Pension, Post-Retirement and Post-Employment Plans - Key Assumptions Used to Determine Benefit Obligations (Details)	Dec. 31, 2018	Dec. 31, 2017
Pension Plan and SERP | Domestic
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	4.30%	3.70%
Rate of compensation increase	3.50%	3.50%
Pension Plan and SERP | Foreign
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	1.50%	1.30%
Rate of compensation increase	3.40%	3.30%
Post-retirement Medical Benefits | Domestic
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	4.30%	3.70%
Post-retirement Medical Benefits | Foreign
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	9.20%	9.90%