SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, DEMAND FEES (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Demand fees	$ 215.1	$ 216.5	$ 211.2
NJRES [Member]
Demand fees	123.0	129.8	112.3
NJNG [Member]
Demand fees	$ 92.1	$ 86.7	$ 98.9
Minimum [Member]
Storage and pipeline capacity, contract term	1 year
Maximum [Member]
Storage and pipeline capacity, contract term	5 years