Investments (Net Realized Gains (Losses) And Losses Included In Net Realized Gains (Losses) And Other Comprehensive Income) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Investments, Debt and Equity Securities [Abstract]
OTTI on fixed maturities, gross	$ (11)	$ (13)	$ (78)	$ (26)
OTTI on fixed maturities recognized in OCI (pre-tax)	0	6	8	6
OTTI on fixed maturities, net	(11)	(7)	(70)	(20)
Fixed maturities, Gross realized gains excluding OTTI	37	28	102	72
Fixed maturities, Gross realized losses excluding OTTI	(19)	(16)	(215)	(51)
Total fixed maturities	7	5	(183)	1
OTTI on equity securities	(5)	(1)	(6)	(1)
Equity securities, Gross realized gains excluding OTTI	4	30	44	33
Equity securities, Gross realized losses excluding OTTI	(4)	0	(5)	(2)
Total equity securities	(5)	29	33	30
OTTI on other investments	0	0	(3)	0
Foreign exchange gains (losses)	(22)	(40)	17	(71)
Investment and embedded derivative instruments	(47)	27	(86)	28
Fair value adjustments on insurance derivative	(131)	104	(359)	59
S&P put options and futures	(28)	(2)	(43)	(14)
Other derivative instruments	0	(1)	(2)	(1)
Other	10	4	16	5
Total net realized gains (losses) (includes $2, $34, $(150), and $31 reclassified from AOCI)	$ (216)	$ 126	$ (610)	$ 37