DERIVATIVE INSTRUMENTS - Contracts (Details)	6 Months Ended
Sep. 30, 2022 USD ($) item $ / t $ / MMBTU $ / t $ / MWh
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Natural Gas Unobservable Input Per Mega Watt Hour \| $ / MWh	5
Natural Gas Unobservable Input Per MMBtu \| $ / MMBTU	0.50
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity Curves Extension Term	5 years
Maximum \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Basis Curve Extension Term	15 months
Minimum \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Basis Curve Extension Term	12 months
Natural gas contracts \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of Market Observable Curves \| item	3
Physical forward contracts and options \| Electricity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional units	31,490,189
Contract price \| $ / MWh	50.69
Physical forward contracts and options \| Natural gas contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional units	70,403,970
Contract price \| $ / MMBTU	5.33
Physical forward contracts and options \| RECs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional units	4,450,234
Contract price \| $ / t	11.04
Physical forward contracts and options \| Green Gas Certificates
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional units	140,000
Contract price \| $ / t	1.39
Physical forward contracts and options \| Electricity generation capacity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional units	1,209
Contract price \| $ / t	4,027.58
Physical forward contracts and options \| Ancillary contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional units	874,520
Contract price \| $ / MWh	20.41
Financial swap contracts and options \| Electricity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional units	24,117,816
Contract price \| $ / MWh	59.88
Financial swap contracts and options \| Natural gas contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional units	110,708,400
Contract price \| $ / MMBTU	4.05
Financial swap contracts and options \| Ancillary contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional units	1,806,946
Contract price \| $ / MWh	20.36