Guaranteed Benefit Features (Summary Of Guaranteed Death Benefit Liabilities) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Guaranteed Benefit Features [Abstract]
Balance as of beginning-of-year	$ 117	$ 161
Changes in reserves	46	(16)
Benefits paid	(21)	(15)
Balance as of end-of-period	$ 142	$ 130