Investments (Details 3) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Net Investment Income:
Investment income, before expense	$ 1,038	$ 1,048	$ 3,134	$ 3,235
Investment expense	(44)	(43)	(138)	(131)
Net investment income	994	1,005	2,996	3,104
Fixed income securities
Net Investment Income:
Investment income, before expense	862	926	2,661	2,840
Equity securities
Net Investment Income:
Investment income, before expense	23	17	76	63
Mortgage loans
Net Investment Income:
Investment income, before expense	91	92	267	295
Limited partnership interests
Net Investment Income:
Investment income, before expense	33	6	61	19
Short-term investments
Net Investment Income:
Investment income, before expense	2	2	5	6
Other:
Net Investment Income:
Investment income, before expense	$ 27	$ 5	$ 64	$ 12