Significant Accounting Matters (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Amounts Attributable to AEP Common Shareholders
Earnings Attributable to Common Shareholders		$ 796,000	$ 748,600	$ 1,949,200	$ 1,764,600
Total Basic Earnings Per Share Attributable to AEP Common Shareholders		$ 1.59	$ 1.51	$ 3.90	$ 3.56
Weighted Average Dilutive Effect of:
Total Diluted Earnings Per Share Attributable to AEP Common Shareholders		$ 1.58	$ 1.50	$ 3.89	$ 3.55
Organization and Summary of Significant Accounting Policies (Textuals)
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount				377,000	0
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents		$ 1,372,700		$ 1,372,700		$ 392,700
Restricted Cash		54,000		54,000		45,600
Total Cash, Cash Equivalents and Restricted Cash		1,426,700	$ 463,800	1,426,700	$ 463,800	438,300	$ 432,600
Proceeds from Issuance of Debt	[1]			5,115,800
Securities Received as Collateral		309,700		309,700		3,400
Obligation to Return Securities Received as Collateral		$ 38,300		$ 38,300		6,800
Weighted Average Number of Diluted AEP Common Shares Outstanding		502,606,836	497,458,523	500,600,237	496,916,187
Weighted Average Number of Basic AEP Common Shares Outstanding		501,233,680	496,177,968	499,418,278	495,479,190
AEP Texas Inc. [Member]
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents		$ 100		$ 100		100
Restricted Cash		43,900		43,900		28,700
Total Cash, Cash Equivalents and Restricted Cash		44,000	$ 44,900	44,000	$ 44,900	28,800	157,800
AEP Transmission Co [Member]
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents		0	0	0	0	0	0
Appalachian Power Co [Member]
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents		5,000		5,000		5,800
Restricted Cash		10,100		10,100		16,900
Total Cash, Cash Equivalents and Restricted Cash		15,100	13,200	15,100	13,200	22,700	26,800
Securities Received as Collateral		600		600		400
Obligation to Return Securities Received as Collateral		10,700		10,700		0
Indiana Michigan Power Co [Member]
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents		3,200	2,800	3,200	2,800	3,300	2,000
Securities Received as Collateral		300		300		1,700
Obligation to Return Securities Received as Collateral		17,400		17,400		0
Ohio Power Co [Member]
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents		6,800		6,800		7,400
Total Cash, Cash Equivalents and Restricted Cash		6,800	6,600	6,800	6,600	7,400	3,700
Public Service Co Of Oklahoma [Member]
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents		3,600	3,000	3,600	3,000	2,600	1,500
Southwestern Electric Power Co [Member]
Amounts Attributable to AEP Common Shareholders
Earnings Attributable to Common Shareholders		108,900	87,900	208,100	161,800
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents		$ 45,000	$ 25,600	$ 45,000	$ 25,600	$ 13,200	$ 1,600
Restricted Stock Units and Performance Share Units [Member]
Weighted Average Dilutive Effect of:
Weighted Average Dilutive Effect of Shares		1,400,000	1,300,000	1,200,000	1,400,000
Dilutive Securities, Effect on Basic Earnings Per Share		$ (0.01)	$ (0.01)	$ (0.01)	$ (0.01)

[1] Amounts indicated on the statements of cash flows are net of issuance costs and premium or discount and will not tie to the issuance amounts.