REGULATION - REGULATORY FILINGS (Details) - USD ($) $ in Millions								9 Months Ended
	Jul. 24, 2018	Jun. 22, 2018	May 25, 2018	Mar. 28, 2018	Mar. 26, 2018	Mar. 01, 2018	Nov. 01, 2017	Jun. 30, 2018
SAVEGREEN
Schedule of Regulatory Filings [Line Items]
Approved rate increase (decrease), amount							$ (3.9)
Requested capital investments				$ 341.0
RAC
Schedule of Regulatory Filings [Line Items]
Requested rate increase (decrease), amount								$ (2.4)
NJCEP
Schedule of Regulatory Filings [Line Items]
Requested rate increase (decrease), amount								1.8
March 2018 Required BPU Filing
Schedule of Regulatory Filings [Line Items]
Requested rate increase (decrease), amount						$ (19.7)
Requested customer refunds, amount						$ 31.0
May 2018 Annual Petition BPU Filing BGSS Rate
Schedule of Regulatory Filings [Line Items]
Increase (decrease) in annual revenues			$ 10.8
May 2018 Annual Petition BPU Filing CIP Rate
Schedule of Regulatory Filings [Line Items]
Increase (decrease) in annual revenues			(30.9)
May 2018 Annual Petition BPU Filing EE Rate
Schedule of Regulatory Filings [Line Items]
Increase (decrease) in annual revenues			$ (7.0)
June 2018 Annual USF Compliance Filing
Schedule of Regulatory Filings [Line Items]
Increase (decrease) in annual revenues		$ 7.3
Natural Gas Distribution
Schedule of Regulatory Filings [Line Items]
Tax Cuts and Jobs Act of 2017, regulatory liability								228.4
Tax Cuts and Jobs Act of 2017, revaluation of deferred income taxes, provisional liability								164.3
Tax Cuts and Jobs Act of 2017, income tax effects on revaluation, provisional liability								$ 64.1
Conservation Incentive Program | March 2018 BGSS/CIP Filing
Schedule of Regulatory Filings [Line Items]
Approved rate increase (decrease), amount					$ (16.2)
Increase (decrease) in annual revenues					$ 3.7
Subsequent Event | March 2018 Annual Petition BPU Filing
Schedule of Regulatory Filings [Line Items]
Requested rate increase (decrease), amount	$ 6.8