Investments (Details 4) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Realized capital gains and losses by asset type
Realized capital gains and losses	$ 24	$ 108	$ (125)	$ 247
Fixed income securities
Realized capital gains and losses by asset type
Realized capital gains and losses	24	60	(47)	140
Equity securities
Realized capital gains and losses by asset type
Realized capital gains and losses	11	48	(79)	126
Mortgage loans
Realized capital gains and losses by asset type
Realized capital gains and losses	1	1	1	1
Limited partnership interests
Realized capital gains and losses by asset type
Realized capital gains and losses	(13)	(3)	13	3
Derivatives
Realized capital gains and losses by asset type
Realized capital gains and losses	2	5	(7)	(20)
Other
Realized capital gains and losses by asset type
Realized capital gains and losses	$ (1)	$ (3)	$ (6)	$ (3)