COMMITMENTS AND CONTINGENT LIABILITIES - LEGAL PROCEEDINGS (Details) (USD $)	0 Months Ended			6 Months Ended
	Mar. 20, 2013	Mar. 31, 2013	Sep. 30, 2012	Mar. 31, 2013 Minimum [Member]	Mar. 31, 2013 Maximum [Member]	Mar. 31, 2013 Environmental remediation costs expended, net of recoveries [Member]	Sep. 30, 2012 Environmental remediation costs expended, net of recoveries [Member]	Mar. 31, 2013 Environmental remediation costs liability for future expenditures [Member]	Sep. 30, 2012 Environmental remediation costs liability for future expenditures [Member]
Site Contingency [Line Items]
Site contingency, recovery from third party of environmental remediation cost	$ 20,000,000
Regulatory assets		442,208,000	441,263,000			48,830,000	59,745,000	182,000,000	182,000,000
Litigation settlement, gross				$ 159,600,000	$ 266,400,000