Investments (Details 4) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Realized capital gains and losses by asset type
Realized capital gains and losses	$ (149)	$ 139
Fixed income securities
Realized capital gains and losses by asset type
Realized capital gains and losses	(71)	80
Equity securities
Realized capital gains and losses by asset type
Realized capital gains and losses	(90)	78
Limited partnership interests
Realized capital gains and losses by asset type
Realized capital gains and losses	26	6
Derivatives
Realized capital gains and losses by asset type
Realized capital gains and losses	(9)	(25)
Other
Realized capital gains and losses by asset type
Realized capital gains and losses	$ (5)	$ 0