Earned Life Insurance Premiums on Ceded Business (Detail) (Life Insurance Segment, USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Life Insurance Segment
Reinsurance [Line Items]
Direct earned premiums	$ 52	$ 57	$ 170	$ 162
Assumed earned premiums
Ceded earned premiums	(14)	(14)	(40)	(39)
Net earned premiums	$ 38	$ 43	$ 130	$ 123