Pensions and Postretirement Benefits (Summary of Pension Plan Weighted-Average Asset Allocation) (Details)	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Target allocation	100.00%
Weighted-average asset allocations	100.00%	100.00%
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	61.50%	59.20%
Debt securities
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	20.00%	25.50%
Other
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	18.50%	15.30%
Minimum | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation	45.00%
Minimum | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation	15.00%
Minimum | Other
Defined Benefit Plan Disclosure [Line Items]
Target allocation	0.00%
Maximum | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation	75.00%
Maximum | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation	35.00%
Maximum | Other
Defined Benefit Plan Disclosure [Line Items]
Target allocation	25.00%