DERIVATIVE INSTRUMENTS - OFFSETTING OF ASSETS AND LIABILITIES (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
ES
Asset Derivatives
Fair Value	$ 26,166	$ 30,683
Amounts Offset	(4,213)	(12,619)
Collateral Received/Pledged	(16,178)	(200)
Net Value	5,775	17,864
Liability Derivatives
Fair Value	23,604	57,747
Amounts Offset	(4,213)	(12,619)
Collateral Received/Pledged	(9,728)	0
Net Value	9,663	45,128
ES \| Physical commodity contracts
Asset Derivatives
Fair Value	7,011	10,233
Amounts Offset	(1,236)	(404)
Collateral Received/Pledged	0	(200)
Net Value	5,775	9,629
Liability Derivatives
Fair Value	20,627	30,612
Amounts Offset	(1,236)	(404)
Collateral Received/Pledged	(9,728)	0
Net Value	9,663	30,208
ES \| Financial commodity contracts
Asset Derivatives
Fair Value	19,155	20,432
Amounts Offset	(2,977)	(12,198)
Collateral Received/Pledged	(16,178)	0
Net Value	0	8,234
Liability Derivatives
Fair Value	2,977	27,118
Amounts Offset	(2,977)	(12,198)
Collateral Received/Pledged	0	0
Net Value	0	14,920
ES \| Foreign currency contracts
Asset Derivatives
Fair Value		18
Amounts Offset		(17)
Collateral Received/Pledged		0
Net Value		1
Liability Derivatives
Fair Value		17
Amounts Offset		(17)
Collateral Received/Pledged		0
Net Value		0
NJNG
Asset Derivatives
Fair Value	6,153	337
Amounts Offset	(23)	(85)
Collateral Received/Pledged	0	0
Net Value	6,130	252
Liability Derivatives
Fair Value	508	6,292
Amounts Offset	(23)	(85)
Collateral Received/Pledged	0	0
Net Value	485	6,207
NJNG \| Physical commodity contracts
Asset Derivatives
Fair Value	43	252
Amounts Offset	(3)	0
Collateral Received/Pledged	0	0
Net Value	40	252
Liability Derivatives
Fair Value	488	11
Amounts Offset	(3)	0
Collateral Received/Pledged	0	0
Net Value	485	11
NJNG \| Financial commodity contracts
Asset Derivatives
Fair Value	6,110	85
Amounts Offset	(20)	(85)
Collateral Received/Pledged	0	0
Net Value	6,090	0
Liability Derivatives
Fair Value	20	6,281
Amounts Offset	(20)	(85)
Collateral Received/Pledged	0	0
Net Value	$ 0	$ 6,196

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Collateral or equivalent pledged or received against derivative liabilities.

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Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

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Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, after effect of master netting arrangement and deduction of obligation to return financial collateral not offset and financial instrument subject to master netting arrangement not offset, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and contract can be net settled by means outside contract or delivery of asset. Includes derivative not subject to master netting arrangement or similar agreement.

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Fair value of asset associated with financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

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