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)