VARIABLE INTEREST ENTITIES AND EQUITY METHOD INVESTMENTS - Billings (Details) - Variable Interest Entity, Not Primary Beneficiary - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
AEP TEXAS INC.
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Billings from VIE	$ 242.6	$ 228.5	$ 236.8
AEP TRANSMISSION COMPANY, LLC
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Billings from VIE	289.7	269.9	286.6
APPALACHIAN POWER COMPANY
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Billings from VIE	335.3	324.9	347.5
INDIANA MICHIGAN POWER COMPANY
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Billings from VIE	187.6	178.4	192.4
OHIO POWER COMPANY
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Billings from VIE	283.4	269.5	272.5
PUBLIC SERVICE COMPANY OF OKLAHOMA
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Billings from VIE	157.4	138.6	142.3
SOUTHWESTERN ELECTRIC POWER COMPANY
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Billings from VIE	$ 194.4	$ 185.1	$ 192.5