Restructuring and Transaction Costs (Schedule Of The Activity And Balances Associated With Restructuring Liabilities) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Restructuring Cost And Reserve [Line Items]
Beginning balance	$ 172	$ 21
Ending balance	224	12
Reduction Of Workforce
Restructuring Cost And Reserve [Line Items]
Restructuring reserve activity	61
Prior years' restructurings [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve activity	(9)	(9)
Other Current Liabilities [Member]
Restructuring Cost And Reserve [Line Items]
Beginning balance	35	20
Ending balance	94	11
Other Current Liabilities [Member] | Reduction Of Workforce
Restructuring Cost And Reserve [Line Items]
Restructuring reserve activity	61
Other Current Liabilities [Member] | Prior years' restructurings [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve activity	(2)	(9)
Other Long-Term Liabilities [Member]
Restructuring Cost And Reserve [Line Items]
Beginning balance	137	1
Ending balance	130	$ 1
Other Long-Term Liabilities [Member] | Prior years' restructurings [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve activity	$ (7)