Investments (Net Realized Gains (Losses) And Losses Included In Net Realized Gains (Losses) And Other Comprehensive Income) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Investments, Debt and Equity Securities [Abstract]
OTTI on fixed maturities, gross									$ (18)	$ (26)	$ (61)
OTTI on fixed maturities recognized in OCI (pre-tax)									0	1	15
OTTI on fixed maturities, net									(18)	(25)	(46)
Fixed maturities, Gross realized gains excluding OTTI									237	388	410
Fixed maturities, Gross realized losses excluding OTTI									(129)	(133)	(200)
Total fixed maturities									90	230	164
OTTI on equity securities									(2)	(5)	(1)
Equity securities, Gross realized gains excluding OTTI									21	11	15
Equity securities, Gross realized losses excluding OTTI									(4)	(2)	(5)
Total equity securities									15	4	9
OTTI on other investments									(2)	(7)	(3)
Foreign exchange losses									29	(16)	(13)
Investment and embedded derivative instruments									78	(6)	(143)
Fair value adjustments on insurance derivative									878	171	(779)
S&P put options and futures									(579)	(297)	(4)
Other derivative instruments									(2)	(4)	(4)
Other									(3)	3	(22)
Total net realized gains (losses)	154	40	104	206	272	(60)	(394)	260	504	78	(795)
Change in net unrealized appreciation (depreciation) on investments, Fixed maturities available for sale									(1,798)	1,099	569
Change in net unrealized appreciation (depreciation) on investments, Fixed maturities held to maturity									(82)	(94)	(89)
Change in net unrealized appreciation (depreciation) on investments, Equity securities									(41)	61	(47)
Change in net unrealized appreciation (depreciation) on investments, Other									54	50	40
Change in net unrealized appreciation (depreciation) on investments, Income tax expense									408	(198)	(157)
Change in net unrealized appreciation on investments,									(1,459)	918	316
Total net realized gains (losses) and change in net unrealized appreciation (depreciation) on investments									$ (955)	$ 996	$ (479)