Investments- Realized Capital Gains and Losses (Details 4) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Realized capital gains and losses by asset type
Realized capital gains and losses	$ (19)	$ 189	$ (66)	$ 359
Fixed income securities
Realized capital gains and losses by asset type
Realized capital gains and losses	(17)	256	(42)	370
Mortgage loans
Realized capital gains and losses by asset type
Realized capital gains and losses	0	1	1	2
Equity securities
Realized capital gains and losses by asset type
Realized capital gains and losses	3	(58)	(31)	(10)
Limited partnership interests
Realized capital gains and losses by asset type
Realized capital gains and losses	(1)	(20)	12	(18)
Derivatives
Realized capital gains and losses by asset type
Realized capital gains and losses	(1)	15	(2)	21
Other
Realized capital gains and losses by asset type
Realized capital gains and losses	$ (3)	$ (5)	$ (4)	$ (6)