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ACQUISITIONS AND DISPOSITIONS - Southern Power Narrative (Details) - SOUTHERN POWER CO - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Asset Acquisition [Line Items]
Gain on dispositions, net	$ 20	$ 2	$ 41
South Cheyenne Solar Facility and Millers Branch Solar Development
Asset Acquisition [Line Items]
Payments to acquire businesses	193
Wind Generating Facility
Asset Acquisition [Line Items]
Gain on dispositions, net	$ 37		$ 37