Employee Benefit Plans (Principal Assumptions In Developing Net Periodic Pension Cost) (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Weighted-Average Interest Crediting Rate	2.20%	3.30%
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate (as a percent)	2.90%	3.90%
Expected return on plan assets (as a percent)	6.60%	6.50%
Rate of compensation increase (as a percent)	4.90%	4.90%
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate (as a percent)	3.20%	4.30%