Investments (Details 3) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Net Investment Income:
Investment income, before expense	$ 1,065	$ 1,094	$ 2,096	$ 2,187
Investment expense	(45)	(45)	(94)	(88)
Net investment income	1,020	1,049	2,002	2,099
Fixed income securities
Net Investment Income:
Investment income, before expense	899	955	1,799	1,914
Equity securities
Net Investment Income:
Investment income, before expense	34	25	53	46
Mortgage loans
Net Investment Income:
Investment income, before expense	87	99	176	203
Limited partnership interests
Net Investment Income:
Investment income, before expense	18	7	28	13
Short-term investments
Net Investment Income:
Investment income, before expense	1	2	3	4
Other:
Net Investment Income:
Investment income, before expense	$ 26	$ 6	$ 37	$ 7