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Financing and Leases - Schedule of Credit Arrangements (Details) - USD ($) $ in Millions | Jun. 30, 2023 | May 31, 2023 | Apr. 30, 2023
--- | --- | --- | ---
Line of Credit Facility [Line Items] |  |  |
Expires, 2024 | $ 830 |  |
Expires, 2025 | 125 |  |
Expires, 2026 | 150 |  |
Expires, 2028 | 6,400 |  |
Total | 7,505 |  |
Unused | 7,466 |  |
Expires within One Year | 280 |  |
Southern Company parent(a) |  |  |
Line of Credit Facility [Line Items] |  |  |
Expires, 2024 | 150 |  |
Expires, 2025 | 0 |  |
Expires, 2026 | 0 |  |
Expires, 2028 | 1,850 | $ 1,850 |
Total | 2,000 | 150 |
Unused | 1,998 |  |
Expires within One Year | 150 |  |
ALABAMA POWER CO |  |  |
Line of Credit Facility [Line Items] |  |  |
Expires, 2024 | 550 |  |
Expires, 2025 | 0 |  |
Expires, 2026 | 0 |  |
Expires, 2028 | 700 |  |
Total | 1,250 |  |
Unused | 1,250 |  |
Expires within One Year | 0 |  |
GEORGIA POWER CO |  |  |
Line of Credit Facility [Line Items] |  |  |
Expires, 2024 | 0 |  |
Expires, 2025 | 0 |  |
Expires, 2026 | 0 |  |
Expires, 2028 | 1,750 |  |
Total | 1,750 |  |
Unused | 1,726 |  |
Expires within One Year | 0 |  |
MISSISSIPPI POWER CO |  |  |
Line of Credit Facility [Line Items] |  |  |
Expires, 2024 | 0 |  |
Expires, 2025 | 125 |  |
Expires, 2026 | 150 |  |
Expires, 2028 | 0 |  |
Total | 275 | 150 |
Unused | 275 |  |
Expires within One Year | 0 |  |
SOUTHERN POWER CO |  |  |
Line of Credit Facility [Line Items] |  |  |
Expires, 2024 | 0 |  |
Expires, 2025 | 0 |  |
Expires, 2026 | 0 |  |
Expires, 2028 | 600 | 600 |
Total | 600 |  |
Unused | 589 |  |
Expires within One Year | 0 |  |
SOUTHERN POWER CO | Continuing Letter of Credit Facility A |  |  |
Line of Credit Facility [Line Items] |  |  |
Expires, 2025 | 75 |  |
Expires, 2026 | 100 |  |
Unused | 9 |  |
SOUTHERN POWER CO | Continuing Letter of Credit Facility B |  |  |
Line of Credit Facility [Line Items] |  |  |
Unused | 16 |  |
SOUTHERN Co GAS |  |  |
Line of Credit Facility [Line Items] |  |  |
Expires, 2024 | 100 |  |
Expires, 2025 | 0 |  |
Expires, 2026 | 0 |  |
Expires, 2028 | 1,500 |  |
Total | 1,600 |  |
Unused | 1,598 |  |
Expires within One Year | 100 |  |
Expires, 2023 | 100 |  |
SEGCO |  |  |
Line of Credit Facility [Line Items] |  |  |
Expires, 2024 | 30 |  |
Expires, 2025 | 0 |  |
Expires, 2026 | 0 |  |
Expires, 2028 | 0 |  |
Total | 30 |  |
Unused | 30 |  |
Expires within One Year | 30 |  |
Southern Company and Southern Power |  |  |
Line of Credit Facility [Line Items] |  |  |
Expires, 2028 | 2,450 | 2,450 |
Southern Company Gas Capital |  |  |
Line of Credit Facility [Line Items] |  |  |
Expires, 2028 | 800 |  |
Nicor Gas |  |  |
Line of Credit Facility [Line Items] |  |  |
Expires, 2028 | $ 700 |  |
Total |  | $ 100 | $ 250

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