INCOME TAXES - Federal ITC/PTC Carryforwards (Details) $ in Millions	Dec. 31, 2024 USD ($)
ITC and PTC carryforwards
Operating Loss Carryforwards [Line Items]
Federal ITC/PTC carryforwards	$ 765
ITC and PTC carryforwards \| Alabama Power
Operating Loss Carryforwards [Line Items]
Federal ITC/PTC carryforwards	48
ITC and PTC carryforwards \| Georgia Power
Operating Loss Carryforwards [Line Items]
Federal ITC/PTC carryforwards	147
ITC and PTC carryforwards \| Southern Power
Operating Loss Carryforwards [Line Items]
Federal ITC/PTC carryforwards	384
Corporate Alternative Minimum Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Federal ITC/PTC carryforwards	$ 40