Employee Benefit Plans (Target and Actual Asset Allocation for Pension Plan by Asset Category) (Details) - Employee Pension Plans	Dec. 31, 2020	Dec. 31, 2019
Pension Plan Assets
Target asset allocation (as a percent)	100.00%
Actual asset allocation (as a percent)	100.00%	100.00%
Cash
Pension Plan Assets
Target asset allocation (as a percent)	5.00%
Actual asset allocation (as a percent)	5.00%	4.00%
Domestic Equity Funds
Pension Plan Assets
Target asset allocation (as a percent)	35.00%
Actual asset allocation (as a percent)	34.00%	47.00%
International Equity Funds
Pension Plan Assets
Target asset allocation (as a percent)	15.00%
Actual asset allocation (as a percent)	17.00%	18.00%
Fixed income funds
Pension Plan Assets
Target asset allocation (as a percent)	45.00%
Actual asset allocation (as a percent)	44.00%	31.00%