FINANCING ACTIVITIES - Schedule of Long-Term Debt Information (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Debt Instrument [Line Items]
Total Long-term Debt Outstanding	$ 47,322	$ 42,643
AEP Texas
Debt Instrument [Line Items]
Total Long-term Debt Outstanding	7,016	6,442
AEPTCo
Debt Instrument [Line Items]
Total Long-term Debt Outstanding	6,599	5,768
APCo
Debt Instrument [Line Items]
Total Long-term Debt Outstanding	6,259	5,661
I&M
Debt Instrument [Line Items]
Total Long-term Debt Outstanding	3,561	3,494
OPCo
Debt Instrument [Line Items]
Total Long-term Debt Outstanding	3,718	3,716
PSO
Debt Instrument [Line Items]
Total Long-term Debt Outstanding	3,526	2,856
SWEPCo
Debt Instrument [Line Items]
Total Long-term Debt Outstanding	$ 4,974	3,981
Senior Unsecured Notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.45%
Senior Unsecured Notes	$ 37,190	$ 36,411
Senior Unsecured Notes | Minimum
Debt Instrument [Line Items]
Interest Rate	1.63%	1.00%
Senior Unsecured Notes | Maximum
Debt Instrument [Line Items]
Interest Rate	8.13%	8.13%
Senior Unsecured Notes | AEP Texas
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.62%
Senior Unsecured Notes	$ 6,472	$ 5,874
Senior Unsecured Notes | AEP Texas | Minimum
Debt Instrument [Line Items]
Interest Rate	2.10%	2.10%
Senior Unsecured Notes | AEP Texas | Maximum
Debt Instrument [Line Items]
Interest Rate	6.76%	6.76%
Senior Unsecured Notes | AEPTCo
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.21%
Senior Unsecured Notes	$ 6,100	$ 5,768
Senior Unsecured Notes | AEPTCo | Minimum
Debt Instrument [Line Items]
Interest Rate	2.75%	2.75%
Senior Unsecured Notes | AEPTCo | Maximum
Debt Instrument [Line Items]
Interest Rate	5.52%	5.52%
Senior Unsecured Notes | APCo
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.84%
Senior Unsecured Notes	$ 4,688	$ 4,984
Senior Unsecured Notes | APCo | Minimum
Debt Instrument [Line Items]
Interest Rate	2.70%	2.70%
Senior Unsecured Notes | APCo | Maximum
Debt Instrument [Line Items]
Interest Rate	7.00%	7.00%
Senior Unsecured Notes | I&M
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.52%
Senior Unsecured Notes	$ 2,847	$ 2,845
Senior Unsecured Notes | I&M | Minimum
Debt Instrument [Line Items]
Interest Rate	3.25%	3.25%
Senior Unsecured Notes | I&M | Maximum
Debt Instrument [Line Items]
Interest Rate	6.05%	6.05%
Senior Unsecured Notes | OPCo
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.16%
Senior Unsecured Notes	$ 3,718	$ 3,716
Senior Unsecured Notes | OPCo | Minimum
Debt Instrument [Line Items]
Interest Rate	1.63%	1.63%
Senior Unsecured Notes | OPCo | Maximum
Debt Instrument [Line Items]
Interest Rate	6.60%	6.60%
Senior Unsecured Notes | PSO
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.59%
Senior Unsecured Notes	$ 3,525	$ 2,854
Senior Unsecured Notes | PSO | Minimum
Debt Instrument [Line Items]
Interest Rate	2.20%	2.20%
Senior Unsecured Notes | PSO | Maximum
Debt Instrument [Line Items]
Interest Rate	6.63%	6.63%
Senior Unsecured Notes | SWEPCo
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.73%
Senior Unsecured Notes	$ 3,653	$ 3,650
Senior Unsecured Notes | SWEPCo | Minimum
Debt Instrument [Line Items]
Interest Rate	1.65%	1.65%
Senior Unsecured Notes | SWEPCo | Maximum
Debt Instrument [Line Items]
Interest Rate	6.20%	6.20%
Pollution Control Bonds
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.62%
Pollution Control Bonds	$ 1,637	$ 1,771
Pollution Control Bonds | Minimum
Debt Instrument [Line Items]
Interest Rate	2.40%	0.63%
Pollution Control Bonds | Maximum
Debt Instrument [Line Items]
Interest Rate	4.70%	4.70%
Pollution Control Bonds | AEP Texas
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.88%
Pollution Control Bonds	$ 441	$ 440
Pollution Control Bonds | AEP Texas | Minimum
Debt Instrument [Line Items]
Interest Rate	2.60%	2.60%
