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FINANCING - Long-Term Debt (Details) - USD ($) $ in Millions | Dec. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Debt Instrument [Line Items] |  |
Finance lease obligations | $ 287 | $ 298
Unamortized fair value adjustment | 275 | 302
Unamortized debt premium (discount), net | (58) | (198)
Unamortized debt issuance expense | (419) | (290)
Total long-term debt | 63,486 | 59,686
Less: Amount due within one year | 4,718 | 2,476
Long-Term Debt | $ 58,768 | 57,210
Senior notes |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 4.33% |
Long-term debt, gross | $ 44,862 | 40,235
Junior subordinated notes |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 4.32% |
Long-term debt, gross | $ 7,389 | 8,333
FFB loans |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 2.88% |
Long-term debt, gross | $ 4,703 | 4,788
Pollution control revenue bonds |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 3.15% |
Long-term debt, gross | $ 3,379 | 3,400
First mortgage bonds |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 3.79% |
Long-term debt, gross | $ 2,775 | 2,500
Medium-term notes |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 7.03% |
Long-term debt, gross | $ 84 | 84
Other long-term debt |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 4.96% |
Long-term debt, gross | $ 209 | 234
Alabama Power |  |
Debt Instrument [Line Items] |  |
Finance lease obligations | 4 | 5
Unamortized debt premium (discount), net | (19) | (20)
Unamortized debt issuance expense | (67) | (73)
Total long-term debt | 11,154 | 11,183
Less: Amount due within one year | 655 | 223
Long-Term Debt | $ 10,499 | 10,960
Alabama Power | Senior notes |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 3.94% |
Long-term debt, gross | $ 9,875 | 9,875
Alabama Power | Pollution control revenue bonds |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 3.11% |
Long-term debt, gross | $ 1,300 | 1,321
Alabama Power | Other long-term debt |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 6.11% |
Long-term debt, gross | $ 61 | 75
Georgia Power |  |
Debt Instrument [Line Items] |  |
Finance lease obligations | 261 | 240
Unamortized debt premium (discount), net | (21) | (19)
Unamortized debt issuance expense | (123) | (122)
Total long-term debt | 18,350 | 16,700
Less: Amount due within one year | 966 | 502
Long-Term Debt | $ 17,384 | 16,198
Georgia Power | Senior notes |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 4.49% |
Long-term debt, gross | $ 11,292 | 9,575
Georgia Power | Junior subordinated notes |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 5.00% |
Long-term debt, gross | $ 270 | 270
Georgia Power | FFB loans |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 2.88% |
Long-term debt, gross | $ 4,703 | 4,788
Georgia Power | Pollution control revenue bonds |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 3.18% |
Long-term debt, gross | $ 1,968 | 1,968
Mississippi Power |  |
Debt Instrument [Line Items] |  |
Finance lease obligations | 14 | 16
Unamortized debt premium (discount), net | 2 | 1
Unamortized debt issuance expense | (9) | (9)
Total long-term debt | 1,693 | 1,644
Less: Amount due within one year | 12 | 201
Long-Term Debt | $ 1,681 | 1,443
Mississippi Power | Senior notes |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 4.33% |
Long-term debt, gross | $ 1,575 | 1,525
Mississippi Power | Pollution control revenue bonds |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 3.16% |
Long-term debt, gross | $ 111 | 111
Southern Power |  |
Debt Instrument [Line Items] |  |
Finance lease obligations | 0 | 0
Unamortized debt premium (discount), net | (4) | (4)
Unamortized debt issuance expense | (11) | (13)
Total long-term debt | 2,680 | 2,711
Less: Amount due within one year | 500 | 0
Long-Term Debt | 2,180 | 2,711
Fair value gain (loss) | $ (45) | (12)
Southern Power | Senior notes |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 4.05% |
Long-term debt, gross | $ 2,695 | 2,728
Southern Company Gas |  |
Debt Instrument [Line Items] |  |
Finance lease obligations | 0 | 0
Unamortized fair value adjustment | 275 | 302
Unamortized debt premium (discount), net | (9) | (8)
Unamortized debt issuance expense | (37) | (34)
Total long-term debt | 8,531 | 7,833
Less: Amount due within one year | 302 | 0
Long-Term Debt | $ 8,229 | 7,833
Southern Company Gas | Senior notes |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 4.41% |
Long-term debt, gross | $ 5,375 | 4,930
Southern Company Gas | First mortgage bonds |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 3.79% |
Long-term debt, gross | $ 2,775 | 2,500
Southern Company Gas | Medium-term notes |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 7.03% |
Long-term debt, gross | $ 84 | 84
Southern Company Gas | Other long-term debt |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 3.81% |
Long-term debt, gross | $ 68 | $ 59

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