SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF PARENT COMPANY - AEPTCO PARENT - CONDENSED BALANCE SHEETS (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Accounts Receivable:
General	$ 60	$ 64
Total Accounts Receivable	2,867	2,632
TOTAL CURRENT ASSETS	6,052	5,789
OTHER NONCURRENT ASSETS
TOTAL OTHER NONCURRENT ASSETS	16,034	14,873
TOTAL ASSETS	114,460	103,078
Accounts Payable:
Accounts Payable	3,429	2,638
Long-term Debt Due Within One Year – Nonaffiliated	3,194	3,335
Accrued Interest	544	453
Other Current Liabilities	1,898	1,490
TOTAL CURRENT LIABILITIES	13,314	13,009
NONCURRENT LIABILITIES
Long-term Debt – Nonaffiliated	44,128	39,308
TOTAL NONCURRENT LIABILITIES	68,890	63,045
TOTAL LIABILITIES	82,204	76,054
MEMBER’S EQUITY
Retained Earnings	15,441	13,869
TOTAL LIABILITIES AND EQUITY	114,460	103,078
Parent Company
CURRENT ASSETS
Advances to Affiliates	1,879	1,945
Accounts Receivable:
Total Accounts Receivable	23	33
TOTAL CURRENT ASSETS	2,080	2,173
OTHER NONCURRENT ASSETS
Notes Receivable - Affiliated	1,105	105
Investments in Unconsolidated Subsidiaries	39,550	35,306
TOTAL OTHER NONCURRENT ASSETS	40,900	35,595
TOTAL ASSETS	42,981	37,770
Accounts Payable:
Long-term Debt Due Within One Year – Nonaffiliated	50	1,282
Accrued Interest	129	104
Other Current Liabilities	47	98
TOTAL CURRENT LIABILITIES	1,724	3,616
NONCURRENT LIABILITIES
Long-term Debt – Nonaffiliated	10,050	7,124
TOTAL NONCURRENT LIABILITIES	10,081	7,172
TOTAL LIABILITIES	11,805	10,788
MEMBER’S EQUITY
Retained Earnings	15,441	13,869
TOTAL LIABILITIES AND EQUITY	42,981	37,770
Parent Company | Affiliated Entity
Accounts Receivable:
Affiliated Companies	23	33
Accounts Payable:
Accounts Payable	5	2
AEP TRANSMISSION COMPANY, LLC
Accounts Receivable:
General	0	1
Affiliated Companies	153	134
Total Accounts Receivable	247	194
TOTAL CURRENT ASSETS	322	236
OTHER NONCURRENT ASSETS
TOTAL OTHER NONCURRENT ASSETS	474	318
TOTAL ASSETS	17,999	16,370
Accounts Payable:
Long-term Debt Due Within One Year – Nonaffiliated	425	90
Accrued Interest	46	45
Other Current Liabilities	41	45
TOTAL CURRENT LIABILITIES	1,947	1,409
NONCURRENT LIABILITIES
Long-term Debt – Nonaffiliated	6,174	5,678
TOTAL NONCURRENT LIABILITIES	8,409	8,010
TOTAL LIABILITIES	10,356	9,419
MEMBER’S EQUITY
Paid-in Capital	4,962	3,101
Retained Earnings	1,651	3,850
TOTAL MEMBER’S EQUITY	6,613	6,951
TOTAL LIABILITIES AND EQUITY	17,999	16,370
AEP TRANSMISSION COMPANY, LLC | Affiliated Entity
Accounts Payable:
Accounts Payable	164	117
AEP TRANSMISSION COMPANY, LLC | Parent Company
CURRENT ASSETS
Advances to Affiliates	70	20
Accounts Receivable:
General	32	0
Affiliated Companies	65	62
Total Accounts Receivable	97	62
Notes Receivable - Affiliated	425	90
TOTAL CURRENT ASSETS	592	172
OTHER NONCURRENT ASSETS
Notes Receivable - Affiliated	6,174	8,498
Investments in Unconsolidated Subsidiaries	6,690	4,273
TOTAL OTHER NONCURRENT ASSETS	12,864	12,771
TOTAL ASSETS	13,456	12,943
Accounts Payable:
Accounts Payable	81	69
Long-term Debt Due Within One Year – Nonaffiliated	425	90
Accrued Interest	46	45
Other Current Liabilities	5	15
TOTAL CURRENT LIABILITIES	669	314
NONCURRENT LIABILITIES
Long-term Debt – Nonaffiliated	6,174	5,678
TOTAL NONCURRENT LIABILITIES	6,174	5,678
TOTAL LIABILITIES	6,843	5,992
MEMBER’S EQUITY
Paid-in Capital	4,962	3,101
Retained Earnings	1,651	3,850
TOTAL MEMBER’S EQUITY	6,613	6,951
TOTAL LIABILITIES AND EQUITY	13,456	12,943
AEP TRANSMISSION COMPANY, LLC | Parent Company | Affiliated Entity
Accounts Payable:
Accounts Payable	$ 112	$ 95