Investments (Schedule Of Changes in Amount Of Credit Losses Of OTTI Recognized In Net Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Investments [Abstract]
Balance as of beginning-of-period	$ 244	$ 356	$ 337	$ 358
Increases attributable to:
Credit losses on securities for which an OTTI was not previously recognized	1	2	11	4
Credit losses on securities for which an OTTI was previously recognized	1		3	1
Decreases attributable to:
Securities sold, paid down or matured	(37)	(5)	(142)	(10)
Balance as of end-of-period	$ 209	$ 353	$ 209	$ 353