FINANCING ACTIVITIES - Schedule of Long-Term Debt Maturities (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Debt Instrument [Line Items]
2026	$ 3,194
2027	2,453
2028	3,468
2029	2,887
2030	1,809
After 2030	33,896
Principal Amount	47,707
Unamortized Discount, Net and Debt Issuance Costs	(385)
Total Long-term Debt Outstanding	47,322	$ 42,643
AEP Texas
Debt Instrument [Line Items]
2026	75
2027	26
2028	526
2029	627
2030	942
After 2030	4,871
Principal Amount	7,067
Unamortized Discount, Net and Debt Issuance Costs	(51)
Total Long-term Debt Outstanding	7,016	6,442
AEPTCo
Debt Instrument [Line Items]
2026	425
2027	0
2028	559
2029	55
2030	60
After 2030	5,566
Principal Amount	6,665
Unamortized Discount, Net and Debt Issuance Costs	(66)
Total Long-term Debt Outstanding	6,599	5,768
APCo
Debt Instrument [Line Items]
2026	1,131
2027	356
2028	413
2029	0
2030	0
After 2030	4,400
Principal Amount	6,300
Unamortized Discount, Net and Debt Issuance Costs	(41)
Total Long-term Debt Outstanding	6,259	5,661
I&M
Debt Instrument [Line Items]
2026	117
2027	68
2028	388
2029	162
2030	1
After 2030	2,855
Principal Amount	3,591
Unamortized Discount, Net and Debt Issuance Costs	(30)
Total Long-term Debt Outstanding	3,561	3,494
OPCo
Debt Instrument [Line Items]
2026	0
2027	0
2028	0
2029	0
2030	350
After 2030	3,400
Principal Amount	3,750
Unamortized Discount, Net and Debt Issuance Costs	(32)
Total Long-term Debt Outstanding	3,718	3,716
PSO
Debt Instrument [Line Items]
2026	51
2027	0
2028	0
2029	100
2030	0
After 2030	3,400
Principal Amount	3,551
Unamortized Discount, Net and Debt Issuance Costs	(25)
Total Long-term Debt Outstanding	3,526	2,856
SWEPCo
Debt Instrument [Line Items]
2026	917
2027	17
2028	1,593
2029	19
2030	20
After 2030	2,434
Principal Amount	5,000
Unamortized Discount, Net and Debt Issuance Costs	(26)
Total Long-term Debt Outstanding	$ 4,974	$ 3,981