Investments (Details 4) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Realized capital gains and losses by asset type
Realized capital gains and losses	$ 57	$ (451)	$ 153	$ (799)
Fixed income securities
Realized capital gains and losses by asset type
Realized capital gains and losses	39	(188)	12	(324)
Equity securities
Realized capital gains and losses by asset type
Realized capital gains and losses	15	45	137	59
Mortgage loans
Realized capital gains and losses by asset type
Realized capital gains and losses	(3)	(28)	(9)	(53)
Limited partnership interests
Realized capital gains and losses by asset type
Realized capital gains and losses	53	26	121	5
Derivatives
Realized capital gains and losses by asset type
Realized capital gains and losses	(53)	(308)	(120)	(493)
Other:
Realized capital gains and losses by asset type
Realized capital gains and losses	$ 6	$ 2	$ 12	$ 7