Derivatives (Details 1) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Summary of gain (loss) included in earnings for changes in the fair value of derivatives
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ (15)	$ (36)	$ (37)	$ (58)
MBS with embedded derivatives [Member] | Realized gains [Member]
Summary of gain (loss) included in earnings for changes in the fair value of derivatives
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	1	3	4	0
Interest rate swaptions [Member] | Realized gains [Member]
Summary of gain (loss) included in earnings for changes in the fair value of derivatives
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(1)	(15)	(4)	(22)
Fixed-indexed annuities (embedded derivative) [Member] | Annuity benefits [Member]
Summary of gain (loss) included in earnings for changes in the fair value of derivatives
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(41)	32	(97)	4
Equity index call options [Member] | Annuity benefits [Member]
Summary of gain (loss) included in earnings for changes in the fair value of derivatives
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	30	(50)	67	(30)
Reinsurance contracts (embedded derivative) [Member] | Investment Income [Member]
Summary of gain (loss) included in earnings for changes in the fair value of derivatives
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ (4)	$ (6)	$ (7)	$ (10)