LEASES - Future Minimum Lease Payments (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Finance Leases
2025	$ 55.6
2026	39.8
2027	30.5
2028	23.1
2029	15.5
After 2029	26.4
Total Future Minimum Lease Payments	190.9
Less: Imputed Interest	27.3
Estimated Present Value of Future Minimum Lease Payments	163.6	$ 205.6
Operating Leases
2025	123.0
2026	107.8
2027	94.0
2028	78.5
2029	52.3
After 2029	340.0
Total Future Minimum Lease Payments	795.6
Less: Imputed Interest	199.4
Estimated Present Value of Future Minimum Lease Payments	596.2	635.1
AEP TEXAS INC.
Finance Leases
2025	7.8
2026	6.2
2027	4.5
2028	3.1
2029	2.4
After 2029	4.7
Total Future Minimum Lease Payments	28.7
Less: Imputed Interest	4.0
Estimated Present Value of Future Minimum Lease Payments	24.7	27.6
Operating Leases
2025	16.7
2026	14.5
2027	11.9
2028	8.9
2029	4.9
After 2029	6.5
Total Future Minimum Lease Payments	63.4
Less: Imputed Interest	6.9
Estimated Present Value of Future Minimum Lease Payments	56.5	79.6
AEP TRANSMISSION COMPANY, LLC
Finance Leases
2025	0.0
2026	0.0
2027	0.0
2028	0.0
2029	0.0
After 2029	0.0
Total Future Minimum Lease Payments	0.0
Less: Imputed Interest	0.0
Estimated Present Value of Future Minimum Lease Payments	0.0	0.0
Operating Leases
2025	1.3
2026	0.7
2027	0.3
2028	0.3
2029	0.0
After 2029	0.0
Total Future Minimum Lease Payments	2.6
Less: Imputed Interest	0.1
Estimated Present Value of Future Minimum Lease Payments	2.5	2.7
APPALACHIAN POWER COMPANY
Finance Leases
2025	8.9
2026	4.0
2027	2.5
2028	2.0
2029	1.6
After 2029	2.5
Total Future Minimum Lease Payments	21.5
Less: Imputed Interest	2.5
Estimated Present Value of Future Minimum Lease Payments	19.0	26.0
Operating Leases
2025	17.3
2026	15.3
2027	13.6
2028	11.4
2029	8.2
After 2029	10.2
Total Future Minimum Lease Payments	76.0
Less: Imputed Interest	8.3
Estimated Present Value of Future Minimum Lease Payments	67.7	74.4
INDIANA MICHIGAN POWER COMPANY
Finance Leases
2025	7.7
2026	4.9
2027	4.1
2028	3.4
2029	2.8
After 2029	4.7
Total Future Minimum Lease Payments	27.6
Less: Imputed Interest	5.6
Estimated Present Value of Future Minimum Lease Payments	22.0	31.5
Operating Leases
2025	15.9
2026	15.0
2027	11.0
2028	9.0
2029	4.4
After 2029	2.4
Total Future Minimum Lease Payments	57.7
Less: Imputed Interest	5.3
Estimated Present Value of Future Minimum Lease Payments	52.4	54.5
OHIO POWER COMPANY
Finance Leases
2025	4.8
2026	3.6
2027	2.6
2028	2.0
2029	1.4
After 2029	1.9
Total Future Minimum Lease Payments	16.3
Less: Imputed Interest	2.0
Estimated Present Value of Future Minimum Lease Payments	14.3	18.2
Operating Leases
2025	16.3
2026	15.1
2027	13.5
2028	11.3
2029	6.6
After 2029	4.9
Total Future Minimum Lease Payments	67.7
Less: Imputed Interest	7.0
Estimated Present Value of Future Minimum Lease Payments	60.7	70.2
PUBLIC SERVICE COMPANY OF OKLAHOMA
Finance Leases
2025	3.4
2026	2.9
2027	2.3
2028	1.8
2029	1.3
After 2029	2.6
Total Future Minimum Lease Payments	14.3
Less: Imputed Interest	2.0
Estimated Present Value of Future Minimum Lease Payments	12.3	13.8
Operating Leases
2025	11.6
2026	10.8
2027	9.8
2028	8.4
2029	6.5
After 2029	123.7
Total Future Minimum Lease Payments	170.8
Less: Imputed Interest	58.5
Estimated Present Value of Future Minimum Lease Payments	112.3	116.9
SOUTHWESTERN ELECTRIC POWER COMPANY
Finance Leases
2025	4.7
2026	4.0
2027	3.3
2028	2.7
2029	2.4
After 2029	5.0
Total Future Minimum Lease Payments	22.1
Less: Imputed Interest	3.6
Estimated Present Value of Future Minimum Lease Payments	18.5	30.1
Operating Leases
2025	17.6
2026	15.5
2027	14.1
2028	12.1
2029	9.0
After 2029	178.1
Total Future Minimum Lease Payments	246.4
Less: Imputed Interest	100.7
Estimated Present Value of Future Minimum Lease Payments	$ 145.7	$ 131.5