Investments (Details 23) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	$ 47	$ 284	$ 271	$ 530
Fixed maturity securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	47	284	271	530
Communications Domestic Corporate Debt Securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	1	12	19	26
Consumer Domestic Corporate Debt Securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	4	6	16	35
Utility Domestic Corporate Debt Securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	10	6	61	7
Industrial Domestic Corporate Debt Securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	4	0	5	0
Finance Domestic Corporate Debt Securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	0	7	32	48
Transportation [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	11	0	17	0
Corporate fixed maturity securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	30	31	150	116
Foreign government debt securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	0	206	0	295
RMBS [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	15	34	61	100
ABS [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	2	8	9	11
CMBS [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	0	5	50	8
State and political subdivision securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	$ 0	$ 0	$ 1	$ 0