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FINANCING - Long-Term Debt (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022
--- | --- | ---
Debt Instrument [Line Items] |  |
Finance lease obligations | $ 298 | $ 314
Unamortized fair value adjustment | 302 | 330
Unamortized debt premium (discount), net | (198) | (193)
Unamortized debt issuance expense | (290) | (273)
Total long-term debt | 59,686 | 54,941
Less: Amount due within one year | 2,476 | 4,285
Long-Term Debt | $ 57,210 | 50,656
Senior notes |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 4.16% |
Long-term debt, gross | $ 40,235 | 35,683
Junior subordinated notes |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 4.33% |
Long-term debt, gross | $ 8,333 | 8,836
FFB loans |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 2.88% |
Long-term debt, gross | $ 4,788 | 4,874
Pollution control revenue bonds |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 3.77% |
Long-term debt, gross | $ 3,400 | 2,844
First mortgage bonds |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 3.64% |
Long-term debt, gross | $ 2,500 | 2,275
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 | 5.44% |
Long-term debt, gross | $ 234 | 167
Alabama Power |  |
Debt Instrument [Line Items] |  |
Finance lease obligations | 5 | 5
Unamortized debt premium (discount), net | (20) | (18)
Unamortized debt issuance expense | (73) | (72)
Total long-term debt | 11,183 | 10,630
Less: Amount due within one year | 223 | 301
Long-Term Debt | $ 10,960 | 10,329
Alabama Power | Senior notes |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 3.95% |
Long-term debt, gross | $ 9,875 | 9,675
Alabama Power | Pollution control revenue bonds |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 3.94% |
Long-term debt, gross | $ 1,321 | 995
Alabama Power | Other long-term debt |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 7.04% |
Long-term debt, gross | $ 75 | 45
Georgia Power |  |
Debt Instrument [Line Items] |  |
Finance lease obligations | 240 | 238
Unamortized debt premium (discount), net | (19) | (18)
Unamortized debt issuance expense | (122) | (117)
Total long-term debt | 16,700 | 14,910
Less: Amount due within one year | 502 | 901
Long-Term Debt | $ 16,198 | 14,009
Georgia Power | Senior notes |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 4.34% |
Long-term debt, gross | $ 9,575 | 7,925
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 | $ 4,788 | 4,874
Georgia Power | Pollution control revenue bonds |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 3.64% |
Long-term debt, gross | $ 1,968 | 1,738
Mississippi Power |  |
Debt Instrument [Line Items] |  |
Finance lease obligations | 16 | 17
Unamortized debt premium (discount), net | 1 | 2
Unamortized debt issuance expense | (9) | (10)
Total long-term debt | 1,644 | 1,545
Less: Amount due within one year | 201 | 1
Long-Term Debt | $ 1,443 | 1,544
Mississippi Power | Senior notes |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 4.27% |
Long-term debt, gross | $ 1,525 | 1,425
Mississippi Power | Pollution control revenue bonds |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 4.08% |
Long-term debt, gross | $ 111 | 111
Southern Power |  |
Debt Instrument [Line Items] |  |
Finance lease obligations | 0 | 0
Unamortized debt premium (discount), net | (4) | (5)
Unamortized debt issuance expense | (13) | (14)
Total long-term debt | 2,711 | 2,979
Less: Amount due within one year | 0 | 290
Long-Term Debt | 2,711 | 2,689
Fair value gain (loss) | $ (12) | (31)
Southern Power | Senior notes |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 4.05% |
Long-term debt, gross | $ 2,728 | 2,998
Southern Company Gas |  |
Debt Instrument [Line Items] |  |
Finance lease obligations | 0 | 0
Unamortized fair value adjustment | 302 | 330
Unamortized debt premium (discount), net | (8) | (8)
Unamortized debt issuance expense | (34) | (30)
Total long-term debt | 7,833 | 7,442
Less: Amount due within one year | 0 | 400
Long-Term Debt | $ 7,833 | 7,042
Southern Company Gas | Senior notes |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 4.36% |
Long-term debt, gross | $ 4,930 | 4,769
Southern Company Gas | First mortgage bonds |  |
Debt Instrument [Line Items] |  |
Weighted Average Interest Rate | 3.64% |
Long-term debt, gross | $ 2,500 | 2,275
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 | $ 59 | $ 22

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