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Acquisitions and Dispositions (Narrative) (Details) $ / shares in Units, $ in Millions |  | 1 Months Ended | 3 Months Ended | 12 Months Ended | 18 Months Ended |  |
--- | --- | --- | --- | --- | --- | --- | ---
Apr. 01, 2015 USD ($) $ / shares shares | Jan. 31, 2017 USD ($) MW | Sep. 30, 2016 MW | Aug. 31, 2016 USD ($) project MW | May 31, 2016 USD ($) | Dec. 31, 2015 USD ($) project MW | Sep. 30, 2015 USD ($) project mi MW shares | Jun. 30, 2015 USD ($) project MW | Jan. 31, 2015 USD ($) mi | Mar. 31, 2014 USD ($) | Dec. 31, 2017 USD ($) | Sep. 30, 2017 USD ($) | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) project MW | Dec. 31, 2015 USD ($) | Dec. 31, 2014 USD ($) | Dec. 31, 2016 USD ($) | Nov. 30, 2016 | Jan. 31, 2016 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Project Cost |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 40 | $ 418 | $ 206 |  |  |
Contributions from SunEdison to Four Brothers and Three Cedars |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 189 | 103 |  |  |  |
Goodwill | [1] |  |  |  |  |  | $ 3,294 |  |  |  |  |  |  |  | $ 6,399 | 3,294 | 3,044 | $ 6,399 |  |
Iroquois |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership percentage | [2] |  |  |  |  |  |  |  |  |  |  |  |  |  | 50.00% |  |  | 50.00% |  |
Merchant Solar Projects | Terra Nova Renewable Partners | Call Option |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Remaining ownership interest percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 67.00% |  |  | 67.00% |  |
Merchant Solar Projects | Disposal Group, Disposed of by Sale, Not Discontinued Operations |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
MW Capacity | MW |  |  |  |  |  |  |  | 425 |  |  |  |  |  |  |  |  |  |  |  |
SunEdison's ownership percentage interest in merchant solar projects |  |  |  |  |  |  |  | 33.00% |  |  |  |  |  |  | 33.00% |  |  | 33.00% |  |
Number of currently wholly-owned merchant solar projects | project |  |  |  |  |  |  |  | 24 |  |  |  |  |  |  |  |  |  |  |  |
Number of solar projects sold under agreement | project |  |  |  |  |  |  | 15 |  |  |  |  |  |  |  |  |  |  |  |  |
Sales price |  |  |  |  |  |  | $ 184 |  |  |  |  |  |  |  |  | 184 |  |  |  | $ 117
Electric Retail Energy Marketing Business | Disposal Group, Disposed of by Sale, Not Discontinued Operations |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration |  |  |  |  |  |  |  |  |  |  | $ 187 |  |  |  |  |  |  |  |  |
Gain on sale |  |  |  |  |  |  |  |  |  |  | 100 |  |  |  |  |  |  |  |  |
After-tax gain on sale |  |  |  |  |  |  |  |  |  |  | 57 |  |  |  |  |  |  |  |  |
Asset disposition adjustment |  |  |  |  |  |  |  |  |  |  | $ 31 |  |  |  |  |  |  |  |  |
Partnership Interest | National Grid | Iroquois |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest percentage |  |  |  |  |  |  |  | 20.40% |  |  |  |  |  |  |  |  |  |  |  |
Partnership Interest | NJNR Pipeline Company | Iroquois |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest percentage |  |  |  |  |  |  |  | 5.53% |  |  |  |  |  |  |  |  |  |  |  |
Affiliated Entity | DCG | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Dominion Midstream Partners, LP |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Sales price |  | $ 501 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest percentage |  | 100.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Affiliated Entity | DCG | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Dominion Midstream Partners, LP | Unsecured Promissory Note Receivable | Notes Receivable |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Term of senior unsecured promissory note payable |  | 2 years |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Senior unsecured promissory note payable by Dominion Midstream |  | $ 301 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (percentage) |  | 0.60% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Affiliated Entity | Partnership Interest | DCG | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Dominion Midstream Partners, LP |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of common units issued | shares |  | 5,112,139 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Value of common units at closing |  | $ 200 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of trading days |  | 10 days |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Price per unit | $ / shares |  | $ 39.12 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dominion Midstream Partners, LP | Iroquois |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership percentage | [2] |  |  |  |  |  |  |  |  |  |  |  |  |  | 25.93% |  |  | 25.93% |  |
