COMMITMENTS AND CONTINGENT LIABILITIES - LEGAL PROCEEDINGS (Details) (USD $)	3 Months Ended
	Dec. 31, 2012	Sep. 30, 2012
Site Contingency [Line Items]
Site contingency, recovery from third party of environmental remediation cost	$ 20,000,000
Regulatory assets	457,880,000	441,263,000
Minimum [Member]
Site Contingency [Line Items]
Litigation settlement, gross	159,600,000
Maximum [Member]
Site Contingency [Line Items]
Litigation settlement, gross	266,400,000
Environmental remediation costs expended, net of recoveries [Member]
Site Contingency [Line Items]
Regulatory assets	56,333,000	59,745,000
Environmental remediation costs liability for future expenditures [Member]
Site Contingency [Line Items]
Regulatory assets	$ 182,000,000	$ 182,000,000