Investments (Details 3) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Net Investment Income:
Investment income, before expense	$ 842	$ 867	$ 2,557	$ 2,798
Investment expense	(35)	(44)	(111)	(118)
Net investment income	807	823	2,446	2,680
Fixed income securities
Net Investment Income:
Investment income, before expense	546	581	1,681	1,870
Equity securities
Net Investment Income:
Investment income, before expense	23	28	77	91
Mortgage loans
Net Investment Income:
Investment income, before expense	53	54	165	206
Limited partnership interests
Net Investment Income:
Investment income, before expense	167	162	483	499
Short-term investments
Net Investment Income:
Investment income, before expense	4	1	8	5
Other
Net Investment Income:
Investment income, before expense	$ 49	$ 41	$ 143	$ 127