Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Income Tax Contingency [Line Items]
Effective tax (benefit) rate		21.10%	18.50%
Unrecognized tax benefits	$ 382	$ 382		$ 82
ALABAMA POWER CO
Income Tax Contingency [Line Items]
Sale of investment tax credit		$ 44
Effective tax (benefit) rate		23.00%	21.00%
Unrecognized tax benefits	144	$ 144		0
GEORGIA POWER CO
Income Tax Contingency [Line Items]
Sale of investment tax credit		$ 28
Payment for PTCs	81
Effective tax (benefit) rate		21.70%	18.40%
Unrecognized tax benefits	$ 188	$ 188		$ 34
SOUTHERN POWER CO
Income Tax Contingency [Line Items]
Sale of investment tax credit		$ 13
Effective tax (benefit) rate		(7.00%)	(0.80%)
MISSISSIPPI POWER CO
Income Tax Contingency [Line Items]
Effective tax (benefit) rate		22.80%	18.40%
SOUTHERN Co GAS
Income Tax Contingency [Line Items]
Effective tax (benefit) rate		23.70%	25.10%