Deferred Acquisition Costs - Deferred Policy Acquisition Costs and Asset Reconciliation (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs asset at beginning of period	$ 546	$ 484	$ 470	$ 477
Capitalized deferred policy acquisition costs	211	192	612	554
Amortized deferred policy acquisition costs	(190)	(180)	(552)	(517)
Amortized shadow deferred policy acquisition costs	9	(5)	46	(23)
Deferred policy acquisition costs asset at end of period	$ 576	$ 491	$ 576	$ 491