DERIVATIVE INSTRUMENTS - VOLUME (Details) - Bcf	6 Months Ended	12 Months Ended
Mar. 31, 2024	Sep. 30, 2023
NJNG \| Long \| Futures
Derivative [Line Items]
Notional amount	23.8	32.1
NJNG \| Long \| Physical Commodity
Derivative [Line Items]
Notional amount	5.0	12.1
ES \| Long \| Physical Commodity
Derivative [Line Items]
Notional amount		0.2
ES \| Short \| Futures
Derivative [Line Items]
Notional amount	(3.8)	(6.9)
ES \| Short \| Physical Commodity
Derivative [Line Items]
Notional amount	(3.2)

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480237/815-40-50-5

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