Restructuring And Other Charges (Changes In Restructuring Reserve) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring And Other Charges [Abstract]
Restructuring Reserve, Beginning Balance	$ 15	$ 18
Severance costs	7	38	$ 12
Transformation initiative costs	8	46	23
Other restructuring costs	72	40
Cash payments during the period	(100)	(127)
Restructuring Reserve, Ending Balance	$ 2	$ 15	$ 18