Investments and Cash (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended				3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended				6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Fixed and Short-term Maturities [Member]	Dec. 31, 2012 Fixed and Short-term Maturities [Member]	Jun. 30, 2013 Fixed maturity securities	Jun. 30, 2012 Fixed maturity securities	Jun. 30, 2013 Fixed maturity securities	Jun. 30, 2012 Fixed maturity securities	Jun. 30, 2013 Fixed Maturity Securities purchased or obtained for loss mitigation purposes [Member]	Jun. 30, 2012 Fixed Maturity Securities purchased or obtained for loss mitigation purposes [Member]	Jun. 30, 2013 Fixed Maturity Securities purchased or obtained for loss mitigation purposes [Member]	Jun. 30, 2012 Fixed Maturity Securities purchased or obtained for loss mitigation purposes [Member]	Jun. 30, 2013 Other invested assests [Member]		Jun. 30, 2012 Other invested assests [Member]		Jun. 30, 2013 Other invested assests [Member]		Jun. 30, 2012 Other invested assests [Member]
Investments
Accrued investment income					$ 94	$ 97
Net Investment Income
Gross investment income	95	104	191	204			81	88	160	175	12	15	28	27	2	[1]	1	[1]	3	[1]	2	[1]
Investment expenses	(2)	(3)	(4)	(5)
Net investment income	93	101	187	199
Net Realized Investment Gains (Losses)
Realized gains on investment portfolio	16	17	55	26
Realized losses on investment portfolio	(7)	(18)	(13)	(21)
Other than Temporary Impairment Losses, Investments	(7)	(2)	(12)	(7)
Other-than-temporary impairment (OTTI):
Net realized investment gains (losses)	2	(3)	30	(2)
Roll Forward of Credit Losses in the Investment Portfolio
Balance, at the beginning of the period	69	51	64	47
Additions for credit losses on securities for which an OTTI was not previously recognized	0	0	1	2
Additions for credit losses on securities for which an OTTI was previously recognized	3	2	7	4
Balance, at the end of the period	$ 72	$ 53	$ 72	$ 53

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