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Fair Value Measurements (Fair Value, Option, Quantitative Disclosures) (Details) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2017 USD ($) $ / MWh $ / MMBTU | Dec. 31, 2016 USD ($)
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Assets |  | $ 274 | $ 279
Fair Value of Derivative Liabilities |  | 150 | 155
Virginia Electric and Power Company |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Assets |  | 178 | 194
Fair Value of Derivative Liabilities |  | 33 | 31
Dominion Gas Holdings, LLC |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Liabilities |  | 7 | 11
Level 3 | Virginia Electric and Power Company |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Assets |  | 140 |
Fair Value, Measurements, Recurring | Physical and financial forwards and futures: |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Assets |  | 254 | 262
Fair Value of Derivative Liabilities |  | 85 | 96
Fair Value, Measurements, Recurring | Virginia Electric and Power Company | Physical and financial forwards and futures: |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Assets |  | 170 | 188
Fair Value of Derivative Liabilities |  | 11 | 10
Fair Value, Measurements, Recurring | Dominion Gas Holdings, LLC | Physical and financial forwards and futures: |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Liabilities |  | 1 | 5
Fair Value, Measurements, Recurring | Level 3 |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Assets |  | 141 |
Fair Value of Derivative Liabilities |  | 11 |
Fair Value, Measurements, Recurring | Level 3 | Physical and financial forwards and futures: |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Assets |  | 141 | 147
Fair Value of Derivative Liabilities |  | 11 | 8
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Natural Gas | Physical and financial forwards and futures: |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Assets | [1] | 78 |
Fair Value of Derivative Liabilities | [1] | $ 2 |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Natural Gas | Liabilities | Physical and financial forwards and futures: | Minimum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MMBTU | [2] | (1) |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Natural Gas | Liabilities | Physical and financial forwards and futures: | Maximum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MMBTU | [2] | 4 |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Natural Gas | Liabilities | Physical and financial forwards and futures: | Weighted Average |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MMBTU | [2],[3] | 3 |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Natural Gas | Assets | Physical and financial forwards and futures: | Minimum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MMBTU | [2] | (2) |
Credit Spreads (percentage) | [4] | 0.00% |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Natural Gas | Assets | Physical and financial forwards and futures: | Maximum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MMBTU | [2] | 7 |
Credit Spreads (percentage) | [4] | 4.00% |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Natural Gas | Assets | Physical and financial forwards and futures: | Weighted Average |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MMBTU | [2],[3] | 0 |
Credit Spreads (percentage) | [3],[5] | 2.00% |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Physical and financial forwards and futures: |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Assets |  | $ 1 |
Fair Value of Derivative Liabilities |  | $ 8 |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Liabilities | Physical and financial forwards and futures: | Minimum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MWh | [2] | (3) |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Liabilities | Physical and financial forwards and futures: | Maximum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MWh | [2] | 2 |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Liabilities | Physical and financial forwards and futures: | Weighted Average |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MWh | [2],[3] | 0 |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Assets | Physical and financial forwards and futures: | Minimum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MWh | [2] | (3) |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Assets | Physical and financial forwards and futures: | Maximum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MWh | [2] | 3 |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | FTRs | Assets | Physical and financial forwards and futures: | Weighted Average |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MWh | [2],[3] | 0 |
Fair Value, Measurements, Recurring | Level 3 | Option model | Natural Gas | Physical and financial options: |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Assets |  | $ 2 |
Fair Value of Derivative Liabilities |  | $ 1 |
Fair Value, Measurements, Recurring | Level 3 | Option model | Natural Gas | Liabilities | Physical and financial options: | Minimum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MMBTU | [2] | 2 |
Price volatility (percentage) | [6] | 34.00% |
Fair Value, Measurements, Recurring | Level 3 | Option model | Natural Gas | Liabilities | Physical and financial options: | Maximum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MMBTU | [2] | 3 |
Price volatility (percentage) | [6] | 48.00% |
Fair Value, Measurements, Recurring | Level 3 | Option model | Natural Gas | Liabilities | Physical and financial options: | Weighted Average |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MMBTU | [2],[3] | 3 |
Price volatility (percentage) | [3],[6] | 39.00% |
Fair Value, Measurements, Recurring | Level 3 | Option model | Natural Gas | Assets | Physical and financial options: | Minimum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MMBTU | [2] | 2 |
Price volatility (percentage) | [6] | 18.00% |
Fair Value, Measurements, Recurring | Level 3 | Option model | Natural Gas | Assets | Physical and financial options: | Maximum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MMBTU | [2] | 7 |
Price volatility (percentage) | [6] | 48.00% |
