Financing and Leases - Narrative (Details) $ in Millions	Mar. 31, 2023 USD ($)
Debt Instrument [Line Items]
Variable rate pollution control revenue bonds outstanding	$ 1,700
MISSISSIPPI POWER CO
Debt Instrument [Line Items]
Variable rate pollution control revenue bonds outstanding	69
ALABAMA POWER CO
Debt Instrument [Line Items]
Variable rate pollution control revenue bonds outstanding	789
Fixed rate pollution control revenue bonds outstanding	120
GEORGIA POWER CO
Debt Instrument [Line Items]
Variable rate pollution control revenue bonds outstanding	819
Fixed rate pollution control revenue bonds outstanding	$ 285