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REGULATORY MATTERS - GPC Regulatory Matters (Details) - Georgia Power $ in Millions |  |  |  |  |  |  | 6 Months Ended | 12 Months Ended |  |
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Nov. 18, 2021 USD ($) | Jan. 01, 2021 | Jan. 01, 2020 | Jan. 11, 2018 USD ($) | Jan. 01, 2018 | Jan. 01, 2016 | Jun. 30, 2021 USD ($) report | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) | Dec. 31, 2015 USD ($) | Dec. 31, 2009 USD ($) | Jun. 30, 2018 USD ($) | Dec. 31, 2013
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Retail rate of return on common equity |  |  |  |  |  |  |  |  |  |  |  | 10.50% |  |  |  | 10.95%
Plant Vogtle Units 3 and 4 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated in-service capital cost |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 4,418 |  |
Proceeds from recovery of financing costs |  |  |  |  |  |  |  |  |  | $ 2,700 |  |  |  |  |  |
Project capital cost forecast |  |  |  | $ 7,300 |  |  |  |  |  |  |  |  |  |  |  |
Requested decrease in NCCR tariff | $ 78 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Additional construction capital costs |  |  |  |  |  |  |  |  |  | $ 460 |  |  | $ 3,300 |  |  |
Payments for contractor settlement agreement |  |  |  | 300 |  |  |  |  |  |  |  |  |  |  |  |
Amendment to estimated in-service capital cost |  |  |  | $ 5,680 |  |  |  |  |  |  |  |  |  |  |  |
Retail rate of return on common equity |  |  |  |  |  |  |  |  |  |  |  |  | 10.95% |  |  |
Authorized ROE |  | 5.30% | 8.30% |  | 10.00% | 10.00% |  |  |  |  |  |  |  |  |  |
Potential decrease each month, percentage |  |  |  |  |  |  |  |  |  | 0.10% |  |  |  |  |  |
Return on equity reduction, negative impact on earnings |  |  |  |  |  |  |  |  |  | $ 270 | $ 150 | $ 75 |  |  |  |
Increase to base capital cost forecast not seeking recovery |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 700 |
Plant Vogtle Units 3 and 4 | Twenty Fifth Vogtle Construction Monitoring Report |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of approved construction monitoring reports | report |  |  |  |  |  |  | 24 |  |  |  |  |  |  |  |  |
Approval of construction capital costs |  |  |  |  |  |  | $ 7,300 |  |  |  |  |  |  |  |  |
Maximum guarantee |  |  |  |  |  |  | 1,700 |  |  |  |  |  |  |  |  |
Customer refund |  |  |  |  |  |  | $ 188 |  |  |  |  |  |  |  |  |
Plant Vogtle Units 3 and 4 | Scenario, Forecast |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Return on equity reduction, negative impact on earnings |  |  |  |  |  |  |  | $ 265 | $ 300 |  |  |  |  |  |  |

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