Investments (Details 3) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Net Investment Income:
Investment income, before expense	$ 825	$ 932	$ 1,715	$ 1,931
Investment expense	(36)	(34)	(76)	(74)
Net investment income	789	898	1,639	1,857
Fixed income securities
Net Investment Income:
Investment income, before expense	567	584	1,135	1,289
Equity securities
Net Investment Income:
Investment income, before expense	31	35	54	63
Mortgage loans
Net Investment Income:
Investment income, before expense	57	71	112	152
Limited partnership interests
Net Investment Income:
Investment income, before expense	118	195	316	337
Short-term investments
Net Investment Income:
Investment income, before expense	3	3	4	4
Other
Net Investment Income:
Investment income, before expense	$ 49	$ 44	$ 94	$ 86