Pollution Control Bonds | AEP Texas | Maximum
Debt Instrument [Line Items]
Interest Rate	4.55%	4.55%
Pollution Control Bonds | APCo
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.92%
Pollution Control Bonds	$ 379	$ 430
Pollution Control Bonds | APCo | Minimum
Debt Instrument [Line Items]
Interest Rate	3.30%	0.63%
Pollution Control Bonds | APCo | Maximum
Debt Instrument [Line Items]
Interest Rate	3.70%	4.22%
Pollution Control Bonds | I&M
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.70%
Interest Rate	3.70%
Pollution Control Bonds	$ 149	$ 190
Pollution Control Bonds | I&M | Minimum
Debt Instrument [Line Items]
Interest Rate		0.75%
Pollution Control Bonds | I&M | Maximum
Debt Instrument [Line Items]
Interest Rate		3.05%
Notes Payable
Debt Instrument [Line Items]
Weighted Average Interest Rate	5.97%
Notes Payable - Nonaffiliated	$ 683	$ 610
Notes Payable | Minimum
Debt Instrument [Line Items]
Interest Rate	2.43%	0.93%
Notes Payable | Maximum
Debt Instrument [Line Items]
Interest Rate	6.89%	6.89%
Notes Payable | I&M
Debt Instrument [Line Items]
Weighted Average Interest Rate	5.24%
Notes Payable - Nonaffiliated	$ 235	$ 143
Notes Payable | I&M | Minimum
Debt Instrument [Line Items]
Interest Rate	3.44%	0.93%
Notes Payable | I&M | Maximum
Debt Instrument [Line Items]
Interest Rate	6.41%	6.41%
Notes Payable | SWEPCo | Related Party
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.24%
Interest Rate	4.24%	0.00%
Notes Payable - Nonaffiliated	$ 1,000	$ 0
Securitization Bonds
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.71%
Securitization Bonds	$ 984	$ 578
Securitization Bonds | Minimum
Debt Instrument [Line Items]
Interest Rate	2.29%	2.06%
Securitization Bonds | Maximum
Debt Instrument [Line Items]
Interest Rate	5.30%	4.88%
Securitization Bonds | AEP Texas
Debt Instrument [Line Items]
Weighted Average Interest Rate	2.29%
Interest Rate		2.29%
Securitization Bonds	$ 102	$ 127
Securitization Bonds | AEP Texas | Minimum
Debt Instrument [Line Items]
Interest Rate		2.06%
Securitization Bonds | APCo
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.77%
Interest Rate	3.77%	3.77%
Securitization Bonds	$ 92	$ 120
Securitization Bonds | SWEPCo
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.88%
Interest Rate	4.88%	4.88%
Securitization Bonds	$ 321	$ 331
Junior Subordinated Notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	5.83%
Junior Subordinated Notes	$ 4,681	$ 2,579
Junior Subordinated Notes | Minimum
Debt Instrument [Line Items]
Interest Rate	3.88%	3.88%
Junior Subordinated Notes | Maximum
Debt Instrument [Line Items]
Interest Rate	7.05%	7.05%
Spent Nuclear Fuel Obligation
Debt Instrument [Line Items]
Spent Nuclear Fuel Obligation	$ 330	$ 316
Spent Nuclear Fuel Obligation | I&M
Debt Instrument [Line Items]
Spent Nuclear Fuel Obligation	$ 330	316
Other Long-term Debt
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.88%
Other Long-term Debt	$ 1,817	$ 378
Other Long-term Debt | Minimum
Debt Instrument [Line Items]
Interest Rate	3.00%	3.00%
Other Long-term Debt | Maximum
Debt Instrument [Line Items]
Interest Rate	13.72%	13.72%
Other Long-term Debt | AEP Texas
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.50%
Interest Rate	4.50%	4.50%
Other Long-term Debt	$ 1	$ 1
Other Long-term Debt | AEPTCo
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.83%
Interest Rate	4.83%	0.00%
Other Long-term Debt	$ 499	$ 0
Other Long-term Debt | APCo
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.89%
Other Long-term Debt	$ 1,100	$ 127
Other Long-term Debt | APCo | Minimum
Debt Instrument [Line Items]
Interest Rate	4.83%	5.75%
Other Long-term Debt | APCo | Maximum
Debt Instrument [Line Items]
Interest Rate	13.72%	13.72%
Other Long-term Debt | PSO
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.00%
Interest Rate	3.00%	3.00%
Other Long-term Debt	$ 1	$ 2