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REGULATORY MATTERS - GPC Nuclear Construction (Details) - Georgia Power $ in Millions |  |  | 3 Months Ended | 12 Months Ended
--- | --- | --- | --- | ---
Oct. 17, 2023 USD ($) | Oct. 05, 2023 USD ($) | Dec. 31, 2023 USD ($) | Sep. 30, 2023 USD ($) | Dec. 31, 2022 USD ($) | Dec. 31, 2023 USD ($) | Dec. 31, 2012 utility MW
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |
Number of construction units approved | utility |  |  |  |  |  |  | 2
Electric generating capacity (in MWs) | MW |  |  |  |  |  |  | 1,100
Pre-tax charge to income |  |  |  | $ 160 | $ 407 | $ 567 |
After tax charge to income |  |  |  | $ 120 | $ 304 |  |
Plant Vogtle Units 3 and 4 |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |
Percent ownership |  |  | 45.70% |  |  | 45.70% |
Estimated construction financing costs |  |  | $ 3,530 |  |  | $ 3,530 |
Construction financing costs incurred to date |  |  | 3,500 |  |  | $ 3,500 |
Pre-tax charge to income |  |  | 228 |  |  |  |
After tax charge to income |  |  | $ 170 |  |  |  |
Additional construction capital costs | $ 17 | $ 308 |  |  |  |  |
Remaining share of construction costs, agreement to pay, percentage |  | 66.00% |  |  |  | 100.00% |
Plant Vogtle Units 3 and 4 | Oglethorpe Power Corporation |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |
Agreement with third party, expected cost |  | $ 105 |  |  |  |  |
Plant Vogtle Units 3 and 4 | Dalton Utilities |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |
Agreement with third party, expected cost | $ 6 |  |  |  |  |  |
Plant Watson Unit 4 |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |
Additional base capital costs per month (up to) |  |  |  |  |  | $ 25 |

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