Investments (Details 23) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	$ 91	$ 123	$ 224	$ 246
Fixed maturity securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	91	123	224	246
Communications Domestic Corporate Debt Securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	1	1	18	14
Consumer Domestic Corporate Debt Securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	9	27	12	29
Utility Domestic Corporate Debt Securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	13	0	51	1
Industrial Domestic Corporate Debt Securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	0	0	1	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	40	32	41
Corporate fixed maturity securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	29	68	120	85
Foreign government debt securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	0	13	0	89
RMBS [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	37	42	46	66
ABS [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	5	0	7	3
CMBS [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	20	0	50	3
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
Other fixed maturity securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	$ 6	$ 0	$ 6	$ 0