DERIVATIVE INSTRUMENTS - VOLUME (Details) - Bcf	3 Months Ended	12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021
Natural Gas Distribution | Long | Futures
Derivative [Line Items]
Notional amount	24.0	22.2
Natural Gas Distribution | Long | Physical Commodity
Derivative [Line Items]
Notional amount	1.5	7.6
Energy Services | Long | Physical Commodity
Derivative [Line Items]
Notional amount	(4.9)	0.6
Energy Services | Short | Futures
Derivative [Line Items]
Notional amount	(22.0)	(13.4)
Energy Services | Short | Swaps
Derivative [Line Items]
Notional amount	(0.2)	(0.3)