Derivatives and Hedge Accounting Activities (Volume of our Derivative Activity) (Details) - 12 months ended Dec. 31, 2016 MMcf in Thousands, € in Millions		USD ($) MWh MMcf gal	EUR (€)
Fixed Price - Natural Gas - Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of derivative activity (bcf, Gal) | MMcf	[1]	91
Fixed Price - Natural Gas - Non-current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of derivative activity (bcf, Gal) | MMcf	[1]	18
Basis - Natural Gas - Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of derivative activity (bcf, Gal) | MMcf		223
Basis - Natural Gas - Non-current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of derivative activity (bcf, Gal) | MMcf		593
Fixed Price - Electricity - Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of electricity (MWh) | MWh	[1]	11,880,630
Fixed Price - Electricity - Non-current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of electricity (MWh) | MWh	[1]	1,963,426
Financial Transmission Rights - Electricity- Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of electricity (MWh) | MWh		46,269,912
Financial Transmission Rights - Electricity- Non-current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of electricity (MWh) | MWh		0
Liquids - Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of derivative activity (bcf, Gal) | gal	[2]	46,311,225
Liquids - Non-current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of derivative activity (bcf, Gal) | gal	[2]	12,741,120
Interest Rate - Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate and Foreign currency (US Dollars, Euros) | $	[3]	$ 1,800,000,000
Interest Rate - Non-current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate and Foreign currency (US Dollars, Euros) | $	[3]	2,903,640,679
Foreign currency
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate and Foreign currency (US Dollars, Euros) | €			€ 250
Foreign Exchange - Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate and Foreign currency (US Dollars, Euros) | $	[3],[4]	0
Foreign Exchange - Non- Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate and Foreign currency (US Dollars, Euros) | $	[3],[4]	$ 280,000,000
Virginia Electric and Power Company | Fixed Price - Natural Gas - Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of derivative activity (bcf, Gal) | MMcf	[5]	27
Virginia Electric and Power Company | Fixed Price - Natural Gas - Non-current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of derivative activity (bcf, Gal) | MMcf	[5]	14
Virginia Electric and Power Company | Basis - Natural Gas - Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of derivative activity (bcf, Gal) | MMcf		101
Virginia Electric and Power Company | Basis - Natural Gas - Non-current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of derivative activity (bcf, Gal) | MMcf		539
Virginia Electric and Power Company | Fixed Price - Electricity - Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of electricity (MWh) | MWh	[5]	1,343,310
Virginia Electric and Power Company | Fixed Price - Electricity - Non-current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of electricity (MWh) | MWh	[5]	1,963,426
Virginia Electric and Power Company | Financial Transmission Rights - Electricity- Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of electricity (MWh) | MWh		43,853,950
Virginia Electric and Power Company | Financial Transmission Rights - Electricity- Non-current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of electricity (MWh) | MWh		0
Virginia Electric and Power Company | Interest Rate - Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate and Foreign currency (US Dollars, Euros) | $		$ 800,000,000
Virginia Electric and Power Company | Interest Rate - Non-current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate and Foreign currency (US Dollars, Euros) | $		$ 850,000,000
Dominion Gas Holdings, LLC | Liquids - Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of derivative activity (bcf, Gal) | gal		39,549,225
Dominion Gas Holdings, LLC | Liquids - Non-current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Volume of derivative activity (bcf, Gal) | gal		7,953,120
Dominion Gas Holdings, LLC | Foreign currency
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate and Foreign currency (US Dollars, Euros) | €			€ 250
Dominion Gas Holdings, LLC | Foreign Exchange - Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate and Foreign currency (US Dollars, Euros) | $	[6]	$ 0
Dominion Gas Holdings, LLC | Foreign Exchange - Non- Current Derivative Contract
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate and Foreign currency (US Dollars, Euros) | $	[6]	$ 280,000,000

[1] Includes options.

[2] Includes NGLs and oil.

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

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

[5] Includes options.

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