Pension and Other Retirement Plans - Weighted Average Assumptions (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate for expense	3.55%	4.05%
Discount rate for obligations	4.20%	3.55%
Long-term rate of return on plans’ assets for expense	6.40%	6.60%
Other Postretirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate for expense	3.10%	3.30%
Discount rate for obligations	3.75%	3.10%
Long-term rate of return on plans’ assets for expense	0.00%	0.00%