Benefit Plans Benefit Plans (Weighted Average Assumptions) (Details)		12 Months Ended
		Dec. 31, 2017 Rate	Dec. 31, 2016 Rate
Foreign Plan [Member]
Benefit Obligation:
Discount rate		5.23%	5.83%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	[1]	5.83%	6.10%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets		5.30%	5.09%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase		4.86%	4.45%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase		4.65%	4.86%
UNITED STATES
Benefit Obligation:
Discount rate		3.67%	4.28%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate		4.28%	4.44%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets		6.67%	6.67%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase		3.34%	3.34%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase		3.34%	3.34%

[1] Includes an inflation factor that is used to calculate future periodic benefit cost, but is not used to calculate the benefit obligation.