Investments (Net Realized Gains (Losses) And Losses Included In Net Realized Gains (Losses) And Other Comprehensive Income) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
OTTI on fixed maturities, gross	$ (67)	$ (13)
OTTI on fixed maturities recognized in OCI (pre-tax)	8	0
OTTI on fixed maturities, net	(59)	(13)
Fixed maturities, Gross realized gains excluding OTTI	65	44
Fixed maturities, Gross realized losses excluding OTTI	(196)	(35)
Total fixed maturities	(190)	(4)
OTTI on equity securities	(1)	0
Equity securities, Gross realized gains excluding OTTI	40	3
Equity securities, Gross realized losses excluding OTTI	(1)	(2)
Total equity securities	38	1
OTTI on other investments	(3)	0
Foreign exchange gains (losses)	39	(31)
Investment and embedded derivative instruments	(39)	1
Fair value adjustments on insurance derivative	(228)	(45)
S&P put options and futures	(15)	(12)
Other derivative instruments	(2)	0
Other	6	1
Total net realized gains (losses) (includes $(152) and $(3) reclassified from AOCI)	$ (394)	$ (89)