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Introduction - Storm Damage Reserves (Details) - USD ($) $ in Millions |  | 1 Months Ended | 9 Months Ended
--- | --- | --- | ---
Oct. 25, 2024 | Sep. 30, 2024 | Sep. 30, 2024
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] |  |  |
Balance at December 31, 2023 |  |  | $ 66
Balance at September 30, 2024 |  | $ (1,128) | (1,128)
Accrued Storm Reserve |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] |  |  |
Accrual |  |  | 45
Storm Reserve |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] |  |  |
Weather-related damages |  |  | (1,239)
ALABAMA POWER CO |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] |  |  |
Balance at December 31, 2023 |  |  | 76
Balance at September 30, 2024 |  | 53 | 53
ALABAMA POWER CO | Accrued Storm Reserve |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] |  |  |
Accrual |  |  | 10
ALABAMA POWER CO | Storm Reserve |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] |  |  |
Weather-related damages |  |  | (33)
GEORGIA POWER CO |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] |  |  |
Balance at December 31, 2023 |  |  | (54)
Weather-related damages |  | (1,100) |
Balance at September 30, 2024 |  | 1,200 | 1,200
Balance at September 30, 2024 |  | (1,231) | (1,231)
GEORGIA POWER CO | Accrued Storm Reserve |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] |  |  |
Accrual |  |  | 24
GEORGIA POWER CO | Storm Reserve |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] |  |  |
Weather-related damages |  |  | (1,201)
MISSISSIPPI POWER CO |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] |  |  |
Balance at December 31, 2023 |  |  | 44
Balance at September 30, 2024 |  | $ 50 | 50
MISSISSIPPI POWER CO | Subsequent Event |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] |  |  |
Requested rate increase (decrease) amount | $ 11 |  |
MISSISSIPPI POWER CO | Accrued Storm Reserve |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] |  |  |
Accrual |  |  | 11
MISSISSIPPI POWER CO | Storm Reserve |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] |  |  |
Weather-related damages |  |  | $ (5)

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