Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
OPERATING ACTIVITIES
Net Income (Loss) Available for Common Stock	$ (189,109)	$ 84,740
Adjustments to Reconcile Net Income (Loss) to Net Cash Provided by Operating Activities:
Impairment of Oil and Gas Producing Properties	435,451	0
Depreciation, Depletion and Amortization	70,551	102,747
Deferred Income Taxes	(140,013)	33,207
Excess Tax Benefits Associated with Stock-Based Compensation Awards	(226)	(7,667)
Stock-Based Compensation	960	3,078
Other	3,418	2,358
Change in:
Hedging Collateral Deposits	1,573	(10,734)
Receivables and Unbilled Revenue	(31,150)	(60,947)
Gas Stored Underground and Materials and Supplies	3,466	9,386
Other Current Assets	(5,254)	(5,635)
Accounts Payable	(20,784)	19,378
Amounts Payable to Customers	(11,702)	2,249
Customer Advances	7,189	1,431
Customer Security Deposits	267	630
Other Accruals and Current Liabilities	(14,353)	(6,416)
Other Assets	885	2,142
Other Liabilities	2,904	19,132
Net Cash Provided by Operating Activities	114,073	189,079
INVESTING ACTIVITIES
Capital Expenditures	(186,437)	(244,927)
Net Proceeds from Sale of Oil and Gas Producing Properties	10,574	0
Other	(15,756)	(1,229)
Net Cash Used in Investing Activities	(191,619)	(246,156)
Financing Activities
Changes in Notes Payable to Banks and Commercial Paper	31,400	87,300
Excess Tax Benefits Associated with Stock-Based Compensation Awards	226	7,667
Dividends Paid on Common Stock	(33,415)	(32,400)
Net Proceeds from Issuance of Common Stock	2,068	1,548
Net Cash Provided by Financing Activities	279	64,115
Net Increase (Decrease) in Cash and Temporary Cash Investments	(77,267)	7,038
Cash and Temporary Cash Investments at October 1	113,596	36,886
Cash and Temporary Cash Investments at December 31	36,329	43,924
Supplemental Disclosure of Cash Flow Information, Non-Cash Investing Activities:
Non-Cash Capital Expenditures	93,983	101,664
Receivable from Sale of Oil and Gas Producing Properties	$ 94,364	$ 0