Benefit Obligations (Schedule of Percentage of US and International Fair Value of Plan Assets) (Details)	Dec. 31, 2017	Dec. 31, 2016
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets Percentage	100.00%	100.00%
Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets Percentage	88.00%	88.00%
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Assets Percentage	12.00%	12.00%