Benefit Plans (Net Pension and Postretirement Cost Weighted-Average Assumptions) (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate - service cost	2.14%	1.92%	1.68%
Discount rate - interest cost	1.35%	1.25%	1.27%
Expected rate of return on plan assets	4.70%	4.76%	4.80%
Rate of compensation increase	1.86%	1.65%	1.68%
Interest crediting rate	3.40%	3.40%	3.40%
Postretirement [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate - service cost	3.97%	3.79%	3.68%
Discount rate - interest cost	3.97%	3.79%	3.68%
Health care cost trend rate	6.17%	6.17%	7.15%