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Regulatory Matters - Schedule of Cost Recovery Clauses (Details) - USD ($) $ in Millions | Jun. 30, 2023 | Dec. 31, 2022
--- | --- | ---
Loss Contingencies [Line Items] |  |
Natural gas cost under recovery | $ 0 | $ 108
ALABAMA POWER CO | Other regulatory assets, current |  |
Loss Contingencies [Line Items] |  |
Rate CNP Compliance | 20 | 47
Rate CNP PPA | 17 | 18
Retail Energy Cost Recovery | 146 | 102
ALABAMA POWER CO | Other regulatory assets, deferred |  |
Loss Contingencies [Line Items] |  |
Rate CNP Compliance | 40 | 0
Rate CNP PPA | 95 | 102
Retail Energy Cost Recovery | 283 | 520
GEORGIA POWER CO | Receivables – under recovered fuel clause revenues |  |
Loss Contingencies [Line Items] |  |
Fuel Cost Recovery(*) | 695 | 0
GEORGIA POWER CO | Deferred under recovered fuel clause revenues |  |
Loss Contingencies [Line Items] |  |
Fuel Cost Recovery(*) | 1,489 | 2,056
MISSISSIPPI POWER CO | Other regulatory assets, current |  |
Loss Contingencies [Line Items] |  |
Ad Valorem Tax | 6 | 12
MISSISSIPPI POWER CO | Other regulatory assets, deferred |  |
Loss Contingencies [Line Items] |  |
Ad Valorem Tax | 16 | 19
MISSISSIPPI POWER CO | Receivables – customer accounts, net |  |
Loss Contingencies [Line Items] |  |
Fuel Cost Recovery(*) | 24 | 1
SOUTHERN Co GAS |  |
Loss Contingencies [Line Items] |  |
Natural gas cost under recovery | 0 | 108
SOUTHERN Co GAS | Other regulatory assets, current |  |
Loss Contingencies [Line Items] |  |
Natural gas cost under recovery | 0 | 108
SOUTHERN Co GAS | Natural gas cost over recovery |  |
Loss Contingencies [Line Items] |  |
Natural gas cost under recovery | $ 161 | $ 0

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