Wholesale Power Contracts (Schedule Of Revenues From Member Distribution Cooperatives) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Member distribution revenue	$ 1,075.4	$ 1,024.3	$ 951.1
Rappahannock Electric Cooperative [Member]
Related Party Transaction [Line Items]
Member distribution revenue	333.0	312.4	288.6
Shenandoah Valley Electric Cooperative [Member]
Related Party Transaction [Line Items]
Member distribution revenue	189.9	192.1	180.9
Delaware Electric Cooperative, Inc. [Member]
Related Party Transaction [Line Items]
Member distribution revenue	141.2	148.1	140.0
Mecklenburg Electric Cooperative [Member]
Related Party Transaction [Line Items]
Member distribution revenue	101.9	71.0	54.3
Choptank Electric Cooperative, Inc. [Member]
Related Party Transaction [Line Items]
Member distribution revenue	89.6	95.7	92.3
Southside Electric Cooperative [Member]
Related Party Transaction [Line Items]
Member distribution revenue	79.7	74.5	67.5
A&N Electric Cooperative [Member]
Related Party Transaction [Line Items]
Member distribution revenue	58.3	56.7	55.1
Prince George Electric Cooperative [Member]
Related Party Transaction [Line Items]
Member distribution revenue	29.3	27.0	25.8
Northern Neck Electric Cooperative [Member]
Related Party Transaction [Line Items]
Member distribution revenue	25.7	21.7	21.5
Community Electric Cooperative [Member]
Related Party Transaction [Line Items]
Member distribution revenue	15.3	13.9	13.9
BARC Electric Cooperative [Member]
Related Party Transaction [Line Items]
Member distribution revenue	$ 11.5	$ 11.2	$ 11.2