Reinsurance - Earned Life Insurance Premiums on Ceded Business (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
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Direct earned premiums	$ 1,002	$ 898	$ 2,895	$ 2,605
Assumed earned premiums	3	1	8	7
Ceded earned premiums	(51)	(48)	(150)	(137)
Life Insurance Segment
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Direct earned premiums	52	52	166	170
Assumed earned premiums	0	0	0	0
Ceded earned premiums	(14)	(14)	(42)	(40)
Net earned premiums	$ 38	$ 38	$ 124	$ 130