DERIVATIVES (Volumes of Outstanding Derivative Contracts) (Details)	Sep. 30, 2025 MWh MMBTU	Dec. 31, 2024 MMBTU MWh
Natural Gas | Forwards, futures, and swaps
Derivative [Line Items]
Contract Volume	274,903,478	179,257,247
Natural Gas | Options
Derivative [Line Items]
Contract Volume	76,780,000	37,717,500
Electricity (MWh) | Forwards, futures, and swaps
Derivative [Line Items]
Contract Volume | MWh	7,698,933	8,576,078
Electricity (MWh) | Options
Derivative [Line Items]
Contract Volume	1,036,400	1,663,200
Electricity (MWh) | Congestion Revenue Rights
Derivative [Line Items]
Contract Volume | MWh	101,477,325	123,040,895