Restructuring and Transaction Costs (Schedule Of The Activity And Balances Associated With Restructuring Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Restructuring Cost And Reserve [Line Items]
Beginning balance	$ 21	$ 42
Restructuring reserve activity	166
Ending balance	172	21
Prior years' restructurings [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve activity	(18)	(39)
Reduction of workforce [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve activity	3	18
Other Current Liabilities [Member]
Restructuring Cost And Reserve [Line Items]
Beginning balance	20	39
Restructuring reserve activity	30
Ending balance	35	20
Other Current Liabilities [Member] | Prior years' restructurings [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve activity	(18)	(37)
Other Current Liabilities [Member] | Reduction of workforce [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve activity	3	18
Other Long-Term Liabilities [Member]
Restructuring Cost And Reserve [Line Items]
Beginning balance	1	3
Restructuring reserve activity	136
Ending balance	$ 137	1
Other Long-Term Liabilities [Member] | Prior years' restructurings [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve activity		$ (2)