Pensions and Other Postretirement Benefits - Allocation of Plan Assets (Details) - Pension Benefit Plans	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Target plan asset allocations	100.00%
Actual plan asset allocations	100.00%	100.00%
Cash
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Target plan asset allocations	0.20%
Actual plan asset allocations	13.60%	5.00%
Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Target plan asset allocations	8.40%
Actual plan asset allocations	7.70%	8.10%
Fixed Income Securities
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Target plan asset allocations	85.20%
Actual plan asset allocations	68.60%	79.50%
Other Investments
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Target plan asset allocations	6.20%
Actual plan asset allocations	10.10%	7.40%