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REGULATORY MATTERS - GPC Joint Ownership Agreements (Details) - USD ($) $ in Millions |  |  |  | 1 Months Ended | 3 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | --- | ---
Oct. 17, 2023 | Oct. 05, 2023 | Sep. 29, 2022 | Sep. 30, 2022 | Dec. 31, 2023 | Sep. 30, 2023 | Dec. 31, 2022 | Dec. 31, 2023
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Agreement with third party, amount of costs over projected forecast to be paid by company |  |  | 20.00% |  |  |  |  |
Georgia Power |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Pre-tax charge to income |  |  |  |  |  | $ 160 | $ 407 | $ 567
After tax charge to income |  |  |  |  |  | $ 120 | $ 304 |
Plant Vogtle Units 3 and 4 | Georgia Power |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Ownership interest percentage required for voting for continuing construction |  |  |  |  | 90.00% |  |  | 90.00%
Production tax credits, aggregate purchase price (up to) |  |  |  |  |  |  |  | $ 300
Preliminary estimated cost to complete |  |  |  |  | $ 10,753 |  |  | $ 10,753
Additional construction capital costs | $ 17 | $ 308 |  |  |  |  |  |
Remaining share of construction costs, agreement to pay, percentage |  | 66.00% |  |  |  |  |  | 100.00%
Percentage of costs, disallowed for recovery |  |  |  |  |  |  |  | 6.00%
Costs disallowed for recovery, period |  |  |  |  |  |  |  | 6 months
Public utilities, extension project schedule, term |  |  |  |  |  |  |  | 1 year
Pre-tax charge to income |  |  |  |  | 228 |  |  |
After tax charge to income |  |  |  |  | $ 170 |  |  |
Percent ownership |  |  |  |  | 45.70% |  |  | 45.70%
Plant Vogtle Units 3 and 4 | Georgia Power | MEAG Power |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Agreement with third party, expected cost |  |  |  | $ 92 |  |  |  |
Plant Vogtle Units 3 and 4 | Georgia Power | Category I |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Preliminary estimated cost to complete |  |  |  |  | $ 8,400 |  |  | $ 8,400
Additional construction capital costs, threshold |  |  |  |  |  |  |  | 800
Plant Vogtle Units 3 and 4 | Georgia Power | Category II |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Additional construction capital costs |  |  |  |  |  |  |  | $ 80
Percentage of construction costs responsible to pay |  |  |  |  |  |  |  | 55.70%
Plant Vogtle Units 3 and 4 | Georgia Power | Category II | Vogtle Owners |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Percentage of construction costs responsible to pay |  |  |  |  |  |  |  | 44.30%
Plant Vogtle Units 3 and 4 | Georgia Power | Category II | Minimum |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Additional construction capital costs, threshold |  |  |  |  |  |  |  | $ 800
Plant Vogtle Units 3 and 4 | Georgia Power | Category II | Maximum |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Additional construction capital costs, threshold |  |  |  |  |  |  |  | 1,600
Plant Vogtle Units 3 and 4 | Georgia Power | Category III |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Additional construction capital costs |  |  |  |  |  |  |  | $ 100
Percentage of construction costs responsible to pay |  |  |  |  |  |  |  | 65.70%
Plant Vogtle Units 3 and 4 | Georgia Power | Category III | Vogtle Owners |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Percentage of construction costs responsible to pay |  |  |  |  |  |  |  | 34.30%
Plant Vogtle Units 3 and 4 | Georgia Power | Category III | Maximum |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Additional construction capital costs, threshold |  |  |  |  |  |  |  | $ 2,100

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