Other Expenses (Schedule Of The Activity And Balances Associated With Restructuring Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Restructuring Cost And Reserve [Line Items]
Beginning balance	$ 110	$ 76
Ending balance	50	110
Prior years' restructurings [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve activity	(60)	34
Other Current Liabilities [Member]
Restructuring Cost And Reserve [Line Items]
Beginning balance	48	13
Ending balance	19	48
Other Current Liabilities [Member] | Prior years' restructurings [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve activity	(29)	35
Other Long-Term Liabilities [Member]
Restructuring Cost And Reserve [Line Items]
Beginning balance	62	63
Ending balance	31	62
Other Long-Term Liabilities [Member] | Prior years' restructurings [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve activity	$ (31)	$ (1)