SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF PARENT COMPANY - AEPTCO PARENT - CONDENSED BALANCE SHEETS (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounts Receivable:
General	$ 64.1	$ 48.7
Total Accounts Receivable	2,631.9	2,447.4
TOTAL CURRENT ASSETS	5,788.8	6,082.1
OTHER NONCURRENT ASSETS
Deferred Charges and Other Noncurrent Assets	3,873.3	3,625.7
TOTAL OTHER NONCURRENT ASSETS	14,873.6	13,908.5
TOTAL ASSETS	103,078.0	96,684.0
Accounts Payable:
Accounts Payable	2,637.6	2,032.5
Long-term Debt Due Within One Year – Nonaffiliated	3,335.0	2,490.5
Accrued Interest	453.3	410.2
Other Current Liabilities	1,490.9	1,251.1
TOTAL CURRENT LIABILITIES	13,009.3	11,583.6
NONCURRENT LIABILITIES
Long-term Debt – Nonaffiliated	39,307.8	37,652.7
TOTAL NONCURRENT LIABILITIES	63,044.8	59,772.0
TOTAL LIABILITIES	76,054.1	71,355.6
MEMBER’S EQUITY
Retained Earnings	13,869.2	12,800.4
TOTAL LIABILITIES, MEZZANINE EQUITY AND EQUITY	103,078.0	96,684.0
AEP TRANSMISSION COMPANY, LLC
CURRENT ASSETS
Advances to Affiliates	30.4	67.1
Accounts Receivable:
General	1.3	0.0
Total Accounts Receivable	194.3	207.7
TOTAL CURRENT ASSETS	235.8	278.8
OTHER NONCURRENT ASSETS
Deferred Charges and Other Noncurrent Assets	8.7	6.5
TOTAL OTHER NONCURRENT ASSETS	318.0	296.0
TOTAL ASSETS	16,370.3	15,072.5
Accounts Payable:
Accounts Payable	360.5	274.7
Long-term Debt Due Within One Year – Nonaffiliated	90.0	95.0
Accrued Interest	44.9	39.6
Other Current Liabilities	44.5	24.7
TOTAL CURRENT LIABILITIES	1,408.8	1,286.1
NONCURRENT LIABILITIES
Long-term Debt – Nonaffiliated	5,678.1	5,319.4
TOTAL NONCURRENT LIABILITIES	8,010.6	7,453.1
TOTAL LIABILITIES	9,419.4	8,739.2
MEMBER’S EQUITY
Paid-in Capital	3,100.6	3,043.4
Retained Earnings	3,850.3	3,289.9
TOTAL MEMBER’S EQUITY	6,950.9	6,333.3	$ 5,873.0	$ 5,376.1
TOTAL LIABILITIES, MEZZANINE EQUITY AND EQUITY	16,370.3	15,072.5
Affiliated Entity | AEP TRANSMISSION COMPANY, LLC
Accounts Receivable:
Affiliated Companies	134.1	125.5
CURRENT LIABILITIES
Advances from Affiliates	84.7	174.3
Accounts Payable:
Accounts Payable	117.0	107.9
Parent Company
CURRENT ASSETS
Advances to Affiliates	1,944.6	2,004.5
Accounts Receivable:
General	0.0	2.7
Total Accounts Receivable	32.5	50.4
TOTAL CURRENT ASSETS	2,172.8	2,344.6
OTHER NONCURRENT ASSETS
Notes Receivable - Affiliated	105.0	295.0
Investments in Unconsolidated Subsidiaries	35,306.2	33,598.6
Deferred Charges and Other Noncurrent Assets	184.6	137.0
TOTAL OTHER NONCURRENT ASSETS	35,595.8	34,030.6
TOTAL ASSETS	37,770.1	36,376.9
CURRENT LIABILITIES
Advances from Affiliates	506.6	728.3
Accounts Payable:
Long-term Debt Due Within One Year – Nonaffiliated	1,281.5	1,104.0
Other Current Liabilities	202.4	137.7
TOTAL CURRENT LIABILITIES	3,615.7	3,931.3
NONCURRENT LIABILITIES
Long-term Debt – Nonaffiliated	7,124.3	7,086.9
TOTAL NONCURRENT LIABILITIES	7,172.8	7,156.4
TOTAL LIABILITIES	10,788.5	11,087.7
MEMBER’S EQUITY
Retained Earnings	13,869.2	12,800.4
TOTAL LIABILITIES, MEZZANINE EQUITY AND EQUITY	37,770.1	36,376.9
Parent Company | AEP TRANSMISSION COMPANY, LLC
CURRENT ASSETS
Advances to Affiliates	20.4	0.0
Accounts Receivable:
General	0.0	28.1
Affiliated Companies	61.7	44.0
Total Accounts Receivable	61.7	72.1
Notes Receivable - Affiliated	90.0	95.0
TOTAL CURRENT ASSETS	172.1	167.1
OTHER NONCURRENT ASSETS
Notes Receivable - Affiliated	8,498.1	5,319.4
Investments in Unconsolidated Subsidiaries	4,272.8	6,476.2
Deferred Charges and Other Noncurrent Assets	0.3	0.0
TOTAL OTHER NONCURRENT ASSETS	12,771.2	11,795.6
TOTAL ASSETS	12,943.3	11,962.7
CURRENT LIABILITIES
Advances from Affiliates	0.0	42.7
Accounts Payable:
Accounts Payable	69.4	35.4
Long-term Debt Due Within One Year – Nonaffiliated	90.0	95.0
Accrued Interest	45.0	39.6
Other Current Liabilities	14.8	15.8
TOTAL CURRENT LIABILITIES	314.3	310.0
NONCURRENT LIABILITIES
Long-term Debt – Nonaffiliated	5,678.1	5,319.4
TOTAL NONCURRENT LIABILITIES	5,678.1	5,319.4
TOTAL LIABILITIES	5,992.4	5,629.4
MEMBER’S EQUITY
Paid-in Capital	3,100.6	3,043.4
Retained Earnings	3,850.3	3,289.9
TOTAL MEMBER’S EQUITY	6,950.9	6,333.3
TOTAL LIABILITIES, MEZZANINE EQUITY AND EQUITY	12,943.3	11,962.7
Parent Company | Affiliated Entity
Accounts Receivable:
Affiliated Companies	32.5	47.7
Accounts Payable:
Accounts Payable	2.2	12.3
Parent Company | Affiliated Entity | AEP TRANSMISSION COMPANY, LLC
Accounts Payable:
Accounts Payable	$ 95.1	$ 81.5