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Regulatory Matters (Narrative) (Detail) $ in Millions | 1 Months Ended | 3 Months Ended | 6 Months Ended |
--- | --- | --- | --- | ---
Jul. 31, 2018 USD ($) project | Jun. 30, 2018 USD ($) kV power_station mi | May 31, 2018 USD ($) kV mi | Feb. 28, 2018 USD ($) | Oct. 31, 2017 USD ($) program | Jun. 30, 2016 | Aug. 31, 2009 kV | Apr. 30, 2008 | Apr. 30, 2007 kV | Jun. 30, 2018 USD ($) MMcf | Jun. 30, 2017 USD ($) | Jun. 30, 2018 USD ($) kV mi | Jun. 30, 2017 USD ($) | Dec. 31, 2017 USD ($)
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory assets-noncurrent |  |  | $ 2,395 |  |  |  |  |  |  |  | $ 2,395 |  | $ 2,395 |  | $ 2,480 | [1]
Cost of project |  |  |  |  |  |  |  |  |  |  |  |  | 51 | $ 280 |  |
Regulatory asset recovered through retail rates |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory assets-noncurrent | [2] |  | 237 |  |  |  |  |  |  |  | 237 |  | 237 |  | 222 |
Virginia Regulation | Operating Segments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Charge associated with legislation |  |  |  |  |  |  |  |  |  |  |  |  | 215 |  |  |
Charge associated with legislation, after tax |  |  |  |  |  |  |  |  |  |  |  |  | 160 |  |  |
Virginia Electric and Power Company |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
ROE (percentage) |  |  |  |  |  |  |  |  | 11.40% |  |  |  |  |  |  |
Regulatory assets-noncurrent |  |  | 729 |  |  |  |  |  |  |  | 729 |  | 729 |  | 810 | [3]
Interim reduction in generation and distribution services on annual basis |  |  |  | $ 125 |  |  |  |  |  |  |  |  |  |  |  |
Cost of project |  |  |  |  |  |  |  |  |  |  |  |  | 43 | $ 3 |  |
Virginia Electric and Power Company | Regulatory asset recovered through retail rates |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory assets-noncurrent | [2] |  | $ 237 |  |  |  |  |  |  |  | 237 |  | $ 237 |  | $ 222 |
Virginia Electric and Power Company | Virginia Regulation |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated recovery of fuel expenses |  |  |  | 1,500 |  |  |  |  |  |  |  |  |  |  |  |
Proposed increase in fuel revenue |  |  |  | $ 222 |  |  |  |  |  |  |  |  |  |  |  |
Earnings above authorized return on equity (basis points) |  |  |  |  |  |  |  |  |  |  |  |  | 0.70% |  |  |
One-time bill credit, provisions for current customers |  |  |  |  |  |  |  |  |  |  |  |  | $ 200 |  |  |
Virginia Electric and Power Company | Virginia Regulation | Double Circuit Transmission Line Between Near Gainesville Substation And Haymarket Substation |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capacity of transmission line (kV) | kV |  |  |  |  |  |  |  |  |  |  |  |  | 230 |  |  |
Length of kV line (miles) | mi |  |  |  |  |  |  |  |  |  |  |  |  | 5 |  |  |
Virginia Electric and Power Company | Virginia Regulation | Transmission Line Between the Chesterfield and Hopewell Substations |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capacity of transmission line (kV) | kV |  |  |  | 230 |  |  |  |  |  |  |  |  |  |  |  |
Length of kV line (miles) | mi |  |  |  | 8 |  |  |  |  |  |  |  |  |  |  |  |
Total estimated cost of project |  |  |  | $ 30 |  |  |  |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company | Virginia Regulation | Transmission Line Between the Chesterfield and Lakeside Substations |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capacity of transmission line (kV) | kV |  |  |  | 230 |  |  |  |  |  |  |  |  |  |  |  |
Length of kV line (miles) | mi |  |  |  | 21 |  |  |  |  |  |  |  |  |  |  |  |
Total estimated cost of project |  |  |  | $ 35 |  |  |  |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company | Virginia Regulation | Transmission Line Between the Landstown and Thrasher Substations |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capacity of transmission line (kV) | kV |  |  | 230 |  |  |  |  |  |  |  |  |  |  |  |  |
Length of kV line (miles) | mi |  |  | 8.5 |  |  |  |  |  |  |  |  |  |  |  |  |
Total estimated cost of project |  |  | $ 20 |  |  |  |  |  |  |  | 20 |  | $ 20 |  |  |
Virginia Electric and Power Company | Virginia Regulation | Four Separate Segments of Line # 224 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capacity of transmission line (kV) | kV |  |  | 230 |  |  |  |  |  |  |  |  |  |  |  |  |
Total estimated cost of project |  |  | $ 35 |  |  |  |  |  |  |  | 35 |  | 35 |  |  |
Virginia Electric and Power Company | Virginia Regulation | Operating Segments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Charge associated with legislation |  |  |  |  |  |  |  |  |  |  |  |  | 215 |  |  |
Charge associated with legislation, after tax |  |  |  |  |  |  |  |  |  |  |  |  | 160 |  |  |
Reduction in base rate on annual basis |  |  |  |  |  |  |  |  |  |  |  |  | 125 |  |  |
Estimated capital investment for first three years |  |  | 816 |  |  |  |  |  |  |  | 816 |  | 816 |  |  |
