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Regulatory Matters - Schedule of Cost Recovery Clauses (Details) - USD ($) $ in Millions | Sep. 30, 2024 | Dec. 31, 2023
--- | --- | ---
ALABAMA POWER CO | Other regulatory assets, current |  |
Loss Contingencies [Line Items] |  |
Rate CNP Compliance | $ 0 | $ 8
Rate CNP PPA | 18 | 18
ALABAMA POWER CO | Other regulatory assets, deferred |  |
Loss Contingencies [Line Items] |  |
Rate CNP Compliance | 0 | 25
Rate CNP PPA | 70 | 85
ALABAMA POWER CO | Other regulatory liabilities, current |  |
Loss Contingencies [Line Items] |  |
Rate CNP Compliance | 4 | 0
ALABAMA POWER CO | Other regulatory liabilities, deferred |  |
Loss Contingencies [Line Items] |  |
Rate CNP Compliance | 2 | 0
ALABAMA POWER CO | Deferred under recovered retail fuel clause revenues |  |
Loss Contingencies [Line Items] |  |
Rate ECR | 10 | 246
GEORGIA POWER CO | Receivables – under recovered retail fuel clause revenues |  |
Loss Contingencies [Line Items] |  |
Fuel Cost Recovery | 683 | 694
GEORGIA POWER CO | Deferred under recovered retail fuel clause revenues |  |
Loss Contingencies [Line Items] |  |
Fuel Cost Recovery | 632 | 1,211
MISSISSIPPI POWER CO | Wholesale MB |  |
Loss Contingencies [Line Items] |  |
Fuel Cost Recovery | 0 | 0
MISSISSIPPI POWER CO | Other regulatory assets, deferred |  |
Loss Contingencies [Line Items] |  |
Ad Valorem Tax | 14 | 12
MISSISSIPPI POWER CO | Deferred under recovered retail fuel clause revenues |  |
Loss Contingencies [Line Items] |  |
Fuel Cost Recovery | 0 | 50
MISSISSIPPI POWER CO | Receivables – customer accounts, net |  |
Loss Contingencies [Line Items] |  |
Fuel Cost Recovery | 6 | 0
MISSISSIPPI POWER CO | Over recovered retail fuel clause revenues |  |
Loss Contingencies [Line Items] |  |
Fuel Cost Recovery | 0 | 27
MISSISSIPPI POWER CO | Other current liabilities | Wholesale MRA |  |
Loss Contingencies [Line Items] |  |
Fuel Cost Recovery | 16 | 5
SOUTHERN Co GAS | Natural gas cost over recovery |  |
Loss Contingencies [Line Items] |  |
Natural gas cost under recovery | $ 226 | $ 214

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