Guaranteed Benefit Features (Summary Of Guaranteed Death Benefit Liabilities) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Guaranteed Benefit Features [Abstract]
Balance as of beginning-of-year	$ 104	$ 84
Changes in reserves	(4)	(17)
Benefits paid	(7)	(12)
Balance as of end-of-period	$ 93	$ 55

Sum of the amount of expected guaranteed benefits in excess of the projected account balances for minimum guaranteed benefit contracts as of the balance sheet date for all guaranteed benefit types.

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Total of amount of guaranteed minimum benefit expense incurred during the period presented, resulting in an increase to the liability for expected guaranteed minimum benefits in excess of projected account values, for all guaranteed benefit types.

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- Definition

Total amount of guaranteed minimum benefit payments to policyholders and contract holders, during the period presented, resulting in a decrease to the liability for expected guaranteed minimum benefits in excess of projected account values, for all guaranteed benefit types.

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