Regulatory Matters - Summary of Virginia Power Electric Transmission Project Applied (Detail) - Virginia Electric and Power Company $ in Millions	3 Months Ended
	Mar. 31, 2022 USD ($) kV mi
Elmont-Ladysmith rebuild and related projects in the Counties of Hanover and Caroline, Virginia
Public Utilities General Disclosures [Line Items]
Application Date	2021-04
Approval Date	2022-04
Type of Line | kV	500
Miles of Lines | mi	26
Cost Estimate | $	$ 95
Nimbus line loop and substation and new 230 kV line in the County of Loudon, Virginia
Public Utilities General Disclosures [Line Items]
Application Date	2022-02
Type of Line | kV	230
Miles of Lines | mi	1
Cost Estimate | $	$ 40