Fair Value Measurements (Fair Value, Option, Quantitative Disclosures) (Details) $ in Millions		6 Months Ended
		Jun. 30, 2017 USD ($) $ / MMBTU $ / MWh		Dec. 31, 2016 USD ($)
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		$ 281	[1]	$ 279	[2]
Fair Value of Derivative Liabilities		150	[3]	155	[4]
Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets	[2]	167		194
Fair Value of Derivative Liabilities	[4]	74		31
Fair Value, Measurements, Recurring | Commodity
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		252		262
Fair Value of Derivative Liabilities		61		96
Fair Value, Measurements, Recurring | Commodity | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		167		188
Fair Value of Derivative Liabilities		10		10
Fair Value, Measurements, Recurring | Level 3
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 | Virginia Electric and Power Company
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		152
Fair Value, Measurements, Recurring | Level 3 | Commodity
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		153		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		152		145
Fair Value of Derivative Liabilities		0		$ 2
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Natural Gas | Commodity
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets	[5]	88
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	[6]	$ 88
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],[7]	(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],[8]	(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],[7]	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],[8]	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]	0
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Commodity
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		$ 16
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		$ 15
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	[7]	(2)
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	[7]	(1)
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	[8]	(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	[7]	4
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	[7]	4
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	[8]	4
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	[7],[9]	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	[7],[9]	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	[8],[10]	1
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		$ 2
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	[7]	2
Price volatility (percentage)	[11]	17.00%
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	[8]	2
Price volatility (percentage)	[12]	17.00%
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	[7]	7
Price volatility (percentage)	[11]	43.00%
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	[8]	7
Price volatility (percentage)	[12]	43.00%
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	[7],[9]	3
Price volatility (percentage)	[9],[11]	25.00%
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	[8],[10]	3
Price volatility (percentage)	[10],[12]	24.00%
Fair Value, Measurements, Recurring | Level 3 | Option model | Electricity | Electricity
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value of Derivative Assets		$ 47
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		$ 47
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	[7]	21
Price volatility (percentage)	[11]	14.00%
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	[8]	21
Price volatility (percentage)	[12]	14.00%
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	[7]	51
Price volatility (percentage)	[11]	57.00%
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	[8]	51
Price volatility (percentage)	[12]	57.00%
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	[7],[9]	32
Price volatility (percentage)	[9],[11]	25.00%
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	[8],[10]	32
Price volatility (percentage)	[10],[12]	25.00%

[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] Includes basis

[6] Includes basis.

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

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

[9] Averages weighted by volume.

[10] Averages weighted by volume

[11] Represents volatilities unrepresented in published markets.

[12] Represents volatilities unrepresented in published markets