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PROPERTY, PLANT, AND EQUIPMENT - Composite Straight-Line Rates (Details) - Utility plant in service | 12 Months Ended
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Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Alabama Power |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Composite rate | 4.10% | 2.70% | 2.70%
Georgia Power |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Composite rate | 3.80% | 3.30% | 3.30%
Mississippi Power |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Composite rate | 3.40% | 3.40% | 3.60%
Southern Company Gas |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Composite rate | 2.70% | 2.70% | 2.80%

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Composite depreciation rate for public utility plants in service. + References No definition available. + Details
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