REGULATION - REGULATORY FILINGS (Details) - USD ($) $ in Millions						6 Months Ended
	Mar. 29, 2018	Mar. 28, 2018	Mar. 26, 2018	Mar. 01, 2018	Nov. 01, 2017	Mar. 31, 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
March 2018 Annual Petition BPU Filing
Schedule of Regulatory Filings [Line Items]
Requested rate increase (decrease), amount	$ 6.9
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