Contingencies - Other Matters (Details) - USD ($) $ in Millions	1 Months Ended
	Aug. 31, 2022	Apr. 30, 2019
Loss Contingencies [Line Items]
Estimated additional interest expense	$ 1
ALABAMA POWER CO | AT&T
Loss Contingencies [Line Items]
Potential refund amount owed		$ 87
Refund payment period		6 years
MISSISSIPPI POWER CO
Loss Contingencies [Line Items]
Estimate of possible loss	$ 28