Earned Life Insurance Premiums on Ceded Business (Detail) (Life Insurance Segment, USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Life Insurance Segment
Reinsurance [Line Items]
Direct earned premiums	$ 64	$ 55	$ 118	$ 105
Assumed earned premiums
Ceded earned premiums	(13)	(12)	(26)	(25)
Net earned premiums	$ 51	$ 43	$ 92	$ 80