ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Accounting Policies [Abstract]
Net Income (Loss) Available to Common Stockholders, Basic	$ 3,580	$ 2,967	$ 2,208
Net Income (Loss) Available to Common Stockholders, Diluted	$ 3,580	$ 2,967	$ 2,208
Weighted-Average Number of Basic AEP Common Shares Outstanding (in shares)	534,535,444	530,092,672	518,903,682
Weighted-Average Number of Basic AEP Common Shares Outstanding (in USD per share)	$ 6.70	$ 5.60	$ 4.26
Weighted-Average Dilutive Effect	3,000,000.0	1,200,000	1,300,000
Weighted-Average Dilutive Effect (in USD per share)	$ (0.04)	$ (0.02)	$ (0.02)
Weighted-Average Number of Diluted AEP Common Shares Outstanding	537,500,000	531,300,000	520,200,000
Weighted-Average Number of Diluted AEP Common Shares Outstanding (in USD per share)	$ 6.66	$ 5.58	$ 4.24