Proposed operations and maintenance expenses for first three years |  |  |  |  |  |  |  |  |  |  |  |  | $ 102 |  |  |
Electric distribution grid transformation project duration |  |  |  |  |  |  |  |  |  |  |  |  | 10 years |  |  |
Proposed revenue requirement |  |  |  | 755 |  |  |  |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company | Virginia Regulation | Operating Segments | Transmission Component of Virginia Power's |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proposed revenue requirement |  |  |  | 468 |  |  |  |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company | Virginia Regulation | Operating Segments | Colonial Trail West and Spring Grove 1 Solar Facilities | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cost of project |  | $ 410 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of solar facilities to be construct | project |  | 2 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company | Virginia Regulation | Rider T1 | Operating Segments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proposed revenue requirement |  |  |  | 287 |  |  |  |  |  |  |  |  |  |  |  |
Increase (decrease) in revenue requirement |  |  |  | 146 |  |  |  |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company | Virginia Regulation | Rider S | Operating Segments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proposed revenue requirement |  |  | 220 |  |  |  |  |  |  |  |  |  |  |  |  |
Increase (decrease) in revenue requirement |  |  | 2 |  |  |  |  |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company | Virginia Regulation | Rider W | Operating Segments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proposed revenue requirement |  |  | 107 |  |  |  |  |  |  |  |  |  |  |  |  |
Increase (decrease) in revenue requirement |  |  | (2) |  |  |  |  |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company | Virginia Regulation | Rider R | Operating Segments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proposed revenue requirement |  |  | 59 |  |  |  |  |  |  |  |  |  |  |  |  |
Increase (decrease) in revenue requirement |  |  | (7) |  |  |  |  |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company | Virginia Regulation | Rider B |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proposed revenue requirement |  |  |  |  | $ 54 |  |  |  |  |  |  |  |  |  |  |
Increase (decrease) in revenue requirement |  |  | $ 7 |  |  |  |  |  |  |  |  |  |  |  |  |
Number of power stations converted to biomass | power_station |  |  | 3 |  |  |  |  |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company | Virginia Regulation | Rider GV | Operating Segments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proposed revenue requirement |  |  | $ 121 |  |  |  |  |  |  |  |  |  |  |  |  |
Increase (decrease) in revenue requirement |  |  | 39 |  |  |  |  |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company | Virginia Regulation | Riders C1A and C2A | Operating Segments | Energy Efficiency Program |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proposed revenue requirement |  |  |  |  |  | $ 31 |  |  |  |  |  |  |  |  |  |
Increase (decrease) in revenue requirement |  |  |  |  |  | $ 3 |  |  |  |  |  |  |  |  |  |
Number of new energy efficiency programs | program |  |  |  |  |  | 1 |  |  |  |  |  |  |  |  |  |
Period for cost cap |  |  |  |  |  | 5 years |  |  |  |  |  |  |  |  |  |
Amount of cost recovery |  |  |  |  |  | $ 25 |  |  |  |  |  |  |  |  |  |
Approved revenue required |  |  |  | 31 |  |  |  |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company | Virginia Regulation | Rider BW | Operating Segments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proposed revenue requirement |  |  |  |  |  | 132 |  |  |  |  |  |  |  |  |  |
Increase (decrease) in revenue requirement |  |  |  |  |  | 5 |  |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company | Virginia Regulation | Rider BW | Operating Segments | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Approved revenue required |  | $ 116 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company | Virginia Regulation | Rider US-2 | Operating Segments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proposed revenue requirement |  |  |  |  |  | 15 |  |  |  |  |  |  |  |  |  |
Increase (decrease) in revenue requirement |  |  |  |  |  | $ 5 |  |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company | Virginia Regulation | Rider US-2 | Operating Segments | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Approved revenue required |  | 13 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company | Virginia Regulation | Rider US-3 | Operating Segments | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proposed revenue requirement |  | $ 11 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company | Settled Litigation | Federal Energy Regulatory Commission | Order Regarding Transmission Rate Design For Allocation Of Costs Among P J M Interconnect L L C Transmission Customers | Unfavorable Regulatory Action |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Duration of payment under settlement agreement |  |  |  |  |  |  | 10 years |  |  |  |  |  |  |  |  |
