Pension and Other Post-Retirement Benefits - Weighted Average Asset Allocations of Foreign Funded (Details) - Foreign Plan [Member] - Defined Benefit Pension [Member]	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Target Allocation Percentage	1
Weighted-average asset allocations of its foreign funded pension plan
Actual plan asset allocations	100.00%	100.00%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Target Allocation Percentage	0.368
Weighted-average asset allocations of its foreign funded pension plan
Actual plan asset allocations	36.00%	37.70%
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Target Allocation Percentage	0.632
Weighted-average asset allocations of its foreign funded pension plan
Actual plan asset allocations	64.00%	62.30%