Dominion Midstream Partners, LP | Partnership Interest | Iroquois |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
SunEdison's ownership percentage interest in merchant solar projects |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 25.93% |  |  | 25.93% |  |
Ownership percentage |  |  |  |  |  |  |  | 25.93% |  |  |  |  |  |  |  |  |  |  |  |
Length of FERC regulated interstate natural gas pipeline (in miles) (nearly 1,500 miles) | mi |  |  |  |  |  |  |  | 416 |  |  |  |  |  |  |  |  |  |  |  |
Number of common units issued | shares |  |  |  |  |  |  |  | 8,600,000 |  |  |  |  |  |  |  |  |  |  |  |
Value of common units at closing |  |  |  |  |  |  |  | $ 216 |  |  |  |  |  |  |  |  |  |  |  |
Dominion Midstream Partners, LP | Partnership Interest | National Grid | Iroquois |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of common units issued | shares |  |  |  |  |  |  |  | 6,800,000 |  |  |  |  |  |  |  |  |  |  |  |
Dominion Midstream Partners, LP | Partnership Interest | NJNR Pipeline Company | Iroquois |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of common units issued | shares |  |  |  |  |  |  |  | 1,800,000 |  |  |  |  |  |  |  |  |  |  |  |
Dominion Gas Holdings, LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Goodwill | [1] |  |  |  |  |  | $ 542 |  |  |  |  |  |  |  | $ 542 | 542 | 542 | $ 542 |  |
Dominion Gas Holdings, LLC | Iroquois |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership percentage | [2] |  |  |  |  |  |  |  |  |  |  |  |  |  | 24.07% |  |  | 24.07% |  |
Dominion Gas Holdings, LLC | Partnership Interest | Iroquois |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 24.07% |  |  | 24.07% |  |
Value of common units at closing |  |  |  |  |  | $ 7 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Project Cost |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 7 | $ 43 | $ 0 |  |  |
Individually Insignificant Solar Projects |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of equity interests acquired |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 100.00% |  |  | 100.00% |  |
Number of Projects | project |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 7 |  |  |  |  |
Purchase price |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 32 |  |  |  |  |
MW Capacity | MW |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 221 |  |  |  |  |
Number of projects that commenced operations | project | [3] |  |  |  |  |  |  |  |  |  |  |  |  |  | 1 |  |  |  |  |
Individually Insignificant Solar Projects | Scenario, Forecast |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Project Cost |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 425 |  |  |  |  |  |
Solar Projects from Solar Frontier Americas Holding, LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of equity interests acquired |  |  |  |  | 100.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of Projects | project |  |  |  |  | 2 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Purchase price |  |  |  |  | $ 128 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
MW Capacity | MW |  |  |  |  | 50 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Solar Projects from Solar Frontier Americas Holding, LLC | Scenario, Forecast |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Project Cost |  |  |  |  |  |  |  |  |  |  |  | $ 130 |  |  |  |  |  |  |  |
Solar Projects from Community Energy Solar, LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of equity interests acquired |  |  |  | 100.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
MW Capacity | MW |  |  |  | 100 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Solar Projects from Community Energy Solar, LLC | Scenario, Forecast |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Project Cost |  |  |  |  |  |  |  |  |  |  |  | $ 210 |  |  |  |  |  |  |  |
Solar Projects from Cypress Creek Renewables, LLC | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of equity interests acquired |  |  | 100.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Purchase price |  |  | $ 154 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
MW Capacity | MW |  |  | 79 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Solar Projects from Cypress Creek Renewables, LLC | Scenario, Forecast | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Project Cost |  |  |  |  |  |  |  |  |  |  |  |  | $ 160 |  |  |  |  |  |  |
Four Brothers Solar, LLC and Three Cedars |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Remaining ownership interest percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 50.00% |  |  | 50.00% |  |
