Income Taxes - Narrative (Details)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Income Tax Contingency [Line Items]
Effective tax (benefit) rate	10.80%	14.90%
ALABAMA POWER CO
Income Tax Contingency [Line Items]
Effective tax (benefit) rate	(0.80%)	23.30%
GEORGIA POWER CO
Income Tax Contingency [Line Items]
Effective tax (benefit) rate	15.10%	7.30%
SOUTHERN POWER CO
Income Tax Contingency [Line Items]
Effective tax (benefit) rate	(20.70%)	(80.00%)