Derivative Financial Instruments (Schedule Of Gains And Losses Of Derivative Financial Instruments Without Hedge Designation) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type	$ (48)	$ (106)	$ 81
Net Investment Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type	(14)	(75)	21
Net Investment Income [Member] | Equity Options - Purchased [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type	(9)	(16)	(50)
Net Investment Income [Member] | Equity Options - Written [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type	8	22	58
Net Investment Income [Member] | Equity Futures - Long [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type	(11)	(6)	14
Net Investment Income [Member] | Equity Futures - Short [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type	(1)	(4)
Net Investment Income [Member] | Equity Swaps - Long [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type	4
Net Investment Income [Member] | Equity Swaps - Short [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type	(4)
Net Investment Income [Member] | Currency Options- Short [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type		(1)
Net Investment Income [Member] | Options On Government Securities - Short [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type		(66)
Net Investment Income [Member] | Interest Rate Futures - Long [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type		(11)	5
Net Investment Income [Member] | Interest Rate Futures- Short [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type		19	(24)
Net Investment Income [Member] | Other Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type	(1)	(3)	7
Net Investment Income [Member] | Credit Default Swaps - Sold Protection [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type	1		12
Net Investment Income [Member] | Credit Default Swaps - Purchased Protection [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type			(8)
Net Investment Income [Member] | Currency Forwards - Long [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type			(8)
Net Investment Income [Member] | Currency Forwards - Short [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type	(1)	(9)	15
Investment Gains (Losses) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type	(34)	(31)	51
Investment Gains (Losses) [Member] | Equity Options - Written [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type			15
Investment Gains (Losses) [Member] | Interest Rate Futures- Short [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type			21
Investment Gains (Losses) [Member] | Interest Rate Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type	(34)	(44)	59
Investment Gains (Losses) [Member] | Commodity Forwards - Short [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type		14
Investment Gains (Losses) [Member] | Credit Default Swaps - Sold Protection [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type			3
Investment Gains (Losses) [Member] | Credit Default Swaps - Purchased Protection [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type		(1)	(47)
Other Revenues [Member] | Currency Forwards - Short [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives without hedge designation, gains (losses), by instrument type			$ 9