Investments and Derivative Instruments (Details 17) (Fair value hedges [Member], USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
Derivative Instruments Gain (Loss) [Line Items]
Gain or (Loss) Recognized in Income, Derivative	$ (22)	[1]	$ (6)	[1]	$ (5)	[1]	$ 10	[1]
Gain or (Loss) Recognized in Income, Hedged Item	19	[1]	5	[1]	3	[1]	(10)	[1]
Interest Rate Swap [Member] | Net realized capital gains (losses) [Member]
Derivative Instruments Gain (Loss) [Line Items]
Gain or (Loss) Recognized in Income, Derivative	(16)	[1]	(27)	[1]	(5)	[1]	(17)	[1]
Gain or (Loss) Recognized in Income, Hedged Item	13	[1]	26	[1]	3	[1]	17	[1]
Foreign Currency Swap [Member] | Net realized capital gains (losses) [Member]
Derivative Instruments Gain (Loss) [Line Items]
Gain or (Loss) Recognized in Income, Derivative	(11)	[1]	22	[1]	(2)	[1]	36	[1]
Gain or (Loss) Recognized in Income, Hedged Item	11	[1]	(22)	[1]	2	[1]	(36)	[1]
Foreign Currency Swap [Member] | Benefits, losses and loss adjustment expenses [Member]
Derivative Instruments Gain (Loss) [Line Items]
Gain or (Loss) Recognized in Income, Derivative	5	[1]	(1)	[1]	2	[1]	(9)	[1]
Gain or (Loss) Recognized in Income, Hedged Item	$ (5)	[1]	$ 1	[1]	$ (2)	[1]	$ 9	[1]

[1] The amounts presented do not include the periodic net coupon settlements of the derivative or the coupon income (expense) related to the hedged item. The net of the amounts presented represents the ineffective portion of the hedge.