Reinsurance - Earned Life Insurance Premiums on Ceded Business (Detail) - Life Insurance Segment - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Direct earned premiums	$ 67	$ 61	$ 200	$ 191
Ceded earned premiums	(16)	(15)	(44)	(44)
Earned premiums	$ 51	$ 46	$ 156	$ 147