RELATED PARTY TRANSACTIONS - Revenues (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	$ 19,969.7	$ 19,454.8	$ 19,391.7
AEP TEXAS INC.
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	2,080.8	1,906.1	1,848.0
AEP TEXAS INC. | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	5.4	4.9	3.5
AEP TRANSMISSION COMPANY, LLC
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	1,950.5	1,720.6	1,651.7
AEP TRANSMISSION COMPANY, LLC | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	1,512.3	1,317.8	1,283.8
APPALACHIAN POWER COMPANY
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	4,038.8	3,740.6	3,520.7
APPALACHIAN POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	247.4	239.3	256.1
INDIANA MICHIGAN POWER COMPANY
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	2,603.5	2,522.3	2,659.7
INDIANA MICHIGAN POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	66.2	57.8	69.6
OHIO POWER COMPANY
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	3,780.9	3,802.8	3,672.1
OHIO POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	22.7	31.1	18.8
PUBLIC SERVICE COMPANY OF OKLAHOMA
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	1,849.5	1,976.6	1,875.7
PUBLIC SERVICE COMPANY OF OKLAHOMA | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	6.9	1.2	2.9
SOUTHWESTERN ELECTRIC POWER COMPANY
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	2,043.3	2,192.1	2,283.2
SOUTHWESTERN ELECTRIC POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	62.1	46.8	53.9
Direct Sales to East Affiliates | AEP TEXAS INC. | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	0.0	0.0	0.0
Direct Sales to East Affiliates | AEP TRANSMISSION COMPANY, LLC | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	0.0	0.0	0.0
Direct Sales to East Affiliates | APPALACHIAN POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	159.0	158.7	169.7
Direct Sales to East Affiliates | INDIANA MICHIGAN POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	0.0	0.0	0.0
Direct Sales to East Affiliates | OHIO POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	0.0	0.0	0.0
Direct Sales to East Affiliates | PUBLIC SERVICE COMPANY OF OKLAHOMA | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	0.0	0.0	0.0
Direct Sales to East Affiliates | SOUTHWESTERN ELECTRIC POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	0.0	0.0	0.0
Direct Sales to West Affiliates | AEP TEXAS INC. | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers			0.0
Direct Sales to West Affiliates | AEP TRANSMISSION COMPANY, LLC | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers			0.0
Direct Sales to West Affiliates | APPALACHIAN POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers			0.0
Direct Sales to West Affiliates | INDIANA MICHIGAN POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers			0.0
Direct Sales to West Affiliates | OHIO POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers			0.0
Direct Sales to West Affiliates | PUBLIC SERVICE COMPANY OF OKLAHOMA | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers			0.0
Direct Sales to West Affiliates | SOUTHWESTERN ELECTRIC POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers			1.3
Transmission Revenues | AEP TEXAS INC. | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	0.0	0.0	0.0
Transmission Revenues | AEP TRANSMISSION COMPANY, LLC | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	1,491.1	1,304.0	1,276.4
Transmission Revenues | APPALACHIAN POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	78.8	70.9	77.5
Transmission Revenues | INDIANA MICHIGAN POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	(8.8)	(11.1)	7.7
Transmission Revenues | OHIO POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	(6.9)	3.2	(3.6)
Transmission Revenues | PUBLIC SERVICE COMPANY OF OKLAHOMA | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	0.1	0.0	0.0
Transmission Revenues | SOUTHWESTERN ELECTRIC POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	60.6	45.3	51.5
Barging, Urea Transloading and Other Transportation Services Revenues Affiliated | AEP TEXAS INC. | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers		0.0	0.0
Barging, Urea Transloading and Other Transportation Services Revenues Affiliated | AEP TRANSMISSION COMPANY, LLC | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers		0.0	0.0
Barging, Urea Transloading and Other Transportation Services Revenues Affiliated | APPALACHIAN POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers		0.0	0.0
Barging, Urea Transloading and Other Transportation Services Revenues Affiliated | INDIANA MICHIGAN POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers		59.0	54.1
Barging, Urea Transloading and Other Transportation Services Revenues Affiliated | OHIO POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers		0.0	0.0
Barging, Urea Transloading and Other Transportation Services Revenues Affiliated | PUBLIC SERVICE COMPANY OF OKLAHOMA | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers		0.0	0.0
Barging, Urea Transloading and Other Transportation Services Revenues Affiliated | SOUTHWESTERN ELECTRIC POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers		0.0	0.0
Other Revenues | AEP TEXAS INC. | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	5.4	4.9	3.5
Other Revenues | AEP TRANSMISSION COMPANY, LLC | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	21.2	13.8	7.4
Other Revenues | APPALACHIAN POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	9.6	9.7	8.9
Other Revenues | INDIANA MICHIGAN POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	75.0	9.9	7.8
Other Revenues | OHIO POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	29.6	27.9	22.4
Other Revenues | PUBLIC SERVICE COMPANY OF OKLAHOMA | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	6.8	1.2	2.9
Other Revenues | SOUTHWESTERN ELECTRIC POWER COMPANY | Affiliated Entity
Related Party Transaction [Line Items]
Total Revenues from Contracts with Customers	$ 1.5	$ 1.5	$ 1.1