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NATURE OF THE BUSINESS (Details) |  | 12 Months Ended
--- | --- | ---
Jun. 01, 2018 MW | Sep. 30, 2018 subsidiary customer
Natural Gas Distribution |  |
Investment [Line Items] |  |
Total retail customers (in customers) | customer |  | 538,700
NJR Retail Holdings Corporation |  |
Investment [Line Items] |  |
Number of principal subsidiaries (in subsidiaries) | subsidiary |  | 2
Steckman Ridge |  |
Investment [Line Items] |  |
Ownership interest, percent |  | 50.00%
PennEast |  |
Investment [Line Items] |  |
Ownership interest, percent |  | 20.00%
Clean Energy Ventures |  |
Investment [Line Items] |  |
Wind farm total capacity (in MW) | MW | 9.7 |

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