Derivatives and Hedge Accounting Activities (Volume of Derivative Activity) (Detail) - 3 months ended Mar. 31, 2020		USD ($) MWh Bcf gal	EUR (€)
Fixed Price - Natural Gas - Current Derivative Contract
Derivative [Line Items]
Volume of derivative activity	[1]	81
Fixed Price - Natural Gas - Current Derivative Contract | Virginia Electric and Power Company
Derivative [Line Items]
Volume of derivative activity	[1]	37
Basis - Natural Gas - Current Derivative Contract
Derivative [Line Items]
Volume of derivative activity		268
Basis - Natural Gas - Current Derivative Contract | Virginia Electric and Power Company
Derivative [Line Items]
Volume of derivative activity		160
Fixed Price - Electricity - Current Derivative Contract
Derivative [Line Items]
Volume of electricity | MWh		3,088,875
Fixed Price - Electricity - Current Derivative Contract | Virginia Electric and Power Company
Derivative [Line Items]
Volume of electricity | MWh		18,836,472
Financial Transmission Rights - Electricity- Current Derivative Contract
Derivative [Line Items]
Volume of electricity | MWh		18,836,472
Liquids - Current Derivative Contract
Derivative [Line Items]
Volume of derivative activity | gal	[2]	39,690,000
Interest Rate - Current Derivative Contract
Derivative [Line Items]
Interest rate / Foreign currency (US Dollars, Euros) | $	[3]	$ 2,450,000,000
Interest Rate - Current Derivative Contract | Virginia Electric and Power Company
Derivative [Line Items]
Interest rate / Foreign currency (US Dollars, Euros) | $	[3]	900,000,000
Interest Rate - Current Derivative Contract | Dominion Energy Gas Holdings, LLC
Derivative [Line Items]
Interest rate / Foreign currency (US Dollars, Euros) | $	[3]	$ 250,000,000
Foreign Exchange - Current Derivative Contract
Derivative [Line Items]
Interest rate / Foreign currency (US Dollars, Euros) | €	[3]		€ 0
Foreign Exchange - Current Derivative Contract | Dominion Energy Gas Holdings, LLC
Derivative [Line Items]
Interest rate / Foreign currency (US Dollars, Euros) | €	[3]		0
Fixed Price - Natural Gas - Non-current Derivative Contract
Derivative [Line Items]
Volume of derivative activity	[1]	36
Fixed Price - Natural Gas - Non-current Derivative Contract | Virginia Electric and Power Company
Derivative [Line Items]
Volume of derivative activity	[1]	14
Basis - Natural Gas - Non-current Derivative Contract
Derivative [Line Items]
Volume of derivative activity		574
Basis - Natural Gas - Non-current Derivative Contract | Virginia Electric and Power Company
Derivative [Line Items]
Volume of derivative activity		536
Fixed Price - Electricity - Non-current Derivative Contract
Derivative [Line Items]
Volume of electricity | MWh		0
Financial Transmission Rights - Electricity- Non-current Derivative Contract
Derivative [Line Items]
Volume of electricity | MWh		0
Financial Transmission Rights - Electricity- Non-current Derivative Contract | Virginia Electric and Power Company
Derivative [Line Items]
Volume of electricity | MWh		0
Liquids - Non-current Derivative Contract
Derivative [Line Items]
Volume of derivative activity | gal	[2]	0
Interest Rate - Non-current Derivative Contract
Derivative [Line Items]
Interest rate / Foreign currency (US Dollars, Euros) | $	[3]	$ 5,582,850,761
Interest Rate - Non-current Derivative Contract | Virginia Electric and Power Company
Derivative [Line Items]
Interest rate / Foreign currency (US Dollars, Euros) | $		1,150,000,000
Interest Rate - Non-current Derivative Contract | Dominion Energy Gas Holdings, LLC
Derivative [Line Items]
Interest rate / Foreign currency (US Dollars, Euros) | $	[3]	$ 1,050,000,000
Foreign Exchange - Non- Current Derivative Contract
Derivative [Line Items]
Interest rate / Foreign currency (US Dollars, Euros) | €	[3]		250,000,000
Foreign Exchange - Non- Current Derivative Contract | Dominion Energy Gas Holdings, LLC
Derivative [Line Items]
Interest rate / Foreign currency (US Dollars, Euros) | €	[3]		€ 250,000,000

[1] Includes options.

[2] Includes NGLs.

[3] Maturity is determined based on final settlement period.