Guaranteed Benefit Features (Summary Of Guaranteed Death Benefit Liabilities) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Guaranteed Benefit Features [Abstract]
Balance as of beginning-of-year	$ 89	$ 73
Changes in reserves	59	26
Benefits paid	(17)	(13)
Balance as of end-of-period	$ 131	$ 86