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REGULATION - REGULATORY FILINGS (Details) $ in Thousands |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1 Months Ended | 2 Months Ended | 12 Months Ended |
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Sep. 28, 2022 USD ($) | Sep. 13, 2022 USD ($) | Sep. 07, 2022 USD ($) | Aug. 17, 2022 USD ($) | Jul. 13, 2022 USD ($) | Jun. 01, 2022 USD ($) | Mar. 23, 2022 USD ($) | Jan. 26, 2022 USD ($) | Nov. 19, 2021 USD ($) | Nov. 17, 2021 USD ($) | Mar. 03, 2021 USD ($) | Sep. 25, 2020 | May 29, 2020 USD ($) | Feb. 28, 2019 USD ($) lease | Nov. 30, 2021 USD ($) | Jun. 30, 2021 USD ($) | Apr. 30, 2021 USD ($) | Mar. 31, 2021 USD ($) | Oct. 31, 2020 USD ($) | Jan. 31, 2021 USD ($) | Sep. 30, 2022 USD ($) filing project | Sep. 30, 2021 USD ($)
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory assets-noncurrent |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 500,666 | $ 522,099
Number of interim filings during each fiscal year | filing |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2 |
Number of days notice for refund |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5 days |
NJNG |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Approved rate increase (decrease), amount |  |  |  |  | $ 28,900 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Environmental Remediation Costs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory assets, amortization period |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 7 years |
Postemployment and Other Benefit Costs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory assets, amortization period |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 7 years |
Deferred Storm Damage Costs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory assets, amortization period |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 7 years |
Other Regulatory Asset Noncurrent, PIM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory assets, amortization period |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 7 years |
Regulatory assets-noncurrent |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 635 |
Base Rate Stipulation |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted average cost of capital |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 6.84% |
Approved return on equity |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 9.60% |
Approved equity capital structure, percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 54.00% |
Public utilities, approved depreciation rate, percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2.78% |
SAVEGREEN |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public utility extension term |  |  |  |  |  |  |  |  |  |  |  | 3 years |  |  |  |  |  |  |  |  |  |
Capital investments approved by the BPU |  |  |  |  |  |  |  |  |  |  | $ 126,100 |  |  |  |  |  |  |  |  |  |  |
Financing options |  |  |  |  |  |  |  |  |  |  | 109,400 |  |  |  |  |  |  |  |  |  |  |
Operations and maintenance expense |  |  |  |  |  |  |  |  |  |  | 23,400 |  |  |  |  |  |  |  |  |  |  |
Annual recovery increase |  |  |  |  |  |  |  | $ 2,200 |  |  | $ 15,600 |  |  |  |  |  |  |  |  |  |  |
SAVEGREEN | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory assets, amortization period |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2 years |
Program recovery term |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3 years |
SAVEGREEN | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory assets, amortization period |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 10 years |
Program recovery term |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 10 years |
BPU | NJNG |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Program recovery term |  |  |  | 3 years |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Approved rate increase (decrease), amount |  |  | $ 3,200 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public utilities, investments |  |  |  | $ 500,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
BPU | NJNG |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested rate increase (decrease), amount |  |  |  |  |  |  |  |  |  | $ 79,000 |  |  |  |  |  |  |  |  |  |  |  |
BGSS | NJNG |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested rate increase (decrease), amount |  |  |  |  |  |  |  |  | $ 24,200 |  |  |  |  |  |  |  |  |  |  |  |  |
Interim rate increase (decrease), amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ (20,600) |  |
Interim rate increase (decrease), amount, net of tax |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ (19,300) |  |
BGSS | NJNG |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested rate increase (decrease), amount |  |  |  |  |  | $ 81,900 |  |  |  | 2,900 |  |  |  |  |  |  |  |  |  |  |  |
BGSS Balancing | NJNG |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested rate increase (decrease), amount |  |  |  |  |  | 9,000 |  |  |  | 13,000 |  |  |  |  |  |  |  |  |  |  |  |
Conservation Incentive Program | NJNG |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested rate increase (decrease), amount |  |  |  |  |  | $ 10,200 |  |  |  | $ (6,300) |  |  |  |  |  |  |  |  |  |  |  |
NJNG EE Recovery Rate | NJNG |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Annual recovery increase | $ (3,500) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Approved rate increase (decrease), amount |  |  |  |  |  |  |  |  |  |  |  |  | $ 11,400 |  |  |  |  |  |  |  |  |
RAC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Approved rate increase (decrease), amount |  | $ 3,800 |  |  |  |  | $ 600 |  |  |  |  |  |  |  |  |  | $ 1,300 |  |  |  |  |
NJCEP |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Approved rate increase (decrease), amount |  | $ 2,200 |  |  |  |  | $ (2,900) |  |  |  |  |  |  |  |  |  | $ 6,000 |  |  |  |  |
USF |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested rate increase (decrease), amount | $ (1,600) |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 4,900 |  |  |  |  |  |
SAFE Program |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capital investments approved by the BPU |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 130,000 |
Capital investments approved by the BPU, period |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 4 years |
Capital investments to be recovered approved by the Board of Public Utilities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 200,000 |
Recovery amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 157,500 |
SAFE II |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capital investments approved by the BPU, period |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5 years |
NJ RISE Program |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Approved return on equity |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 9.75% |
Program recovery term |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5 years |
Number of capital investment projects | project |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 6 |
Originally filed petition for capital investments to Board of Public Utilities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 102,500 |
NJ RISE Program | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Approved equity capital structure, percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 6.74% |
NJ RISE Program | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Approved equity capital structure, percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 6.90% |
NJ RISE And SAFE II Capital Investments | NJNG |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capital investment costs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 3,400 |  |  |  |
SAFE II and NJ RISE |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Approved rate increase (decrease), amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 269 |  |  |  |  |  |  |
Infrastructure Investment Program (IIP) | NJNG |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Regulatory Filings [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Program recovery term |  |  |  |  |  |  |  |  |  |  |  |  |  | 5 years |  |  |  |  | 5 years |  |  |
Number of project components | lease |  |  |  |  |  |  |  |  |  |  |  |  |  | 2 |  |  |  |  |  |  |  |
Public utilities, investments |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 507,000 |  |  |  |  | $ 150,000 |  |  |

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