Four Brothers Solar, LLC and Three Cedars | Investment Credits | Federal |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of expected federal investment tax credits on projects to be claimed |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 99.00% |  |  | 99.00% |  |
Four Brothers Solar, LLC and Three Cedars | SunEdison |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Contributions from SunEdison to Four Brothers and Three Cedars |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 292 |  |
Four Brothers Solar, LLC and Three Cedars | NRG Energy, Inc |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of equity interests acquired |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 50.00% |
Four Brothers Solar, LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of equity interests acquired |  |  |  |  |  |  |  |  | 50.00% |  |  |  |  |  |  |  |  |  |  |
Number of Projects | project |  |  |  |  |  |  |  |  | 4 |  |  |  |  |  |  |  |  |  |  |
Purchase price |  |  |  |  |  |  |  |  | $ 64 |  |  |  |  |  |  |  |  |  |  |
Project Cost |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 670 |  |  |  |  |
MW Capacity | MW |  |  |  |  |  |  |  |  | 320 |  |  |  |  |  |  |  |  |  |  |
Acquisition price payable |  |  |  |  |  |  |  |  | $ 62 |  |  |  |  |  |  |  |  |  |  |
Acquisition price in cash |  |  |  |  |  |  |  |  | 2 |  |  |  |  |  |  |  |  |  |  |
Purchase price |  |  |  |  |  |  |  |  | 64 |  |  |  |  |  |  |  |  |  |  |
Net property plant and equipment acquired |  |  |  |  |  |  |  |  | 89 |  |  |  |  |  |  |  |  |  |  |
Amount of noncontrolling interest |  |  |  |  |  |  |  |  | $ 25 |  |  |  |  |  |  |  |  |  |  |
Three Cedars |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of equity interests acquired |  |  |  |  |  |  |  | 50.00% |  |  |  |  |  |  |  |  |  |  |  |
Number of Projects | project |  |  |  |  |  |  |  | 3 |  |  |  |  |  |  |  |  |  |  |  |
Purchase price |  |  |  |  |  |  |  | $ 43 |  |  |  |  |  |  |  |  |  |  |  |
Project Cost |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 450 |  |  |  |  |
MW Capacity | MW |  |  |  |  |  |  |  | 210 |  |  |  |  |  |  |  |  |  |  |  |
Acquisition price payable |  |  |  |  |  |  |  | $ 37 |  |  |  |  |  |  |  |  |  |  |  |
Acquisition price in cash |  |  |  |  |  |  |  | 6 |  |  |  |  |  |  |  |  |  |  |  |
Purchase price |  |  |  |  |  |  |  | 43 |  |  |  |  |  |  |  |  |  |  |  |
Net property plant and equipment acquired |  |  |  |  |  |  |  | 65 |  |  |  |  |  |  |  |  |  |  |  |
Amount of noncontrolling interest |  |  |  |  |  |  |  | $ 22 |  |  |  |  |  |  |  |  |  |  |  |
Three Cedars | Current Liabilities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payable included in other current liabilities |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 2 |  |  | $ 2 |  |
DCG |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of equity interests acquired |  |  |  |  |  |  |  |  |  | 100.00% |  |  |  |  |  |  |  |  |  |
Purchase price |  |  |  |  |  |  |  |  |  | $ 497 |  |  |  |  |  |  |  |  |  |
Net property plant and equipment acquired |  |  |  |  |  |  |  |  |  | $ 277 |  |  |  |  |  |  |  |  |  |
Length of FERC regulated interstate natural gas pipeline (in miles) (nearly 1,500 miles) | mi |  |  |  |  |  |  |  |  |  | 1,500 |  |  |  |  |  |  |  |  |  |
Goodwill |  |  |  |  |  |  |  |  |  | $ 250 |  |  |  |  |  |  |  |  |  |
Amount expected to be deductible for tax purposes |  |  |  |  |  |  |  |  |  | 225 |  |  |  |  |  |  |  |  |  |
Amount of regulatory liabilities |  |  |  |  |  |  |  |  |  | $ 38 |  |  |  |  |  |  |  |  |  |
Morgans Corner Solar Energy, LLC | Virginia Electric and Power Company |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of equity interests acquired |  |  |  |  |  |  | 100.00% |  |  |  |  |  |  |  |  | 100.00% |  |  |  |
Purchase price |  |  |  |  |  |  | $ 47 |  |  |  |  |  |  |  |  |  |  |  |  |
MW Capacity | MW |  |  |  |  |  |  | 20 |  |  |  |  |  |  |  |  |  |  |  |  |
Morgans Corner Solar Energy, LLC | Virginia Electric and Power Company | Solar Development Project |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total cost of project placed into service |  |  |  |  |  |  | $ 49 |  |  |  |  |  |  |  |  | $ 49 |  |  |  |
Morgans Corner Solar Energy, LLC | Virginia Electric and Power Company | Supply Agreement with US Navy |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Duration of supply agreement |  |  |  |  |  |  | 10 years |  |  |  |  |  |  |  |  |  |  |  |  |
[1] | Goodwill amounts do not contain any accumulated impairment losses.
[2] | Comprised of Dominion Midstream's interest of 25.93% and Dominion Gas' interest of 24.07%. See Note 15 for more information.
[3] | One of the projects, Marin Carport, began commercial operations in 2016.

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