DERIVATIVES (Volumes of Outstanding Derivative Contracts) (Details)	Sep. 30, 2022 MMBTU MWh	Dec. 31, 2021 MWh MMBTU
Forwards, Futures and Swaps | Natural Gas (MMBtus)
Derivative [Line Items]
Contract Volume	215,106,533	173,361,635
Forwards, Futures and Swaps | Electricity (Megawatt-hours)
Derivative [Line Items]
Contract Volume | MWh	10,323,759	10,283,639
Options | Natural Gas (MMBtus)
Derivative [Line Items]
Contract Volume	56,070,000	14,420,000
Options | Electricity (Megawatt-hours)
Derivative [Line Items]
Contract Volume	215,600	288,000
Congestion revenue rights | Electricity (Megawatt-hours)
Derivative [Line Items]
Contract Volume | MWh	215,759,706	239,857,610