Investments- Net Ivestment Income (Details 3) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Net investment income
Investment income, before expense	$ 486	$ 480	$ 1,459	$ 1,667
Investment expense	(13)	(19)	(42)	(55)
Net investment income	473	461	1,417	1,612
Fixed income securities
Net investment income
Investment income, before expense	300	349	960	1,179
Mortgage loans
Net investment income
Investment income, before expense	46	48	147	188
Equity securities
Net investment income
Investment income, before expense	6	7	19	17
Limited partnership interests
Net investment income
Investment income, before expense	105	51	250	209
Short-term investments
Net investment income
Investment income, before expense	1	0	2	1
Policy loans
Net investment income
Investment income, before expense	9	10	26	30
Other
Net investment income
Investment income, before expense	$ 19	$ 15	$ 55	$ 43