Employee Benefits (Weighted-Average Assumptions Used) (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Qualified Pension Plan [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	2.71%	3.42%
Rate of compensation increase	3.75%	3.75%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Equivalent single discount rate for benefit obligations	3.42%	4.38%	3.69%
Equivalent single discount rate for service cost	3.54%	4.44%	3.76%
Equivalent single discount rate for interest cost	3.07%	4.12%	3.42%
Expected long-term return on plan assets	5.75%	5.75%	6.75%
Rate of compensation increase	3.75%	3.75%	3.75%
Non-Qualified Retirement Plans [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	2.50%	3.30%
Rate of compensation increase	3.75%	3.75%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Equivalent single discount rate for benefit obligations	3.30%	4.28%	3.58%
Equivalent single discount rate for service cost	3.62%	4.48%	3.79%
Equivalent single discount rate for interest cost	2.93%	3.98%	3.22%
Rate of compensation increase	3.75%	3.75%	3.75%