Derivatives and Hedge Accounting Activities (Volume of Derivative Activity) (Details) - 3 months ended Mar. 31, 2017 MMcf in Thousands, € in Millions		USD ($) MWh MMcf gal	EUR (€)
Fixed Price - Natural Gas - Current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)	[1]	92
Fixed Price - Natural Gas - Non-current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)	[1]	11
Basis - Natural Gas - Current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)		194
Basis - Natural Gas - Non-current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)		607
Fixed Price - Electricity - Current Derivative Contract
Derivative [Line Items]
Volume of electricity (MWh) | MWh		13,457,158
Fixed Price - Electricity - Non-current Derivative Contract
Derivative [Line Items]
Volume of electricity (MWh) | MWh		1,537,046
Financial Transmission Rights - Electricity- Current Derivative Contract
Derivative [Line Items]
Volume of electricity (MWh) | MWh		19,361,385
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]	60,968,672
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]	280,000,000
Interest Rate - Current Derivative Contract
Derivative [Line Items]
Interest rate (US Dollars, Euros) | $	[4]	2,050,000,000
Interest Rate - Non-current Derivative Contract
Derivative [Line Items]
Interest rate (US Dollars, Euros) | $	[4]	$ 4,953,640,679
Virginia Electric and Power Company | Fixed Price - Natural Gas - Current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)	[5]	37
Virginia Electric and Power Company | Fixed Price - Natural Gas - Non-current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)	[5]	8
Virginia Electric and Power Company | Basis - Natural Gas - Current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)		74
Virginia Electric and Power Company | Basis - Natural Gas - Non-current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)		565
Virginia Electric and Power Company | Fixed Price - Electricity - Current Derivative Contract
Derivative [Line Items]
Volume of electricity (MWh) | MWh	[5]	1,580,034
Virginia Electric and Power Company | Fixed Price - Electricity - Non-current Derivative Contract
Derivative [Line Items]
Volume of electricity (MWh) | MWh	[5]	1,537,046
Virginia Electric and Power Company | Financial Transmission Rights - Electricity- Current Derivative Contract
Derivative [Line Items]
Volume of electricity (MWh) | MWh		17,668,870
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) | $	[6]	$ 1,050,000,000
Virginia Electric and Power Company | Interest Rate - Non-current Derivative Contract
Derivative [Line Items]
Interest rate (US Dollars, Euros) | $	[6]	$ 1,150,000,000
Dominion Gas Holdings, LLC | Fixed Price - Natural Gas - Current Derivative Contract
Derivative [Line Items]
Volume of derivative activity (bcf, Gal)		3
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		51,224,672
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) | $	[7]	$ 0
Dominion Gas Holdings, LLC | Foreign Exchange - Non- Current Derivative Contract
Derivative [Line Items]
Interest rate (US Dollars, Euros) | $	[7]	$ 280,000,000

[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.

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