Fair Value Measurements (Fair Value, Option, Quantitative Disclosures) (Details) $ in Millions		9 Months Ended
		Sep. 30, 2017 USD ($) $ / MMBTU $ / MWh		Dec. 31, 2016 USD ($)
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		$ 249	[1]	$ 279	[2]
Fair Value of Derivative Liabilities		118	[3]	155	[4]
Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets	[2]	168		194
Fair Value of Derivative Liabilities	[4]	61		31
Fair Value, Measurements, Recurring | Commodity
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		213		262
Fair Value of Derivative Liabilities		42		96
Fair Value, Measurements, Recurring | Commodity | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		168		188
Fair Value of Derivative Liabilities		6		10
Fair Value, Measurements, Recurring | Level 3
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		154
Fair Value of Derivative Liabilities		1
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		153
Fair Value of Derivative Liabilities		1
Fair Value, Measurements, Recurring | Level 3 | Commodity
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		154		147
Fair Value of Derivative Liabilities		1		8
Fair Value, Measurements, Recurring | Level 3 | Commodity | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		153		145
Fair Value of Derivative Liabilities		1		$ 2
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Commodity
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		19
Fair Value of Derivative Liabilities		1
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Commodity | Liabilities | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Liabilities		1
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Commodity | Assets | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		$ 19
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Commodity | Minimum | Liabilities
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MWh	[5]	(5)
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Commodity | Minimum | Liabilities | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MWh	[5]	(5)
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Commodity | Minimum | Assets
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MWh	[5]	(3)
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Commodity | Minimum | Assets | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MWh	[6]	(1)
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Commodity | Maximum | Liabilities
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MWh	[5]	7
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Commodity | Maximum | Liabilities | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MWh	[5]	7
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Commodity | Maximum | Assets
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MWh	[5]	7
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Commodity | Maximum | Assets | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MWh	[6]	7
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Commodity | Weighted Average | Liabilities
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MWh	[5],[7]	1
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Commodity | Weighted Average | Liabilities | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MWh	[5],[8]	1
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Commodity | Weighted Average | Assets
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MWh	[5],[7]	1
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Commodity | Weighted Average | Assets | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MWh	[6],[8]	1
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Natural Gas | Commodity
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets	[9]	$ 91
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Natural Gas | Commodity | Assets | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets	[10]	$ 91
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Natural Gas | Commodity | Minimum | Assets
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MMBTU	[5],[9]	(2)
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Natural Gas | Commodity | Minimum | Assets | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MMBTU	[6],[10]	(2)
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Natural Gas | Commodity | Maximum | Assets
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MMBTU	[5],[9]	7
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Natural Gas | Commodity | Maximum | Assets | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MMBTU	[6],[10]	7
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Natural Gas | Commodity | Weighted Average | Assets
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MMBTU	[5],[7],[9]	0
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Natural Gas | Commodity | Weighted Average | Assets | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MMBTU	[6],[8],[10]	(1)
Fair Value, Measurements, Recurring | Level 3 | Option model | Electricity | Electricity
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		$ 42
Fair Value, Measurements, Recurring | Level 3 | Option model | Electricity | Electricity | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		$ 42
Fair Value, Measurements, Recurring | Level 3 | Option model | Electricity | Electricity | Minimum | Assets
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MWh	[5]	21
Price volatility (percentage)	[11]	0.00%
Fair Value, Measurements, Recurring | Level 3 | Option model | Electricity | Electricity | Minimum | Assets | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MWh	[6]	21
Price volatility (percentage)	[12]	0.00%
Fair Value, Measurements, Recurring | Level 3 | Option model | Electricity | Electricity | Maximum | Assets
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MWh	[5]	50
Price volatility (percentage)	[11]	78.00%
Fair Value, Measurements, Recurring | Level 3 | Option model | Electricity | Electricity | Maximum | Assets | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MWh	[6]	50
Price volatility (percentage)	[12]	78.00%
Fair Value, Measurements, Recurring | Level 3 | Option model | Electricity | Electricity | Weighted Average | Assets
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MWh	[5],[7]	34
Price volatility (percentage)	[7],[11]	28.00%
Fair Value, Measurements, Recurring | Level 3 | Option model | Electricity | Electricity | Weighted Average | Assets | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MWh	[6],[8]	34
Price volatility (percentage)	[8],[12]	28.00%
Fair Value, Measurements, Recurring | Level 3 | Option model | Natural Gas | Physical options
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		$ 2
Fair Value, Measurements, Recurring | Level 3 | Option model | Natural Gas | Physical options | Assets | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		$ 1
Fair Value, Measurements, Recurring | Level 3 | Option model | Natural Gas | Physical options | Minimum | Assets
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MMBTU	[5]	2
Price volatility (percentage)	[11]	24.00%
Fair Value, Measurements, Recurring | Level 3 | Option model | Natural Gas | Physical options | Minimum | Assets | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MMBTU	[6]	2
Price volatility (percentage)	[12]	24.00%
Fair Value, Measurements, Recurring | Level 3 | Option model | Natural Gas | Physical options | Maximum | Assets
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MMBTU	[5]	7
Price volatility (percentage)	[11]	46.00%
Fair Value, Measurements, Recurring | Level 3 | Option model | Natural Gas | Physical options | Maximum | Assets | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MMBTU	[6]	7
Price volatility (percentage)	[12]	46.00%
Fair Value, Measurements, Recurring | Level 3 | Option model | Natural Gas | Physical options | Weighted Average | Assets
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MMBTU	[5],[7]	4
Price volatility (percentage)	[7],[11]	32.00%
Fair Value, Measurements, Recurring | Level 3 | Option model | Natural Gas | Physical options | Weighted Average | Assets | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Market price (per Dth, per MWh) | $ / MMBTU	[6],[8]	4
Price volatility (percentage)	[8],[12]	32.00%

[1] Noncurrent derivative assets are presented in other deferred charges and other assets in Dominion Energy’s Consolidated Balance Sheets.

[2] Noncurrent derivative assets are presented in other deferred charges and other assets in Virginia Power's Consolidated Balance Sheets.

[3] Noncurrent derivative liabilities are presented in other deferred credits and other liabilities in Dominion Energy’s Consolidated Balance Sheets.

[4] Noncurrent derivative liabilities are presented in other deferred credits and other liabilities in Virginia Power’s Consolidated Balance Sheets.

[5] Represents market prices beyond defined terms for Levels 1 and 2.

[6] Represents market prices beyond defined terms for Levels 1 and 2

[7] Averages weighted by volume.

[8] Averages weighted by volume

[9] Includes basis

[10] Includes basis.

[11] Represents volatilities unrepresented in published markets.

[12] Represents volatilities unrepresented in published markets