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PROPERTY, PLANT, AND EQUIPMENT - Additional Information (Narrative) (Details) - USD ($) $ in Millions |  |  |  |  | 1 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | --- | ---
Feb. 13, 2025 | Oct. 25, 2024 | Jan. 01, 2024 | Jan. 01, 2023 | Jun. 30, 2023 | May 31, 2023 | Dec. 31, 2024 | Dec. 31, 2022 | Dec. 31, 2023
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Regulatory asset amortization period |  |  |  |  |  |  | 4 years |  |
Less: Accumulated depreciation |  |  |  |  |  |  | $ 40,126 |  | $ 37,725
Utility plant in service |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Less: Accumulated depreciation |  |  |  |  |  |  | 38,900 |  | 36,600
Other plant in service |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Less: Accumulated depreciation |  |  |  |  |  |  | $ 1,200 |  | 1,100
Maximum | Other plant in service |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Depreciation period of original cost |  |  |  |  |  |  | 40 years |  |
Alabama Power |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Requested rate increase (decrease), amount |  |  |  |  | $ 78 |  |  |  |
Less: Accumulated depreciation |  |  |  |  |  |  | $ 11,741 |  | 11,131
Georgia Power |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Requested rate increase (decrease), amount |  |  |  |  |  | $ 1,100 |  | $ 14,000 |
Less: Accumulated depreciation |  |  |  |  |  |  | 14,806 |  | 13,955
Southern Company Gas |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Requested rate increase (decrease), amount |  |  | $ 53 | $ 53 |  |  |  |  |
Less: Accumulated depreciation |  |  |  |  |  |  | 5,887 |  | 5,534
Southern Company Gas | Utility plant in service |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Less: Accumulated depreciation |  |  |  |  |  |  | 5,600 |  | 5,300
Southern Company Gas | Other plant in service |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Less: Accumulated depreciation |  |  |  |  |  |  | $ 252 |  | 210
Southern Company Gas | Maximum | Transportation equipment |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Depreciation period of original cost |  |  |  |  |  |  | 10 years |  |
Southern Company Gas | Maximum | Storage facilities |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Depreciation period of original cost |  |  |  |  |  |  | 40 years |  |
Southern Company Gas | Maximum | Other assets |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Depreciation period of original cost |  |  |  |  |  |  | 78 years |  |
Southern Company Gas | Minimum | Transportation equipment |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Depreciation period of original cost |  |  |  |  |  |  | 5 years |  |
Southern Company Gas | Minimum | Storage facilities |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Depreciation period of original cost |  |  |  |  |  |  | 5 years |  |
Mississippi Power |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Requested rate increase (decrease), amount |  | $ 11 |  |  |  |  |  |  |
Less: Accumulated depreciation |  |  |  |  |  |  | $ 1,833 |  | $ 1,792
Mississippi Power | Subsequent Event |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Requested rate increase (decrease), amount | $ 8 |  |  |  |  |  |  |  |
Mississippi Power | Chevron Products Company [Member] |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Net book value of co-generation assets |  |  |  |  |  |  | $ 139 |  |
Plant Farley | Alabama Power | Nuclear Outage |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Regulatory asset amortization period |  |  |  |  |  |  | 18 months |  |
Plant Hatch Units 1 and 2 | Georgia Power | Nuclear Outage | Maximum |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Regulatory asset amortization period |  |  |  |  |  |  | 24 months |  |
Plant Vogtle Nuclear Units One , Two, and Three | Georgia Power | Nuclear Outage |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |  |
Regulatory asset amortization period |  |  |  |  |  |  | 18 months |  |

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