Investments (Details 4) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Realized capital gains and losses by asset type
Realized capital gains and losses	$ 30	$ 694	$ 594
Fixed income securities
Realized capital gains and losses by asset type
Realized capital gains and losses	212	130	262
Equity securities
Realized capital gains and losses by asset type
Realized capital gains and losses	(50)	582	327
Mortgage loans
Realized capital gains and losses by asset type
Realized capital gains and losses	6	2	20
Limited partnership interests
Realized capital gains and losses by asset type
Realized capital gains and losses	(93)	13	(5)
Derivatives
Realized capital gains and losses by asset type
Realized capital gains and losses	(21)	(38)	(10)
Other
Realized capital gains and losses by asset type
Realized capital gains and losses	$ (24)	$ 5	$ 0