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Regulatory Matters (Narrative) (Detail 3) $ in Millions | 1 Months Ended | 12 Months Ended
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Feb. 23, 2024 USD ($) | Jan. 31, 2024 USD ($) | Sep. 30, 2023 USD ($) | Apr. 30, 2023 USD ($) | Mar. 31, 2023 USD ($) mi kV | Feb. 28, 2023 USD ($) | Jan. 31, 2023 USD ($) | Mar. 31, 2022 | Aug. 31, 2021 USD ($) | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($)
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Regulatory assets |  |  |  |  |  |  |  |  |  | $ 9,665 | $ 10,148 |
Impairment of assets and other charges |  |  |  |  |  |  |  |  |  | $ 307 | $ 1,401 | $ 194
South Carolina Regulation | Electric Base Rate Case |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Increase (decrease) in revenue requirement |  |  |  |  |  |  |  |  | $ 62 |  |  |
Approved return on equity percentage |  |  |  |  |  |  |  |  | 9.50% |  |  |
Public utilities, requested rate increase amortization of certain excess deferred income taxes |  |  |  |  |  |  |  |  | $ 36 |  |  |
Public utilities, retail electric customer balance |  |  |  |  |  |  |  |  | 15 |  |  |
Public utilities energy efficiency upgrades and critical health and safety repairs |  |  |  |  |  |  |  |  | $ 15 |  |  |
Regulatory assets |  |  |  |  |  |  |  |  |  |  |  | 237
South Carolina Regulation | Electric Base Rate Case | Impairment of Assets and Other Charges (Benefits) |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Impairment of assets and other charges |  |  |  |  |  |  |  |  |  |  |  | 249
Impairment of assets and other charges after tax |  |  |  |  |  |  |  |  |  |  |  | 187
South Carolina Regulation | Electric Base Rate Case | Other income (expense) |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Impairment of assets and other charges |  |  |  |  |  |  |  |  |  |  |  | 18
Impairment of assets and other charges after tax |  |  |  |  |  |  |  |  |  |  |  | $ 14
Dominion Energy South Carolina Inc | South Carolina Regulation | Electric DSM Programs |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Public energy efficiency programs cost rate adjustment approval request to recover amount |  |  |  |  |  |  | $ 46 |  |  |  |  |
Application date |  |  |  |  |  |  | 2023-01 |  |  |  |  |
Dominion Energy South Carolina Inc | South Carolina Regulation | Electric DSM Programs | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Public energy efficiency programs cost rate adjustment approval request to recover amount |  | $ 47 |  |  |  |  |  |  |  |  |  |
Application date |  | 2024-01 |  |  |  |  |  |  |  |  |  |
Dominion Energy South Carolina Inc | South Carolina Regulation | Natural Gas Base Rate Member |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Increase (decrease) in revenue requirement |  |  | $ 9 |  | $ 19 |  |  |  |  |  |  |
Percentage of proposed earned return |  |  |  |  | 10.38% |  |  |  |  |  |  |
Authorized return percentage |  |  | 9.49% |  |  |  |  | 10.25% |  |  |  |
Dominion Energy South Carolina Inc | South Carolina Regulation | Cost of Fuel |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Application date |  |  |  |  |  | 2023-02 |  |  |  |  |  |
Rate year beginning |  |  |  |  |  | 2023-05 |  |  |  |  |  |
Increase (decrease) in annual base fuel component recoveries |  |  |  |  | $ 121 | $ 176 |  |  |  |  |  |
Dominion Energy South Carolina Inc | South Carolina Regulation | Cost of Fuel | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Application date | 2024-02 |  |  |  |  |  |  |  |  |  |  |
Rate year beginning | 2024-05 |  |  |  |  |  |  |  |  |  |  |
Increase (decrease) in annual base fuel component recoveries | $ (315) |  |  |  |  |  |  |  |  |  |  |
Dominion Energy South Carolina Inc | South Carolina Regulation | Electric Transmission Project |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Application date |  |  |  |  | 2023-03 |  |  |  |  |  |  |
Cost Estimate |  |  |  |  | $ 55 |  |  |  |  |  |  |
Miles of Lines | mi |  |  |  |  | 19 |  |  |  |  |  |  |
Type of Line | kV |  |  |  |  | 230 |  |  |  |  |  |  |
Dominion Energy South Carolina Inc | South Carolina Regulation | Electric - Other |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Increase (decrease) in revenue requirement |  |  |  | $ 24 |  |  |  |  |  |  |  |

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