Investments (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Net investment income
Investment income, before expense	$ 649	$ 680	$ 1,297	$ 1,381
Investment expense	(30)	(30)	(57)	(58)
Net investment income	619	650	1,240	1,323
Fixed income securities
Net investment income
Investment income, before expense	494	525	990	1,046
Mortgage loans
Net investment income
Investment income, before expense	87	85	178	170
Equity securities
Net investment income
Investment income, before expense	3	2	5	3
Limited partnership interests
Net investment income
Investment income, before expense	37	39	67	106
Short-term investments
Net investment income
Investment income, before expense			1
Policy loans
Net investment income
Investment income, before expense	12	13	24	26
Other
Net investment income
Investment income, before expense	$ 16	$ 16	$ 32	$ 30