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FINANCING - Notes Payable (Details) - USD ($) $ in Millions | Dec. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Short-term Debt [Line Items] |  |
Amount Outstanding | $ 1,338 | $ 2,314
Weighted Average Interest Rate | 4.80% | 5.70%
Commercial paper |  |
Short-term Debt [Line Items] |  |
Amount Outstanding | $ 1,138 | $ 1,794
Weighted Average Interest Rate | 4.70% | 5.60%
Short-term bank debt |  |
Short-term Debt [Line Items] |  |
Amount Outstanding | $ 200 | $ 520
Weighted Average Interest Rate | 5.30% | 6.40%
Alabama Power |  |
Short-term Debt [Line Items] |  |
Amount Outstanding | $ 0 | $ 40
Alabama Power | Commercial paper |  |
Short-term Debt [Line Items] |  |
Amount Outstanding | $ 0 | $ 40
Weighted Average Interest Rate | 0.00% | 5.50%
Georgia Power |  |
Short-term Debt [Line Items] |  |
Amount Outstanding | $ 200 | $ 1,329
Weighted Average Interest Rate | 5.30% | 5.90%
Georgia Power | Commercial paper |  |
Short-term Debt [Line Items] |  |
Amount Outstanding | $ 0 | $ 809
Weighted Average Interest Rate | 0.00% | 5.60%
Georgia Power | Short-term bank debt |  |
Short-term Debt [Line Items] |  |
Amount Outstanding | $ 200 | $ 520
Weighted Average Interest Rate | 5.30% | 6.40%
Southern Power |  |
Short-term Debt [Line Items] |  |
Amount Outstanding | $ 0 | $ 138
Southern Power | Commercial paper |  |
Short-term Debt [Line Items] |  |
Amount Outstanding | $ 0 | $ 138
Weighted Average Interest Rate | 0.00% | 5.50%
Southern Company Gas |  |
Short-term Debt [Line Items] |  |
Amount Outstanding | $ 455 | $ 415
Southern Company Gas | Commercial paper |  |
Short-term Debt [Line Items] |  |
Amount Outstanding | $ 455 | $ 415
Weighted Average Interest Rate | 4.70% | 5.50%
Southern Company Gas Capital | Commercial paper |  |
Short-term Debt [Line Items] |  |
Amount Outstanding | $ 283 | $ 23
Weighted Average Interest Rate | 4.70% | 5.50%
Nicor Gas | Commercial paper |  |
Short-term Debt [Line Items] |  |
Amount Outstanding | $ 172 | $ 392
Weighted Average Interest Rate | 4.60% | 5.50%
Mississippi Power |  |
Short-term Debt [Line Items] |  |
Amount Outstanding | $ 14 | $ 0
Mississippi Power | Commercial paper |  |
Short-term Debt [Line Items] |  |
Amount Outstanding | $ 14 | $ 0
Weighted Average Interest Rate | 4.60% | 0.00%

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