair value measurement	Increase	[1]	Increase	[1]
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	149		238
Fair value measurements valuation techniques	Discounted cash flows		Discounted cash flows
Fair value measurements significant assumptions	Equity volatility		Equity volatility
Positive or negative relationship of change in input to change in fair value measurement	Increase	[1]	Increase	[1]
U.S. Macro Hedge Program [Member] | Equity options [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis	209		286
Fair value measurements valuation techniques	Option model		Option model
Fair value measurements significant assumptions	Equity volatility		Equity volatility
Positive or negative relationship of change in input to change in fair value measurement	Increase	[1]	Increase	[1]
Municipal [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis	127		227
Fair value measurements valuation techniques	Discounted cash flows		Discounted cash flows
Fair value measurements significant assumptions	Spread		Spread
Positive or negative relationship of change in input to change in fair value measurement	Decrease	[2]	Decrease	[2]
Municipal [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Fair value inputs treasury yield	2.93%		3.44%
Municipal [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Fair value inputs treasury yield	2.31%		2.27%
Municipal [Member] | Weighted Average [Member]
Fair Value Inputs [Abstract]
Fair value inputs treasury yield	2.50%		2.58%
RMBS [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Assets accounted for at Fair Value on a recurring basis	$ 1,352		$ 1,373
Fair value measurements valuation techniques	Discounted cash flows		Discounted cash flows
RMBS Type 1 [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Fair value measurements significant assumptions	Spread		Spread
Positive or negative relationship of change in input to change in fair value measurement	Decrease	[2]	Decrease	[2]
RMBS Type 1 [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Counterparty Credit Risk	19.81%		16.89%
RMBS Type 1 [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Counterparty Credit Risk	0.56%		0.54%
RMBS Type 1 [Member] | Weighted Average [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Counterparty Credit Risk	2.68%		3.67%
RMBS Type 2 [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Fair value measurements significant assumptions	Constant prepayment rate		Constant prepayment rate
Positive or negative relationship of change in input to change in fair value measurement	Decrease [4]	[2],[4]	Decrease [4]	[2],[4]
RMBS Type 3 [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Fair value measurements significant assumptions	Constant default rate		Constant default rate
Positive or negative relationship of change in input to change in fair value measurement	Decrease	[2]	Decrease	[2]
RMBS Type 4 [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Abstract]
Fair value measurements significant assumptions	Loss severity		Loss severity
Positive or negative relationship of change in input to change in fair value measurement	Decrease	[2]	Decrease	[2]

[1] Conversely, the impact of a decrease in input would have the opposite impact to the fair value as that presented in the table. Changes are based on long positions, unless otherwise noted. Changes in fair value will be inversely impacted for short positions.

[2] Conversely, the impact of a decrease in input would have the opposite impact to the fair value as that presented in the table above.

[3] Level 3 corporate securities excludes those for which the Company bases fair value on broker quotations as discussed below.

[4] Decrease for above market rate coupons and increase for below market rate coupons.5. Fair Value Measurements (continued) As of June 30, 2013Freestanding DerivativesUnobservable Inputs FairValuePredominantValuation MethodSignificant Unobservable InputMinimumMaximumImpact of Increase in Input on Fair Value [1]Interest rate derivative Interest rate swaps(51)Discountedcash flowsSwap curve beyond 30 years3.4%3.4%IncreaseLong interest rate swaptions36Option modelInterest rate volatility1%1%IncreaseU.S. GMWB hedging instruments Equity options180Option modelEquity volatility22%34%IncreaseCustomized swaps149Discountedcash flowsEquity volatility10%50%IncreaseU.S. macro hedge program Equity options209Option modelEquity volatility25%33%IncreaseInternational program hedging Equity options(43)Option modelEquity volatility22%50%Increase As of December 31, 2012 Equity derivatives Equity options57Option modelEquity volatility13%24%IncreaseInterest rate derivative Interest rate swaps(55)Discountedcash flowsSwap curve beyond 30 years2.8%2.8%IncreaseLong interest rate swaptions23Option modelInterest rate volatility—%1%IncreaseU.S. GMWB hedging instruments Equity options281Option modelEquity volatility10%31%IncreaseCustomized swaps238Discountedcash flowsEquity volatility10%50%IncreaseU.S. macro hedge program Equity options286Option modelEquity volatility24%43%IncreaseInternational program hedging Equity options26Option modelEquity volatility19%27%IncreaseLong interest rate swaptions42Option modelInterest rate volatility—%1%Increase