Pension and Postretirement Benefit Plans - Significant Weighted Average Assumptions Used in Measurement of OPEB Obligations (Details) - Other Postretirement Benefits Plan [Member] - Foreign Plan [Member]				12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
OPEB benefit obligations:
Discount rate	3.41%	3.69%	3.96%	3.41%	3.69%	3.96%
Net periodic benefit cost:
Discount rate				3.70%	3.45%	3.84%
Initial health care cost trend rate				5.07%	5.32%	5.62%
Ultimate health care cost trend rate	5.07%	5.02%	5.03%	5.07%	5.02%	5.03%
Year ultimate reached	2018	2018	2018