Investment And Other Income (Loss) (Components Of Investment And Other Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Investment And Other Income (Loss) [Abstract]
Interest and dividend income	$ 1	$ 1	$ 4	$ 3
Pension and OPEB benefit (costs)	(11)	5	(22)	10
All other, net	1	(1)
Total investment and other income (loss), net	$ (9)	$ 5	$ (18)	$ 13