Investments (Details 4) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Realized capital gains and losses by asset type
Realized capital gains and losses	$ 33	$ 294	$ 280	$ 588
Fixed income securities
Realized capital gains and losses by asset type
Realized capital gains and losses	221	23	361	121
Equity securities
Realized capital gains and losses by asset type
Realized capital gains and losses	(150)	213	(24)	474
Mortgage loans
Realized capital gains and losses by asset type
Realized capital gains and losses	1	2	2	3
Limited partnership interests
Realized capital gains and losses by asset type
Realized capital gains and losses	(55)	59	(52)	10
Derivatives
Realized capital gains and losses by asset type
Realized capital gains and losses	24	(8)	4	(27)
Other
Realized capital gains and losses by asset type
Realized capital gains and losses	$ (8)	$ 5	$ (11)	$ 7