Invested Assets - Realized Investment Gains and Losses (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Investments, Debt and Equity Securities [Abstract]
Fixed maturities, Gross realized gains	$ 27	$ 17	$ 104	$ 44
Fixed maturities, Gross realized losses	(5)	(22)	(33)	(32)
Fixed maturities, Other-than-temporary impairment losses		(2)	(4)	(2)
Total fixed maturities	22	(7)	67	10
Equity securities, Gross realized gains	43	5	132	179
Equity securities, Gross realized losses		(1)		(1)
Equity securities, Other-than-temporary impairment losses		(2)	(1)	(9)
Total equity securities	43	2	131	169
Other invested assets	45	23	153	156
Total Realized Investment Gains, Net	$ 110	$ 18	$ 351	$ 335