Investments (Details 4) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Realized capital gains and losses by asset type
Realized capital gains and losses	$ 264	$ (144)	$ 417	$ (943)
Fixed income securities
Realized capital gains and losses by asset type
Realized capital gains and losses	603	84	615	(240)
Equity securities
Realized capital gains and losses by asset type
Realized capital gains and losses	(77)	83	60	142
Mortgage loans
Realized capital gains and losses by asset type
Realized capital gains and losses	(28)	(1)	(37)	(54)
Limited partnership interests
Realized capital gains and losses by asset type
Realized capital gains and losses	8	(20)	129	(15)
Derivatives
Realized capital gains and losses by asset type
Realized capital gains and losses	(234)	(286)	(354)	(779)
Other:
Realized capital gains and losses by asset type
Realized capital gains and losses	$ (8)	$ (4)	$ 4	$ 3