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ASSET RETIREMENT OBLIGATIONS - Narrative (Details) - USD ($) |  |  | 1 Months Ended | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
May 01, 2024 | Aug. 01, 2023 | Nov. 30, 2024 | Sep. 30, 2024 | Nov. 30, 2023 | Sep. 30, 2023 | Jun. 30, 2023 | Dec. 31, 2024 | Dec. 31, 2022 | Dec. 31, 2019 | Feb. 14, 2024 | Dec. 31, 2023 | Mar. 06, 2023
Jointly Owned Utility Plant Interests [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Asset retirement obligations |  |  |  |  |  |  |  | $ 9,934,000,000 | $ 10,840,000,000 |  |  | $ 10,317,000,000 |
Plant Vogtle Units 3 and 4 |  |  |  |  |  |  |  |  |  |  |  |  |
Jointly Owned Utility Plant Interests [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Asset retirement obligations |  |  |  |  |  |  |  |  |  |  |  |  | $ 90,000,000
Plant Vogtle Unit 4 |  |  |  |  |  |  |  |  |  |  |  |  |
Jointly Owned Utility Plant Interests [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Asset retirement obligations |  |  |  |  |  |  |  |  |  |  | $ 118,000,000 |  |
Alabama Power |  |  |  |  |  |  |  |  |  |  |  |  |
Jointly Owned Utility Plant Interests [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Decrease to ARO |  |  |  |  |  |  | $ 15,000,000 |  |  |  |  |  |
Asset retirement obligations |  |  |  |  |  |  |  | 4,058,000,000 | 4,287,000,000 |  |  | 4,158,000,000 |
Alabama Power | Internal reserves |  |  |  |  |  |  |  |  |  |  |  |  |
Jointly Owned Utility Plant Interests [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Accumulated provisions for decommissioning |  |  |  |  |  |  |  | $ 12,000,000 |  |  |  | 13,000,000 |
Alabama Power | Plant Farley |  |  |  |  |  |  |  |  |  |  |  |  |
Jointly Owned Utility Plant Interests [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated inflation rate |  |  |  |  |  |  |  | 4.50% |  |  |  |  |
Estimated trust earnings rate |  |  |  |  |  |  |  | 7.00% |  |  |  |  |
Alabama Power | Plant Farley |  |  |  |  |  |  |  |  |  |  |  |  |
Jointly Owned Utility Plant Interests [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Site-specific estimate of decommissioning costs, period of updates made |  |  |  |  |  |  |  | 5 years |  |  |  |  |
Georgia Power |  |  |  |  |  |  |  |  |  |  |  |  |
Jointly Owned Utility Plant Interests [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Decrease to ARO |  |  | $ 60,000,000 | $ 389,000,000 | $ 210,000,000 | $ 175,000,000 |  |  |  |  |  |  |
Asset retirement obligations |  |  |  |  |  |  |  | $ 5,415,000,000 | 6,034,000,000 |  |  | 5,665,000,000 |
Georgia Power | Plant Hatch |  |  |  |  |  |  |  |  |  |  |  |  |
Jointly Owned Utility Plant Interests [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated inflation rate |  |  |  |  |  |  |  | 2.50% |  |  |  |  |
Estimated trust earnings rate |  |  |  |  |  |  |  | 4.50% |  |  |  |  |
Georgia Power | Plant Vogtle Units 3 and 4 |  |  |  |  |  |  |  |  |  |  |  |  |
Jointly Owned Utility Plant Interests [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated inflation rate |  |  |  |  |  |  |  | 2.30% |  |  |  |  |
Estimated trust earnings rate |  |  |  |  |  |  |  | 4.30% |  |  |  |  |
Georgia Power | Plant Hatch and Plant Vogtle Units 1 And 2 |  |  |  |  |  |  |  |  |  |  |  |  |
Jointly Owned Utility Plant Interests [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Annual decommissioning cost for ratemaking |  |  |  |  |  |  |  |  | 0 | $ 4,000,000 |  |  |
Georgia Power | Plant Vogtle Units 3 and 4 |  |  |  |  |  |  |  |  |  |  |  |  |
Jointly Owned Utility Plant Interests [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Annual decommissioning cost for ratemaking |  | $ 8,000,000 |  |  |  |  |  |  |  |  |  |  |
Georgia Power | Plant Vogtle Unit 4 |  |  |  |  |  |  |  |  |  |  |  |  |
Jointly Owned Utility Plant Interests [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Annual decommissioning cost for ratemaking | $ 8,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Mississippi Power |  |  |  |  |  |  |  |  |  |  |  |  |
Jointly Owned Utility Plant Interests [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Asset retirement obligations |  |  |  |  |  |  |  | $ 148,000,000 | $ 179,000,000 |  |  | $ 168,000,000 |

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