Restructuring and Transaction Costs and Other Expenses (Schedule Of The Activity And Balances Associated With Restructuring Liabilities) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Restructuring Cost And Reserve [Line Items]
Beginning balance	$ 50	$ 110
Ending balance	89	81
Reduction of workforce [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve activity	48
Prior years' restructurings [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve activity	(9)	(29)
Other Current Liabilities [Member]
Restructuring Cost And Reserve [Line Items]
Beginning balance	19	48
Ending balance	66	31
Other Current Liabilities [Member] | Reduction of workforce [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve activity	48
Other Current Liabilities [Member] | Prior years' restructurings [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve activity	(1)	(17)
Other Long-Term Liabilities [Member]
Restructuring Cost And Reserve [Line Items]
Beginning balance	31	62
Ending balance	23	50
Other Long-Term Liabilities [Member] | Prior years' restructurings [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve activity	$ (8)	$ (12)