SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, DEMAND FEES (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Demand fees	$ 211.1	$ 214.0	$ 215.1
NJRES [Member]
Demand fees	130.6	122.0	123.0
NJNG [Member]
Demand fees	$ 80.5	$ 92.0	$ 92.1
Minimum [Member]
Storage and pipeline capacity, contract term	1 year
Maximum [Member]
Storage and pipeline capacity, contract term	10 years