DERIVATIVE INSTRUMENTS - VOLUME (Details) - Bcf	6 Months Ended	12 Months Ended
	Mar. 31, 2022	Sep. 30, 2021
Natural Gas Distribution | Long | Futures
Derivative [Line Items]
Notional amount	29.6	22.2
Natural Gas Distribution | Long | Physical Commodity
Derivative [Line Items]
Notional amount	12.8	7.6
Energy Services | Long | Physical Commodity
Derivative [Line Items]
Notional amount	7.5	0.6
Energy Services | Short | Futures
Derivative [Line Items]
Notional amount	(0.7)	(13.4)
Energy Services | Short | Swaps
Derivative [Line Items]
Notional amount	(0.2)	(0.3)