FAIR VALUE MEASUREMENTS AND DERIVATIVE INSTRUMENTS (Schedule of Derivative Volumes) (Details) GWh in Thousands, BTU in Billions	3 Months Ended	12 Months Ended
Mar. 31, 2026 BTU GWh	Dec. 31, 2025 GWh BTU
Power Contracts GWh
Derivative Volume [Line Items]
Derivative, energy measure \| GWh	5,865	1,430
Gas Contracts BBtu
Derivative Volume [Line Items]
Derivative, energy measure \| BTU	71,477	72,959

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.

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