Fair Value (Details Textuals) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Fair Value (Textuals) [Abstract]
Other changes in estimated fair value affecting MSRs	$ 0	$ 0
Call options in equity securities	(74)		(72)
Call options in fixed maturity securities	0		2
Transfers between Levels 1 and 2	37	0
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liquidation period for other limited partnership interests	2 years
Liquidation period for real estate joint venture commitments	2 years
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liquidation period for other limited partnership interests	10 years
Liquidation period for real estate joint venture commitments	10 years
Non Recurring [Member] | Other limited partnership interests [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unfunded commitment for investments	3	0
Non Recurring [Member] | Real estate joint ventures [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unfunded commitment for investments	$ 3	$ 0