Postretirement Benefit Plans - Weighted Average Assumptions Used (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
United States | Defined benefit plan
Weighted average assumptions used to determine benefit obligations:
Discount rate (in percent)	4.37%	3.75%
Long-term pay progression (in percent)	3.30%	3.30%
Weighted average assumptions used to determine net periodic benefit cost:
Discount rate (in percent)	3.77%	4.21%
Long term rate of return on plan assets (in percent)	4.80%	4.30%
Long-term pay progression (in percent)	3.30%	3.30%
United States | Retiree health care plan
Weighted average assumptions used to determine benefit obligations:
Discount rate (in percent)	4.30%	3.63%
Weighted average assumptions used to determine net periodic benefit cost:
Discount rate (in percent)	3.63%	4.08%
Long term rate of return on plan assets (in percent)	4.10%	4.10%
Non-U.S. | Defined benefit plan
Weighted average assumptions used to determine benefit obligations:
Discount rate (in percent)	1.85%	1.84%
Long-term pay progression (in percent)	2.96%	2.96%
Weighted average assumptions used to determine net periodic benefit cost:
Discount rate (in percent)	1.84%	1.76%
Long term rate of return on plan assets (in percent)	2.58%	2.60%
Long-term pay progression (in percent)	2.96%	3.11%