COMMITMENTS AND CONTINGENT LIABILITIES - SCHEDULE OF FUTURE COMMITTED EXPENSES (Details) $ in Thousands	6 Months Ended
Mar. 31, 2025 USD ($)
Long-term Purchase Commitment [Line Items]
Current charges recoverable through BGSS	$ 129,400
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2025	219,081
2026	365,957
2027	237,670
2028	179,085
2029	149,113
Thereafter	1,011,007
ES
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2025	57,193
2026	96,250
2027	40,414
2028	26,607
2029	14,112
Thereafter	52,346
ES \| Natural gas purchases
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2025	21,687
2026	40,749
2027	2,876
2028	0
2029	0
Thereafter	0
ES \| Storage demand fees
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2025	8,047
2026	13,755
2027	7,887
2028	5,114
2029	3,107
Thereafter	4,660
ES \| Pipeline demand fees
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2025	27,459
2026	41,746
2027	29,651
2028	21,493
2029	11,005
Thereafter	47,686
Annual pipeline obligation to be paid over 10 year period	4,000
NJNG
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2025	161,888
2026	269,707
2027	197,256
2028	152,478
2029	135,001
Thereafter	958,661
NJNG \| Natural gas purchases
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2025	32,479
2026	1,954
2027	0
2028	0
2029	0
Thereafter	0
NJNG \| Storage demand fees
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2025	21,477
2026	43,331
2027	35,489
2028	16,282
2029	5,979
Thereafter	2,456
NJNG \| Pipeline demand fees
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2025	107,932
2026	224,422
2027	161,767
2028	136,196
2029	129,022
Thereafter	$ 956,205
Minimum \| ES
Long-term Purchase Commitment [Line Items]
Storage and pipeline capacity, contract term	1 year
Maximum \| ES
Long-term Purchase Commitment [Line Items]
Storage and pipeline capacity, contract term	10 years

Current Charges Recoverable Through Basic Gas Supply Service as shown for the reporting period

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Purchase Obligation, To Be Paid, After Year Four

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Recorded Unconditional Purchase Obligation, To Be Paid Annual By Counterparty Over 10 Year Period

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Storage and Pipeline Capacity, Term of Contract

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Amount of purchase arrangement to be paid in fourth fiscal year following current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of purchase arrangement to be paid in second fiscal year following current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of purchase arrangement to be paid in third fiscal year following current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of recorded unconditional purchase obligation to be paid in remainder of current fiscal year.

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