Investments and Cash (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended				3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended				9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Fixed and short-term maturity securities	Dec. 31, 2012 Fixed and short-term maturity securities	Sep. 30, 2013 Fixed maturity securities	Sep. 30, 2012 Fixed maturity securities	Sep. 30, 2013 Fixed maturity securities	Sep. 30, 2012 Fixed maturity securities	Sep. 30, 2013 Fixed maturity securities purchased or obtained for loss mitigation purposes	Sep. 30, 2012 Fixed maturity securities purchased or obtained for loss mitigation purposes	Sep. 30, 2013 Fixed maturity securities purchased or obtained for loss mitigation purposes	Sep. 30, 2012 Fixed maturity securities purchased or obtained for loss mitigation purposes	Sep. 30, 2013 Other invested assests		Sep. 30, 2012 Other invested assests		Sep. 30, 2013 Other invested assests		Sep. 30, 2012 Other invested assests
Investments
Accrued investment income					$ 96	$ 97
Net Investment Income
Gross investment income	101	104	292	308			81	87	241	262	19	15	47	42	1	[1]	2	[1]	4	[1]	4	[1]
Investment expenses	(2)	(2)	(6)	(7)
Net investment income	99	102	286	301
Net Realized Investment Gains (Losses)
Realized gains on investment portfolio	6	8	61	34
Realized losses on investment portfolio	(5)	(2)	(18)	(23)
Other than Temporary Impairment Losses, Investments	(8)	(4)	(20)	(11)
Other-than-temporary impairment (OTTI):
Net realized investment gains (losses)	(7)	2	23	0
Roll Forward of Credit Losses in the Investment Portfolio
Balance, at the beginning of the period	72	53	64	47
Additions for credit losses on securities for which an OTTI was not previously recognized	1	1	2	8
Reductions for securities sold during the period	0	(3)	0	(4)
Additions for credit losses on securities for which an OTTI was previously recognized	6	3	13	3
Balance, at the end of the period	$ 79	$ 54	$ 79	$ 54

[1] Includes income from short-term investments and assets acquired in refinancing transactions.