Investments- Net Ivestment Income (Details 3) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Net investment income
Investment income, before expense	$ 486	$ 541	$ 973	$ 1,187
Investment expense	(13)	(16)	(29)	(36)
Net investment income	473	525	944	1,151
Fixed income securities
Net investment income
Investment income, before expense	326	356	660	830
Mortgage loans
Net investment income
Investment income, before expense	52	65	101	140
Equity securities
Net investment income
Investment income, before expense	8	6	13	10
Limited partnership interests
Net investment income
Investment income, before expense	73	91	145	158
Short-term investments
Net investment income
Investment income, before expense	1	1	1	1
Policy loans
Net investment income
Investment income, before expense	8	9	17	20
Other
Net investment income
Investment income, before expense	$ 18	$ 13	$ 36	$ 28