Employee Benefit Plans (Schedule of Allocation of Plan Assets) (Details)	Dec. 31, 2019	Dec. 31, 2018
Pension Benefit Plan [Member]
Allocation of plan assets	100.00%	100.00%
Pension Benefit Plan [Member] | Commodities [Member]
Allocation of plan assets	1.50%	2.40%
Target plan allocations	5.00%
Pension Benefit Plan [Member] | Cash [Member]
Allocation of plan assets	0.50%	1.60%
Target plan allocations	2.00%
Pension Benefit Plan [Member] | Debt Securities [Member]
Allocation of plan assets	36.50%	36.50%
Target plan allocations	38.00%
Pension Benefit Plan [Member] | Equity Securities [Member]
Allocation of plan assets	61.50%	59.50%
Target plan allocations	55.00%
Other Benefits Plan [Member]
Allocation of plan assets	100.00%	100.00%
Other Benefits Plan [Member] | Commodities [Member]
Allocation of plan assets	0.00%	0.00%
Other Benefits Plan [Member] | Cash [Member]
Allocation of plan assets	7.00%	8.00%
Other Benefits Plan [Member] | Debt Securities [Member]
Allocation of plan assets	33.00%	37.30%
Other Benefits Plan [Member] | Equity Securities [Member]
Allocation of plan assets	60.00%	54.70%
Target plan allocations	43.00%