Investments (Schedule Of Changes in Amount Of Credit Losses Of OTTI Recognized In Net Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Investments [Abstract]
Balance as of beginning-of-period	$ 340	$ 359	$ 337	$ 358
Increases attributable to:
Credit losses on securities for which an OTTI was not previously recognized	4	1	10	2
Credit losses on securities for which an OTTI was previously recognized			2	1
Decreases attributable to:
Securities sold, paid down or matured	(100)	(4)	(105)	(5)
Balance as of end-of-period	$ 244	$ 356	$ 244	$ 356