RELATED PARTY TRANSACTIONS - ADDITIONAL INFORMATION (Details) $ in Millions		1 Months Ended		12 Months Ended
	Jan. 03, 2025 dth / d	Mar. 31, 2025 Bcf	Apr. 30, 2020 USD ($) Bcf	Sep. 30, 2025 dth / d numberOfAgreement Bcf
NJNG to ES Affiliate
Related Party Transaction [Line Items]
Asset management agreement, period			5 years
NJNG to Steckman RIdge Affiliate
Related Party Transaction [Line Items]
Asset management agreement, period		2 years
Natural gas sold at cost under asset management agreement (in Bcf) | Bcf		3	3
Approximate annual demand fees under agreement | $			$ 6.5
NJNG to Adelphia Affiliate
Related Party Transaction [Line Items]
Number of Transportation Agreements | numberOfAgreement				2
Transportation capacity under precedent agreement with PennEast (in bcf per day)	10,000
NJNG to Adelphia Affiliate | Transportation Precedent Agreement One
Related Party Transaction [Line Items]
Transportation capacity under precedent agreement with PennEast (in bcf per day)				130,000
Transportation precedent agreement term				5 years
NJNG to Adelphia Affiliate | Transportation Precedent Agreement Two
Related Party Transaction [Line Items]
Transportation capacity under precedent agreement with PennEast (in bcf per day)				130,000
Transportation precedent agreement term				15 years
Leaf River Energy Center LLC
Related Party Transaction [Line Items]
Natural gas sold at cost under asset management agreement (in Bcf) | Bcf				3
Storage capacity agreement term				5 years
NJNG and CEV to PPA | Sublease Agreement One
Related Party Transaction [Line Items]
Sublease agreement term				15 years
NJNG and CEV to PPA | Sublease Agreement Two
Related Party Transaction [Line Items]
Sublease agreement term				20 years
NJNG to NJR Subsidiaries
Related Party Transaction [Line Items]
Term of contract				16 years