Summary Of Significant Accounting Policies (Schedule Of Depreciation Rates) (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Wildcat Point [Member]
Property, Plant and Equipment [Line Items]
Depreciation Rates	3.10%	3.10%	3.10%
North Anna [Member]
Property, Plant and Equipment [Line Items]
Depreciation Rates	3.30%	3.30%	3.30%
Clover [Member]
Property, Plant and Equipment [Line Items]
Depreciation Rates	1.90%	1.90%	1.90%
Louisa [Member]
Property, Plant and Equipment [Line Items]
Depreciation Rates	3.10%	3.10%	3.10%
Marsh Run [Member]
Property, Plant and Equipment [Line Items]
Depreciation Rates	3.00%	3.00%	3.00%