Investment And Other Income (Loss) (Components Of Investment And Other Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Investment And Other Income (Loss) [Abstract]
Interest and dividend income		$ 2	$ 4	$ 6
Pension and OPEB costs	$ (16)	(12)	(35)	(34)
All other, net	2		2
Total investment and other loss, net	$ (14)	$ (10)	$ (29)	$ (28)