REGULATORY MATTERS - MPC Municipal and Rural Associations Tariff (Details) - Mississippi Power $ in Millions		1 Months Ended
	Jul. 31, 2023 USD ($)	Jul. 31, 2022 USD ($)	Dec. 31, 2023 MW	Dec. 31, 2022	Aug. 26, 2022
Municipal and Rural Associations Tariff
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount	$ 16	$ 23
Refund to customers	$ 6
Cooperative Energy
Public Utilities, General Disclosures [Line Items]
Counterparty's option to decrease services, percentage				2.50%
Power being supplied to counterparty | MW			390
Counterparty's electricity requirement at MRA delivery points					100.00%