Derivatives and Hedge Accounting Activities (Volume of Derivative Activity) (Details) - 9 months ended Sep. 30, 2016 MMcf in Thousands, € in Millions, $ in Millions		USD ($) MWh MMcf gal	EUR (€)
Fixed Price - Natural Gas - Current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)	[1]	104
Fixed Price - Natural Gas - Non-current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)	[1]	23
Basis - Natural Gas - Current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)		261
Basis - Natural Gas - Non-current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)		626
Fixed Price - Electricity - Current Derivative Contract
Derivative [Line Items]
Volume of electricity (MWh) | MWh		8,274,639
Fixed Price - Electricity - Non-current Derivative Contract
Derivative [Line Items]
Volume of electricity (MWh) | MWh		659,440
Financial Transmission Rights - Electricity- Current Derivative Contract
Derivative [Line Items]
Volume of electricity (MWh) | MWh		72,352,190
Financial Transmission Rights - Electricity- Non-current Derivative Contract
Derivative [Line Items]
Volume of electricity (MWh) | MWh		0
Liquids - Current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal) | gal	[2]	39,269,554
Liquids - Non-current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal) | gal	[2]	0
Foreign currency
Derivative [Line Items]
Interest rate (US Dollars, Euros) | €			€ 250
Foreign Exchange - Current Derivative Contract
Derivative [Line Items]
Interest rate (US Dollars, Euros) | $	[3],[4]	$ 0
Foreign Exchange - Non- Current Derivative Contract
Derivative [Line Items]
Interest rate (US Dollars, Euros) | $	[3],[4]	280
Interest Rate - Current Derivative Contract
Derivative [Line Items]
Interest rate (US Dollars, Euros) | $	[4]	2,200
Interest Rate - Non-current Derivative Contract
Derivative [Line Items]
Interest rate (US Dollars, Euros) | $	[4]	$ 1,600
Virginia Electric and Power Company | Fixed Price - Natural Gas - Current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)	[5]	32
Virginia Electric and Power Company | Fixed Price - Natural Gas - Non-current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)	[5]	12
Virginia Electric and Power Company | Basis - Natural Gas - Current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)		126
Virginia Electric and Power Company | Basis - Natural Gas - Non-current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)		558
Virginia Electric and Power Company | Financial Transmission Rights - Electricity- Current Derivative Contract
Derivative [Line Items]
Volume of electricity (MWh) | MWh		70,978,901
Virginia Electric and Power Company | Financial Transmission Rights - Electricity- Non-current Derivative Contract
Derivative [Line Items]
Volume of electricity (MWh) | MWh		0
Virginia Electric and Power Company | Interest Rate - Current Derivative Contract
Derivative [Line Items]
Interest rate (US Dollars, Euros) | $		$ 1,200
Virginia Electric and Power Company | Interest Rate - Non-current Derivative Contract
Derivative [Line Items]
Interest rate (US Dollars, Euros) | $		$ 600
Dominion Gas Holdings, LLC | Fixed Price - Natural Gas - Current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)		6
Dominion Gas Holdings, LLC | Fixed Price - Natural Gas - Non-current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)		0
Dominion Gas Holdings, LLC | Basis - Natural Gas - Current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)		6
Dominion Gas Holdings, LLC | Basis - Natural Gas - Non-current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)		0
Dominion Gas Holdings, LLC | Liquids - Current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal) | gal		33,095,554
Dominion Gas Holdings, LLC | Liquids - Non-current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal) | gal		0
Dominion Gas Holdings, LLC | Foreign currency
Derivative [Line Items]
Interest rate (US Dollars, Euros) | €			€ 250
Dominion Gas Holdings, LLC | Foreign Exchange - Current Derivative Contract
Derivative [Line Items]
Interest rate (US Dollars, Euros) | $	[6]	$ 0
Dominion Gas Holdings, LLC | Foreign Exchange - Non- Current Derivative Contract
Derivative [Line Items]
Interest rate (US Dollars, Euros) | $	[6]	$ 280

[1] Includes options.

[2] Includes NGLs and oil.

[3] Euro equivalent volumes are €250,000,000.

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

[5] Includes options.

[6] Maturity is determined based on final settlement period. Euro equivalent volumes are €250,000,000.