Regulatory Matters - MPC (Details) $ in Millions					1 Months Ended
	Jul. 31, 2023 USD ($)	May 02, 2023 USD ($)	Apr. 04, 2023 USD ($)	Apr. 03, 2023 USD ($)	Oct. 31, 2023 MW	Jul. 31, 2022 USD ($)
Loss Contingencies [Line Items]
Minimum annual accrual, amount				$ 8
MISSISSIPPI POWER CO
Loss Contingencies [Line Items]
Approved rate increase (decrease)			$ 12
MISSISSIPPI POWER CO | Subsequent Event
Loss Contingencies [Line Items]
Approved capacity increase (in MWs) | MW					750
MISSISSIPPI POWER CO | Ad Valorem Tax Adjustment
Loss Contingencies [Line Items]
Requested rate increase (decrease) amount		$ (7)
MISSISSIPPI POWER CO | ECO Plan
Loss Contingencies [Line Items]
Approved rate increase (decrease)			$ 3
MISSISSIPPI POWER CO | Municipal And Rural Associations Tariff
Loss Contingencies [Line Items]
Requested rate increase (decrease) amount	$ 16					$ 23
Customer refund payments	$ 6