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v3.25.3

Financing - Bank Credit Agreements Narrative (Details) - USD ($) $ in Millions | 1 Months Ended |  |
--- | --- | --- | ---
Mar. 31, 2025 | Sep. 30, 2025 | Feb. 28, 2025
Debt Instrument [Line Items] |  |  |
2030 |  | $ 7,600 |
Line of credit facility, maximum borrowing capacity |  | 8,920 |
Variable rate pollution control revenue bonds outstanding |  | 1,500 |
2027 |  | 625 |
2029 |  | 650 |
2026 |  | 45 |
Southern Company, Southern Power, And Mississippi Power |  |  |
Debt Instrument [Line Items] |  |  |
2030 |  | 3,250 |
Line of credit facility, maximum borrowing capacity | $ 3,250 |  | $ 2,450
Southern Company parent |  |  |
Debt Instrument [Line Items] |  |  |
2030 |  | 2,500 |
Line of credit facility, maximum borrowing capacity |  | 3,000 |
2028 |  |  | 150
2027 |  | 500 |
2029 |  | 0 |
2026 |  | 0 |
SOUTHERN POWER CO |  |  |
Debt Instrument [Line Items] |  |  |
2030 |  | 600 |
Line of credit facility, maximum borrowing capacity |  | 600 |
2027 |  | 0 |
2029 |  | 0 |
2026 |  | 0 |
MISSISSIPPI POWER CO |  |  |
Debt Instrument [Line Items] |  |  |
2030 |  | 150 |
Line of credit facility, maximum borrowing capacity |  | 275 |
Decrease of line of credit | 150 |  |
Variable rate pollution control revenue bonds outstanding |  | 58 |
2027 |  | 125 |
2029 |  | 0 |
2026 |  | 0 |
GEORGIA POWER CO |  |  |
Debt Instrument [Line Items] |  |  |
2030 |  | 2,050 | 1,750
Line of credit facility, maximum borrowing capacity |  | 2,050 |
Decrease of line of credit | 300 |  |
Variable rate pollution control revenue bonds outstanding |  | 667 |
Fixed rate pollution control revenue bonds outstanding |  | 384 |
2027 |  | 0 |
2029 |  | 0 |
2026 |  | 0 |
SOUTHERN Co GAS |  |  |
Debt Instrument [Line Items] |  |  |
2030 |  | 1,600 |
Line of credit facility, maximum borrowing capacity |  | 1,600 |
2027 |  | 0 |
2029 |  | 0 | $ 1,500
2026 |  | 0 |
Nicor Gas |  |  |
Debt Instrument [Line Items] |  |  |
2030 | 800 | 800 |
Decrease of line of credit | 100 |  |
ALABAMA POWER CO |  |  |
Debt Instrument [Line Items] |  |  |
2030 |  | 700 |
Line of credit facility, maximum borrowing capacity |  | 1,365 |
Variable rate pollution control revenue bonds outstanding |  | 796 |
Fixed rate pollution control revenue bonds outstanding |  | 280 |
2027 |  | 0 |
2029 |  | 650 |
2026 |  | 15 |
Southern Company Gas Capital |  |  |
Debt Instrument [Line Items] |  |  |
2030 | $ 800 | 800 |
SEGCO |  |  |
Debt Instrument [Line Items] |  |  |
2030 |  | 0 |
Line of credit facility, maximum borrowing capacity |  | 30 |
2027 |  | 0 |
2029 |  | 0 |
2026 |  | $ 30 |

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