COMMITMENTS AND CONTINGENT LIABILITIES, LEGAL PROCEEDINGS (Details) (USD $)	3 Months Ended
	Dec. 31, 2011	Sep. 30, 2011
Site Contingency [Line Items]
Site Contingency, Recovery from Third Party of Environmental Remediation Cost	$ 20,000,000
Regulatory assets	423,216,000	434,185,000
Maximum [Member]
Site Contingency [Line Items]
Operating Leases, Future Minimum Payments Due, Current	2,100,000
Litigation Settlement, Gross	278,500,000
Operating Leases, Future Minimum Payments, Due Thereafter	5,700,000
Minimum [Member]
Site Contingency [Line Items]
Litigation Settlement, Gross	161,500,000
Enviromental remediation costs expended, net of recoveries [Member]
Site Contingency [Line Items]
Regulatory assets	70,142,000	75,646,000
Enviromental remediation costs liability for future expenditures [Member]
Site Contingency [Line Items]
Regulatory assets	$ 182,900,000	$ 182,900,000