Employee Benefits (Schedule Of Accumulated Benefit Obligations In Excess Of Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 650	$ 614
Domestic Plan [Member] | Other Postretirement Plan Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0	$ 0
Domestic Plan [Member] | Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	650	614	51
Domestic Plan [Member] | Defined Benefit Plans [Member] | Underfunded Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation	(807)	(799)
Accumulated benefit obligation	(807)	(799)
Fair value of plan assets	650	614
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18	16
Foreign Plan [Member] | Other Postretirement Plan Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0	0
Foreign Plan [Member] | Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18	16	$ 0
Foreign Plan [Member] | Defined Benefit Plans [Member] | Underfunded Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation	(128)	(113)
Accumulated benefit obligation	(126)	(110)
Fair value of plan assets	$ 5	$ 5
Minimum [Member] | Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Funded Status, Percentage	80.00%