Investments and Cash - Net Investment Income, Net Realized Investment Gains (Losses) and Roll Forward of Credit Losses in the Investment Portfolio (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, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Fixed Maturities managed externally	Sep. 30, 2013 Fixed Maturities managed externally	Sep. 30, 2014 Fixed Maturities managed externally	Sep. 30, 2013 Fixed Maturities managed externally	Sep. 30, 2014 Fixed and short-term maturity securities	Dec. 31, 2013 Fixed and short-term maturity securities	Sep. 30, 2014 Fixed Maturities managed internally	Sep. 30, 2013 Fixed Maturities managed internally	Sep. 30, 2014 Fixed Maturities managed internally	Sep. 30, 2013 Fixed Maturities managed internally	Sep. 30, 2014 Other Invested Assets internally managed	Sep. 30, 2013 Other Invested Assets internally managed	Sep. 30, 2014 Other Invested Assets internally managed	Sep. 30, 2013 Other Invested Assets internally managed
Investments
Accrued investment income									$ 97	$ 93
Net Investment Income
Gross investment income	104	101	307	292	83	80	244	239			15	19	52	49	6	2	11	4
Investment expenses	(2)	(2)	(6)	(6)
Net investment income	102	99	301	286
Net Realized Investment Gains (Losses)
Gross realized gains on available-for-sale securities	3	5	10	23
Gross realized gains on other assets in investment portfolio	1	2	8	38
Gross realized losses on available-for-sale securities	(1)	(2)	(4)	(11)
Gross realized losses on other assets in investment portfolio	(1)	(4)	(1)	(7)
Other-than-temporary impairment	(21)	(8)	(38)	(20)
Net realized investment gains (losses)	(19)	(7)	(25)	23
Roll Forward of Credit Losses in the Investment Portfolio
Balance, at the beginning of the period	84	72	80	64
Additions for credit losses on securities for which an other-than-temporary-impairment was not previously recognized	3	1	29	2
Reductions for securities sold during the period	0	0	(12)	0
Additions for credit losses on securities for which an other-than-temporary-impairment was previously recognized	17	6	7	13
Balance, at the end of the period	$ 104	$ 79	$ 104	$ 79