VARIABLE INTEREST ENTITIES AND EQUITY METHOD INVESTMENTS - Power Purchased (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
APPALACHIAN POWER COMPANY
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Amount of power purchased from OVEC	$ 133.6	$ 121.8	$ 119.3
INDIANA MICHIGAN POWER COMPANY
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Amount of power purchased from OVEC	66.8	60.9	59.7
OHIO POWER COMPANY
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Amount of power purchased from OVEC	$ 169.7	$ 154.7	$ 151.8