Employee Retirement Plans and Postretirement Benefits Weighted Average Assumptions (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlement discount rate	3.44%	3.01%	3.36%
Rate of compensation increase (as a percent)	2.00%	2.00%	2.00%
Expected return on plan assets (as a percent)	4.38%	4.10%	4.83%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.55%	3.44%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase	2.00%	2.00%
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlement discount rate	3.92%	3.34%	3.76%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.91%	3.92%
Other Postretirement Benefits Plan [Member] | Maximum
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate	6.50%	6.75%	7.00%
Year that rate reaches ultimate trend rate	2019	2018	2017
Other Postretirement Benefits Plan [Member] | Minimum
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate	4.50%	4.50%	4.50%
Year that rate reaches ultimate trend rate	2037	2037	2037