Investments (Details 23) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	$ 133	$ 123
Fixed maturity securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	133	123
Communications Domestic Corporate Debt Securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	17	13
Consumer Domestic Corporate Debt Securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	3	2
Utility Domestic Corporate Debt Securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	38	1
Industrial Domestic Corporate Debt Securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	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	32	1
Corporate fixed maturity securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	91	17
Foreign government debt securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	0	76
RMBS [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	9	24
ABS [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	2	3
CMBS [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	30	3
State and political subdivision securities [Member]
Entity Sector Industry Classifications [Abstract]
Fixed maturity securities other than temporary impairment losses recognized in earnings, net	$ 1	$ 0