Investments (Details 4) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Realized capital gains and losses by asset type
Realized capital gains and losses	$ 139	$ 54
Fixed income securities
Realized capital gains and losses by asset type
Realized capital gains and losses	80	36
Equity securities
Realized capital gains and losses by asset type
Realized capital gains and losses	78	22
Mortgage loans
Realized capital gains and losses by asset type
Realized capital gains and losses	0	3
Limited partnership interests
Realized capital gains and losses by asset type
Realized capital gains and losses	6	2
Derivatives
Realized capital gains and losses by asset type
Realized capital gains and losses	(25)	(12)
Other
Realized capital gains and losses by asset type
Realized capital gains and losses	$ 0	$ 3