Investments (Net Realized Gains (Losses) And The Losses Included In Net Realized Gains (Losses) And OCI) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Investments [Abstract]
OTTI on fixed maturities, gross									$ (61)	$ (115)	$ (536)
OTTI on fixed maturities recognized in OCI (pre-tax)									15	69	302
OTTI on fixed maturities, net									(46)	(46)	(234)
Fixed maturities, Gross realized gains excluding OTTI									410	569	591
Fixed maturities, Gross realized losses excluding OTTI									(200)	(143)	(398)
Total fixed maturities									164	380	(41)
OTTI on equity securities									(1)		(26)
Equity securities, Gross realized gains excluding OTTI									15	86	105
Equity securities, Gross realized losses excluding OTTI									(5)	(2)	(224)
Total equity securities									9	84	(145)
OTTI on other investments									(3)	(13)	(137)
Foreign exchange losses									(13)	(54)	(21)
Investment and embedded derivative instruments									(143)	58	68
Fair value adjustments on insurance derivative									(779)	(28)	368
S&P put options and futures									(4)	(150)	(363)
Other derivative instruments									(4)	(19)	(93)
Other									(22)	174	168
Total net realized gains (losses)	83	(760)	(73)	(45)	305	(50)	9	168	(795)	432	(196)
Change in net unrealized appreciation (depreciation) on investments, Fixed maturities available for sale									569	451	2,723
Change in net unrealized appreciation (depreciation) on investments, Fixed maturities held to maturity									(89)	522	(6)
Change in net unrealized appreciation (depreciation) on investments, Equity securities									(47)	(44)	213
Change in net unrealized appreciation (depreciation) on investments, Other									40	(35)	162
Change in net unrealized appreciation (depreciation) on investments, Income tax expense									(157)	(152)	(481)
Change in net unrealized appreciation on investments									316	742	2,611
Total net realized gains (losses) and change in net unrealized appreciation (depreciation) on investments									$ (479)	$ 1,174	$ 2,415