DERIVATIVE INSTRUMENTS - VOLUME (Details) - Bcf	3 Months Ended	12 Months Ended
Dec. 31, 2024	Sep. 30, 2024
NJNG \| Long \| Futures
Derivative [Line Items]
Notional amount	26.6	31.9
NJNG \| Long \| Physical Commodity
Derivative [Line Items]
Notional amount	4.9	10.9
ES \| Short \| Futures
Derivative [Line Items]
Notional amount	(7.7)	(7.7)
ES \| Short \| Physical Commodity
Derivative [Line Items]
Notional amount	(0.3)	2.8

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

Name:	us-gaap_DerivativeLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration