LEASES - Balance Sheet Information (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Lessee, Lease, Description [Line Items]
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Current Liabilities	Other Current Liabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Noncurrent	Other Liabilities, Noncurrent
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Other Current Liabilities, Other Liabilities, Noncurrent	Other Current Liabilities, Other Liabilities, Noncurrent
Net Property, Plant and Equipment Under Finance Leases	$ 163.6	$ 204.5
Obligations Under Finance Leases:
Noncurrent Liability	117.1	139.9
Liability Due Within One Year	46.5	65.7
Total Obligations Under Finance Leases	163.6	205.6
Operating Lease Assets	580.1	620.2
Obligations Under Operating Leases:
Obligations Under Operating Leases	504.3	519.4
Obligations Under Operating Leases	91.9	115.7
Total Obligations Under Operating Leases	$ 596.2	$ 635.1
AEP TEXAS INC.
Lessee, Lease, Description [Line Items]
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Current Liabilities	Other Current Liabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Noncurrent	Other Liabilities, Noncurrent
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Other Current Liabilities, Other Liabilities, Noncurrent	Other Current Liabilities, Other Liabilities, Noncurrent
Net Property, Plant and Equipment Under Finance Leases	$ 24.7	$ 27.6
Obligations Under Finance Leases:
Noncurrent Liability	18.2	20.6
Liability Due Within One Year	6.5	7.0
Total Obligations Under Finance Leases	24.7	27.6
Operating Lease Assets	54.4	77.6
Obligations Under Operating Leases:
Obligations Under Operating Leases	43.4	50.9
Obligations Under Operating Leases	13.1	28.7
Total Obligations Under Operating Leases	$ 56.5	$ 79.6
AEP TRANSMISSION COMPANY, LLC
Lessee, Lease, Description [Line Items]
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Current Liabilities	Other Current Liabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Noncurrent	Other Liabilities, Noncurrent
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Other Current Liabilities, Other Liabilities, Noncurrent	Other Current Liabilities, Other Liabilities, Noncurrent
Net Property, Plant and Equipment Under Finance Leases	$ 0.0	$ 0.0
Obligations Under Finance Leases:
Noncurrent Liability	0.0	0.0
Liability Due Within One Year	0.0	0.0
Total Obligations Under Finance Leases	0.0	0.0
Operating Lease Assets	2.3	2.6
Obligations Under Operating Leases:
Obligations Under Operating Leases	1.2	1.4
Obligations Under Operating Leases	1.3	1.3
Total Obligations Under Operating Leases	$ 2.5	$ 2.7
APPALACHIAN POWER COMPANY
Lessee, Lease, Description [Line Items]
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Current Liabilities	Other Current Liabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Noncurrent	Other Liabilities, Noncurrent
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Other Current Liabilities, Other Liabilities, Noncurrent	Other Current Liabilities, Other Liabilities, Noncurrent
Net Property, Plant and Equipment Under Finance Leases	$ 19.0	$ 26.0
Obligations Under Finance Leases:
Noncurrent Liability	11.2	17.8
Liability Due Within One Year	7.8	8.2
Total Obligations Under Finance Leases	19.0	26.0
Operating Lease Assets	67.0	73.7
Obligations Under Operating Leases:
Obligations Under Operating Leases	54.0	59.8
Obligations Under Operating Leases	13.7	14.6
Total Obligations Under Operating Leases	$ 67.7	$ 74.4
INDIANA MICHIGAN POWER COMPANY
Lessee, Lease, Description [Line Items]
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Current Liabilities	Other Current Liabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Noncurrent	Other Liabilities, Noncurrent
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Other Current Liabilities, Other Liabilities, Noncurrent	Other Current Liabilities, Other Liabilities, Noncurrent
Net Property, Plant and Equipment Under Finance Leases	$ 22.0	$ 31.5
Obligations Under Finance Leases:
Noncurrent Liability	15.9	20.8
Liability Due Within One Year	6.1	10.7
Total Obligations Under Finance Leases	22.0	31.5
Operating Lease Assets	51.5	53.8
Obligations Under Operating Leases:
Obligations Under Operating Leases	40.1	37.7
Obligations Under Operating Leases	12.3	16.8
Total Obligations Under Operating Leases	$ 52.4	$ 54.5
OHIO POWER COMPANY
Lessee, Lease, Description [Line Items]
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Current Liabilities	Other Current Liabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Noncurrent	Other Liabilities, Noncurrent
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Other Current Liabilities, Other Liabilities, Noncurrent	Other Current Liabilities, Other Liabilities, Noncurrent
Net Property, Plant and Equipment Under Finance Leases	$ 14.3	$ 18.2
Obligations Under Finance Leases:
Noncurrent Liability	10.2	13.2
Liability Due Within One Year	4.1	5.0
Total Obligations Under Finance Leases	14.3	18.2
Operating Lease Assets	60.4	69.9
Obligations Under Operating Leases:
Obligations Under Operating Leases	48.4	56.7
Obligations Under Operating Leases	12.3	13.5
Total Obligations Under Operating Leases	$ 60.7	$ 70.2
PUBLIC SERVICE COMPANY OF OKLAHOMA
Lessee, Lease, Description [Line Items]
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Current Liabilities	Other Current Liabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Noncurrent	Other Liabilities, Noncurrent
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Other Current Liabilities, Other Liabilities, Noncurrent	Other Current Liabilities, Other Liabilities, Noncurrent
Net Property, Plant and Equipment Under Finance Leases	$ 12.3	$ 13.8
Obligations Under Finance Leases:
Noncurrent Liability	9.5	10.7
Liability Due Within One Year	2.8	3.1
Total Obligations Under Finance Leases	12.3	13.8
Operating Lease Assets	106.2	112.8
Obligations Under Operating Leases:
Obligations Under Operating Leases	101.9	106.8
Obligations Under Operating Leases	10.4	10.1
Total Obligations Under Operating Leases	$ 112.3	$ 116.9
SOUTHWESTERN ELECTRIC POWER COMPANY
Lessee, Lease, Description [Line Items]
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Current Liabilities	Other Current Liabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Noncurrent	Other Liabilities, Noncurrent
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Other Current Liabilities, Other Liabilities, Noncurrent	Other Current Liabilities, Other Liabilities, Noncurrent
Net Property, Plant and Equipment Under Finance Leases	$ 18.5	$ 29.0
Obligations Under Finance Leases:
Noncurrent Liability	14.8	18.8
Liability Due Within One Year	3.7	11.3
Total Obligations Under Finance Leases	18.5	30.1
Operating Lease Assets	141.0	126.3
Obligations Under Operating Leases:
Obligations Under Operating Leases	137.5	122.5
Obligations Under Operating Leases	8.2	9.0
Total Obligations Under Operating Leases	145.7	131.5
Generation
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	73.8	120.1
Generation | AEP TEXAS INC.
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	0.0	0.0
Generation | AEP TRANSMISSION COMPANY, LLC
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	0.0	0.0
Generation | APPALACHIAN POWER COMPANY
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	41.6	41.0
Generation | INDIANA MICHIGAN POWER COMPANY
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	16.6	28.2
Generation | OHIO POWER COMPANY
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	0.0	0.0
Generation | PUBLIC SERVICE COMPANY OF OKLAHOMA
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	0.6	0.6
Generation | SOUTHWESTERN ELECTRIC POWER COMPANY
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	2.0	25.3
Other Property, Plant and Equipment
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	283.7	305.9
Other Property, Plant and Equipment | AEP TEXAS INC.
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	52.4	53.9
Other Property, Plant and Equipment | AEP TRANSMISSION COMPANY, LLC
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	0.0	0.0
Other Property, Plant and Equipment | APPALACHIAN POWER COMPANY
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	19.4	22.1
Other Property, Plant and Equipment | INDIANA MICHIGAN POWER COMPANY
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	38.8	42.3
Other Property, Plant and Equipment | OHIO POWER COMPANY
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	30.4	33.7
Other Property, Plant and Equipment | PUBLIC SERVICE COMPANY OF OKLAHOMA
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	23.0	25.5
Other Property, Plant and Equipment | SOUTHWESTERN ELECTRIC POWER COMPANY
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	29.8	32.0
Total Property, Plant and Equipment
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	357.5	426.0
Total Property, Plant and Equipment | AEP TEXAS INC.
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	52.4	53.9
Total Property, Plant and Equipment | AEP TRANSMISSION COMPANY, LLC
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	0.0	0.0
Total Property, Plant and Equipment | APPALACHIAN POWER COMPANY
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	61.0	63.1
Total Property, Plant and Equipment | INDIANA MICHIGAN POWER COMPANY
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	55.4	70.5
Total Property, Plant and Equipment | OHIO POWER COMPANY
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	30.4	33.7
Total Property, Plant and Equipment | PUBLIC SERVICE COMPANY OF OKLAHOMA
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	23.6	26.1
Total Property, Plant and Equipment | SOUTHWESTERN ELECTRIC POWER COMPANY
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	31.8	57.3
Accumulated Amortization
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	193.9	221.5
Accumulated Amortization | AEP TEXAS INC.
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	27.7	26.3
Accumulated Amortization | AEP TRANSMISSION COMPANY, LLC
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	0.0	0.0
Accumulated Amortization | APPALACHIAN POWER COMPANY
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	42.0	37.1
Accumulated Amortization | INDIANA MICHIGAN POWER COMPANY
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	33.4	39.0
Accumulated Amortization | OHIO POWER COMPANY
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	16.1	15.5
Accumulated Amortization | PUBLIC SERVICE COMPANY OF OKLAHOMA
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	11.3	12.3
Accumulated Amortization | SOUTHWESTERN ELECTRIC POWER COMPANY
Lessee, Lease, Description [Line Items]
Net Property, Plant and Equipment Under Finance Leases	$ 13.3	$ 28.3