DERIVATIVES (Volumes of Outstanding Derivative Contracts) (Details)	Mar. 31, 2024 MMBTU MWh	Dec. 31, 2023 MMBTU MWh
Forwards, Futures and Swaps | Natural Gas (MMBtus)
Derivative [Line Items]
Contract Volume	210,862,229	196,063,296
Forwards, Futures and Swaps | Electricity (MWh)
Derivative [Line Items]
Contract Volume | MWh	8,392,963	9,169,967
Options | Natural Gas (MMBtus)
Derivative [Line Items]
Contract Volume	31,407,500	30,695,000
Options | Electricity (MWh)
Derivative [Line Items]
Contract Volume	646,800	92,400
Congested Revenue Rights | Electricity (MWh)
Derivative [Line Items]
Contract Volume | MWh	162,810,719	170,465,674