Investments- Realized Capital Gains and Losses (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	$ 189	$ 28	$ 359	$ 18
Fixed income securities
Realized capital gains and losses by asset type
Realized capital gains and losses	256	(1)	370	(1)
Mortgage loans
Realized capital gains and losses by asset type
Realized capital gains and losses	1	2	2	3
Equity securities
Realized capital gains and losses by asset type
Realized capital gains and losses	(58)	(5)	(10)	11
Limited partnership interests
Realized capital gains and losses by asset type
Realized capital gains and losses	(20)	28	(18)	(5)
Derivatives
Realized capital gains and losses by asset type
Realized capital gains and losses	15	4	21	7
Other
Realized capital gains and losses by asset type
Realized capital gains and losses	$ (5)	$ 0	$ (6)	$ 3