DERIVATIVES AND HEDGING - Schedule of Gain (Loss) Recognized on Risk Management Contracts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	$ 478	$ 151	$ (323)
Regulatory Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	(16)	73	(95)
Regulatory Liabilities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	394	271	170
Revenues | Vertically Integrated Utilities Revenues
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	(9)	(24)	25
Revenues | Generation & Marketing
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	102	(172)	(424)
Revenues | Electric Generation, Transmission and Distribution Revenues
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	7	3	3
Other Operation
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts			(1)
Maintenance
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts			(1)
AEP Texas
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	(1)
AEP Texas | Regulatory Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
AEP Texas | Regulatory Liabilities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
AEP Texas | Revenues | Vertically Integrated Utilities Revenues
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
AEP Texas | Revenues | Generation & Marketing
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
AEP Texas | Revenues | Electric Generation, Transmission and Distribution Revenues
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
AEP Texas | Purchased Electricity, Fuel and Other Consumables Used for Electric Generation
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
AEP Texas | Other Operation
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts			0
AEP Texas | Maintenance
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts			(1)
APCo
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	131	78	(19)
APCo | Regulatory Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	22	(22)
APCo | Regulatory Liabilities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	124	53	1
APCo | Revenues | Vertically Integrated Utilities Revenues
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
APCo | Revenues | Generation & Marketing
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
APCo | Revenues | Electric Generation, Transmission and Distribution Revenues
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
APCo | Purchased Electricity, Fuel and Other Consumables Used for Electric Generation
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	7	3	2
APCo | Other Operation
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts			0
APCo | Maintenance
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts			0
I&M
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	18	(8)	29
I&M | Regulatory Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	3	(3)
I&M | Regulatory Liabilities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	28	13	8
I&M | Revenues | Vertically Integrated Utilities Revenues
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
I&M | Revenues | Generation & Marketing
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
I&M | Revenues | Electric Generation, Transmission and Distribution Revenues
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	(10)	(24)	24
I&M | Purchased Electricity, Fuel and Other Consumables Used for Electric Generation
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
I&M | Other Operation
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts			0
I&M | Maintenance
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts			0
OPCo
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	16	(2)	(14)
OPCo | Regulatory Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	15	(2)	(14)
OPCo | Regulatory Liabilities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	1	0	0
OPCo | Revenues | Vertically Integrated Utilities Revenues
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
OPCo | Revenues | Generation & Marketing
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
OPCo | Revenues | Electric Generation, Transmission and Distribution Revenues
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
OPCo | Purchased Electricity, Fuel and Other Consumables Used for Electric Generation
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
OPCo | Other Operation
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts			0
OPCo | Maintenance
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts			0
PSO
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	91	120	59
PSO | Regulatory Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	(25)	26	(30)
PSO | Regulatory Liabilities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	116	94	89
PSO | Revenues | Vertically Integrated Utilities Revenues
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
PSO | Revenues | Generation & Marketing
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
PSO | Revenues | Electric Generation, Transmission and Distribution Revenues
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
PSO | Purchased Electricity, Fuel and Other Consumables Used for Electric Generation
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
PSO | Other Operation
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts			0
PSO | Maintenance
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts			0
SWEPCo
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	94	109	55
SWEPCo | Regulatory Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	(6)	14	(16)
SWEPCo | Regulatory Liabilities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	100	95	71
SWEPCo | Revenues | Vertically Integrated Utilities Revenues
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
SWEPCo | Revenues | Generation & Marketing
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
SWEPCo | Revenues | Electric Generation, Transmission and Distribution Revenues
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	0	0	0
SWEPCo | Purchased Electricity, Fuel and Other Consumables Used for Electric Generation
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts	$ 0	$ 0	0
SWEPCo | Other Operation
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts			0
SWEPCo | Maintenance
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total Gain (Loss) on Risk Management Contracts			$ 0