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SEGMENT AND RELATED INFORMATION - Narrative (Details) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 USD ($) segment state | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($)
Segment Reporting Information [Line Items] |  |  |
Total operating revenues | $ 26,764 | $ 24,828 | $ 25,941
Total operating revenues | 26,724 | 25,253 | 29,279
Southern Power |  |  |
Segment Reporting Information [Line Items] |  |  |
Total operating revenues | 1,445 | 1,630 | 2,805
Total operating revenues | $ 2,014 | 2,189 | 3,369
Number of reportable segments | segment | 1 |  |
Southern Company Gas |  |  |
Segment Reporting Information [Line Items] |  |  |
Total operating revenues | $ 4,340 | 4,598 | 5,905
Total operating revenues | $ 4,456 | 4,702 | 5,962
Number of reportable segments | segment | 3 |  |
Number of states in which entity operates | state | 4 |  |
Southern Natural Gas Company, LLC | Southern Company Gas |  |  |
Segment Reporting Information [Line Items] |  |  |
Ownership percentage, equity method investment | 50.00% |  |
Dalton Pipeline | Southern Company Gas |  |  |
Segment Reporting Information [Line Items] |  |  |
Ownership percentage, equity method investment | 50.00% |  |
Wholesale revenues, affiliates | Southern Power |  |  |
Segment Reporting Information [Line Items] |  |  |
Total operating revenues | $ 371 | $ 537 | $ 875

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