Fair Value, Measurements, Recurring | Level 3 | Option model | Natural Gas | Assets | Physical and financial options: | Weighted Average |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MMBTU | [2],[3] | 3 |
Price volatility (percentage) | [3],[6] | 25.00% |
Fair Value, Measurements, Recurring | Level 3 | Option model | Electricity | Electricity |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Assets |  | $ 60 |
Fair Value, Measurements, Recurring | Level 3 | Option model | Electricity | Assets | Electricity | Minimum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MWh | [7] | 21 |
Price volatility (percentage) | [8] | 14.00% |
Fair Value, Measurements, Recurring | Level 3 | Option model | Electricity | Assets | Electricity | Maximum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MWh | [7] | 54 |
Price volatility (percentage) | [8] | 68.00% |
Fair Value, Measurements, Recurring | Level 3 | Option model | Electricity | Assets | Electricity | Weighted Average |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MWh | [2],[3] | 33 |
Price volatility (percentage) | [3],[6] | 31.00% |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Liabilities |  | $ 8 |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | Physical and financial forwards and futures: |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Assets |  | 140 | 145
Fair Value of Derivative Liabilities |  | 8 | 2
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | Discounted cash flow | Natural Gas | Physical and financial forwards and futures: |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Assets | [9] | $ 77 |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | Discounted cash flow | Natural Gas | Assets | Physical and financial forwards and futures: | Minimum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MMBTU | [7] | (2) |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | Discounted cash flow | Natural Gas | Assets | Physical and financial forwards and futures: | Maximum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MMBTU | [7] | 7 |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | Discounted cash flow | Natural Gas | Assets | Physical and financial forwards and futures: | Weighted Average |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MMBTU | [7],[10] | 0 |
Credit Spreads (percentage) | [4],[10] | 2.00% |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | Discounted cash flow | FTRs | Physical and financial forwards and futures: |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Assets |  | $ 1 |
Fair Value of Derivative Liabilities |  | $ 8 |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | Discounted cash flow | FTRs | Liabilities | Physical and financial forwards and futures: | Minimum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MWh | [7] | (3) |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | Discounted cash flow | FTRs | Liabilities | Physical and financial forwards and futures: | Maximum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MWh | [7] | 2 |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | Discounted cash flow | FTRs | Liabilities | Physical and financial forwards and futures: | Weighted Average |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MWh | [7],[10] | 0 |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | Discounted cash flow | FTRs | Assets | Physical and financial forwards and futures: | Minimum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MWh | [7] | (3) |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | Discounted cash flow | FTRs | Assets | Physical and financial forwards and futures: | Maximum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MWh | [7] | 2 |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | Discounted cash flow | FTRs | Assets | Physical and financial forwards and futures: | Weighted Average |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MWh | [7],[10] | 0 |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | Option model | Natural Gas | Physical and financial options: |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Assets |  | $ 2 |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | Option model | Natural Gas | Assets | Physical and financial options: | Minimum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MMBTU | [7] | 2 |
Price volatility (percentage) | [8] | 18.00% |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | Option model | Natural Gas | Assets | Physical and financial options: | Maximum |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MMBTU | [7] | 7 |
Price volatility (percentage) | [8] | 40.00% |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | Option model | Natural Gas | Assets | Physical and financial options: | Weighted Average |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MMBTU | [7],[10] | 3 |
Price volatility (percentage) | [8],[10] | 25.00% |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | Option model | Electricity | Electricity |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Assets |  | $ 60 |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | Option model | Electricity | Assets | Electricity | Weighted Average |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Market price (per Dth, per MWh) | $ / MWh | [7],[10] | 33 |
Price volatility (percentage) | [8],[10] | 31.00% |
Fair Value, Measurements, Recurring | Level 3 | Dominion Gas Holdings, LLC | Physical and financial forwards and futures: |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |
Fair Value of Derivative Liabilities |  | $ 0 | $ 2
[1] | Includes basis.
[2] | Represents market prices beyond defined terms for Levels 1 and 2.
[3] | Averages weighted by volume.
[4] | Represents credit spreads unrepresented in published markets.
[5] | Represents credit spreads unrepresented in published markets.
[6] | Represents volatilities unrepresented in published markets.
[7] | Represents market prices beyond defined terms for Levels 1 and 2.
[8] | Represents volatilities unrepresented in published markets.
[9] | Includes basis.
[10] | Averages weighted by volume.

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- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13433-108611 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13495-108611 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=51825145&loc=SL20226008-175313 + Details
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