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CONTINGENCIES, COMMITMENTS, AND GUARANTEES - MPC Other Matters (Details)		12 Months Ended					60 Months Ended
	Aug. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2025 USD ($)	Jan. 15, 2024 USD ($)	Jul. 12, 2022 claim	Dec. 31, 2016 USD ($)	Dec. 31, 2010 USD ($)
Loss Contingencies [Line Items]
Period costs		$ 36,000,000	$ 26,000,000
Mississippi Power
Loss Contingencies [Line Items]
Period costs		0	0
Estimate of possible loss	$ 28,000,000
Kemper County energy facility assets, net | Mississippi Power
Loss Contingencies [Line Items]
Pre-tax charge to income		15,000,000	11,000,000	$ 4,000,000
After tax charge to income		$ 12,000,000	$ 8,000,000	$ 3,000,000
Government grants expected										$ 137,000,000	$ 270,000,000
Government grants received						$ 387,000,000
Plant Daniel | Mississippi Power
Loss Contingencies [Line Items]
Plant units | claim									2
Plant Daniel Unit, Primary | Mississippi Power
Loss Contingencies [Line Items]
Plant units | claim									1
Scenario, Forecast | Kemper County energy facility assets, net | Mississippi Power | Maximum
Loss Contingencies [Line Items]
Period costs							$ 15,000,000
Scenario, Forecast | Plant Daniel | Mississippi Power
Loss Contingencies [Line Items]
Payments to acquire businesses								$ 1
Business combination, option to purchase, period								120 days
Scenario, Forecast | Plant Daniel | Gulf Power
Loss Contingencies [Line Items]
Percent ownership in individual unit								100.00%
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Gulf Power
Loss Contingencies [Line Items]
Proceeds from divestiture of businesses, amount held back					$ 75,000,000

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