Benefit Plans (Actuarial Assumptions for Net Cost or Benefit) (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Interest crediting rate	5.00%	5.00%	5.00%
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.25%	3.55%	3.95%
Expected long term rate of return	7.50%	7.50%	7.50%
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.55%	2.75%	2.75%