Benefit Plans (Weighted Average Asset Allocations) (Details)	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations	100.00%	100.00%
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations	4.90%	3.30%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations	48.30%	53.10%
Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocations	46.80%	43.60%