Fair Value Measurements (Schedule Of Significant Unobservable Inputs Used In Level 3 Liability Valuations) (Details) (Guaranteed Living Benefits [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Fair Value	$ 863	[1]
Valuation Technique	Actuarial model	[1]
Maximum [Member]
Significant Unobservable Inputs Lapse rate	30.00%
Significant Unobservable Inputs Annuitization rate	50.00%
Minimum [Member]
Significant Unobservable Inputs Lapse rate	1.00%
Significant Unobservable Inputs Annuitization rate	0.00%

[1] Discussion of the most significant inputs used in the fair value measurement of GLB and the sensitivity of those assumptions is included within Note 4 a) Guaranteed living benefits.