DERIVATIVES (Volumes of Outstanding Derivative Contracts) (Details)	Jun. 30, 2022 MWh MMBTU	Dec. 31, 2021 MWh MMBTU
Forwards, Futures and Swaps | Natural Gas (MMBtus)
Derivative [Line Items]
Contract Volume	226,068,548	173,361,635
Forwards, Futures and Swaps | Electricity (Megawatt-hours)
Derivative [Line Items]
Contract Volume | MWh	11,270,318	10,283,639
Options | Natural Gas (MMBtus)
Derivative [Line Items]
Contract Volume	27,055,000	14,420,000
Options | Electricity (Megawatt-hours)
Derivative [Line Items]
Contract Volume	502,000	288,000
Congestion revenue rights | Electricity (Megawatt-hours)
Derivative [Line Items]
Contract Volume | MWh	221,557,712	239,857,610