ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentrations of Credit Risk and Significant Customers (Details) - Customer Concentration Risk - AEP TEXAS INC.	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Revenue \| NRG Energy and Vistra Corp
Concentration Risk [Line Items]
Percentage of Significant Customers Concentration Risk	38.00%	40.00%	41.00%
Revenue \| AEP Subsidiaries
Concentration Risk [Line Items]
Percentage of Significant Customers Concentration Risk	81.00%	80.00%	79.00%
Accounts Receivable \| NRG Energy and Vistra Corp
Concentration Risk [Line Items]
Percentage of Significant Customers Concentration Risk	33.00%	37.00%	34.00%
Accounts Receivable \| AEP Subsidiaries
Concentration Risk [Line Items]
Percentage of Significant Customers Concentration Risk	62.00%	69.00%	60.00%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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+ Details

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References + Details