Investments (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net investment income
Investment income, before expense	$ 648	$ 650	$ 1,945	$ 2,031
Investment expense	(27)	(29)	(84)	(87)
Net investment income	621	621	1,861	1,944
Fixed income securities
Net investment income
Investment income, before expense	487	521	1,477	1,567
Mortgage loans
Net investment income
Investment income, before expense	91	86	269	256
Equity securities
Net investment income
Investment income, before expense	3	2	8	5
Limited partnership interests
Net investment income
Investment income, before expense	37	11	104	117
Short-term investments
Net investment income
Investment income, before expense		1	1	1
Policy loans
Net investment income
Investment income, before expense	12	13	36	39
Other
Net investment income
Investment income, before expense	$ 18	$ 16	$ 50	$ 46