Investment And Other Income (Loss) (Components Of Investment And Other Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Investment And Other Income (Loss) [Abstract]
Interest and dividend income	$ 2	$ 2	$ 6	$ 5
Pension and OPEB benefit (costs)	(12)	2	(34)	12
All other, net		(1)		(1)
Total investment and other income (loss), net	$ (10)	$ 3	$ (28)	$ 16