Benefit Plans Schedule Of Percentage Of Allocation Of Plan Assets Table (Details)	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Total, percentage	100.00%
Cash and cash equivalents, percentage	1.20%	1.70%
Equity securities, percentage	37.00%	36.90%
Debt securities, percentage	50.20%	49.70%
Other investments, percentage	11.60%	11.70%
Total, percentage	100.00%	100.00%
Maximum | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Total, percentage	10.00%
Maximum | Equity securities: Equity commingled funds
Defined Benefit Plan Disclosure [Line Items]
Total, percentage	60.00%
Maximum | Debt securities: Government bonds
Defined Benefit Plan Disclosure [Line Items]
Total, percentage	100.00%
Maximum | Other investments
Defined Benefit Plan Disclosure [Line Items]
Total, percentage	100.00%
Minimum | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Total, percentage	0.00%
Minimum | Equity securities: Equity commingled funds
Defined Benefit Plan Disclosure [Line Items]
Total, percentage	0.00%
Minimum | Debt securities: Government bonds
Defined Benefit Plan Disclosure [Line Items]
Total, percentage	15.00%
Minimum | Other investments
Defined Benefit Plan Disclosure [Line Items]
Total, percentage	0.00%