Defined Benefit Pension Plans (Weighted-Average Assumptions Used) (Details)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Qualified Pension Plan [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Equivalent single discount rate for benefit obligations	4.38%	3.69%
Equivalent single discount rate for service cost	4.44%	3.76%
Equivalent single discount rate for interest cost	4.12%	3.42%
Expected long-term return on plan assets	5.75%	6.75%
Rate of compensation increase	3.75%	3.75%
Non-Qualified Retirement Plans [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Equivalent single discount rate for benefit obligations	4.28%	3.58%
Equivalent single discount rate for service cost	4.48%	3.79%
Equivalent single discount rate for interest cost	3.98%	3.22%
Rate of compensation increase	3.75%	3.75%