Virginia Electric and Power Company | Settled Litigation | Federal Energy Regulatory Commission | Order Regarding Transmission Rate Design For Allocation Of Costs Among P J M Interconnect L L C Transmission Customers | Unfavorable Regulatory Action | Other Current Liabilities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Amount of contingent liability |  |  | 148 |  |  |  |  |  |  |  | 148 |  | $ 148 |  |  |
Virginia Electric and Power Company | Settled Litigation | Federal Energy Regulatory Commission | Order Regarding Transmission Rate Design For Allocation Of Costs Among P J M Interconnect L L C Transmission Customers | Unfavorable Regulatory Action | Other Deferred Credits and Other Liabilities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Amount of contingent liability |  |  | 98 |  |  |  |  |  |  |  | 98 |  | 98 |  |  |
Virginia Electric and Power Company | Settled Litigation | Federal Energy Regulatory Commission | Order Regarding Transmission Rate Design For Allocation Of Costs Among P J M Interconnect L L C Transmission Customers | Unfavorable Regulatory Action | Regulatory asset recovered through retail rates |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory assets-noncurrent |  |  | $ 237 |  |  |  |  |  |  |  | 237 |  | $ 237 |  |  |
Virginia Electric and Power Company | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Facility operating capacity (kV) | kV |  |  |  |  |  |  |  |  |  | 500 |  |  |  |  |  |
Virginia Electric and Power Company | Minimum | Judicial Ruling [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Facility operating capacity (kV) | kV |  |  |  |  |  |  |  | 500 |  |  |  |  |  |  |  |
DETI | Federal Energy Regulatory Commission | Other operations and maintenance | Preliminary recommendation one |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Audit compliance charge recognized in connection with preliminary recommendation |  |  |  |  |  |  |  |  |  |  |  | $ 15 |  |  |  |
Audit compliance after-tax charge recognized in connection with preliminary recommendation |  |  |  |  |  |  |  |  |  |  |  | $ 9 |  |  |  |
DETI | Federal Energy Regulatory Commission | Other operations and maintenance | Other preliminary recommendation |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Audit compliance charge recognized in connection with preliminary recommendation |  |  |  |  |  |  |  |  |  |  | 129 |  |  |  |  |
Audit compliance after-tax charge recognized in connection with preliminary recommendation |  |  |  |  |  |  |  |  |  |  | $ 94 |  |  |  |  |
Questar Gas | Cost-of-service impact of 2017 Tax Reform Act |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reduction in regulatory liabilities |  |  |  | 15 |  |  |  |  |  |  |  |  |  |  |  |
Questar Gas | Utah and Wyoming Regulation |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
LNG peaking storage facility, liquefaction rate per day | MMcf |  |  |  |  |  |  |  |  |  |  | 8.2 |  |  |  |  |
Number of days to make prudency determination |  |  |  |  |  |  |  |  |  |  | 180 days |  |  |  |  |
Proposed cost increase (decrease) amount |  |  |  | 86 |  |  |  |  |  |  |  |  |  |  |  |
East Ohio | Ohio Regulation | Percentage of Income Payment Plan Rider |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Refund of over-recovery of accumulated arrearages |  |  |  | 4 |  |  |  |  |  |  |  |  |  |  |  |
Recovery of projected deferred program costs |  |  |  | 10 |  |  |  |  |  |  |  |  |  |  |  |
East Ohio | Ohio Regulation | UEX Rider |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Elimination of over-recovered balance of accumulated bad debt expense |  |  |  | 11 |  |  |  |  |  |  |  |  |  |  |  |
Prospective bad debt expense recovered |  |  |  | 16 |  |  |  |  |  |  |  |  |  |  |  |
Hope Gas, Inc. | West Virginia Regulation | Pipeline Infrastructure Replacement Program |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Amount of cost recovery |  |  |  | 8 |  |  |  |  |  |  |  |  |  |  |  |
Projected capital investment, current year |  |  |  | 31 |  |  |  |  |  |  |  |  |  |  |  |
Projected capital investment, next year |  |  |  | 36 |  |  |  |  |  |  |  |  |  |  |  |
Projected capital investment, previous year |  |  |  | $ 28 |  |  |  |  |  |  |  |  |  |  |  |
[1] | Dominion Energy’s Consolidated Balance Sheet at December 31, 2017 has been derived from the audited Consolidated Balance Sheet at that date.
[2] | Reflects amounts related to the PJM transmission cost allocation matter. See Note 13 for more information.
[3] | Virginia Power’s Consolidated Balance Sheet at December 31, 2017 has been derived from the audited Consolidated Balance Sheet at that date.

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