Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
OPERATING ACTIVITIES
Net Loss Available for Common Stock	$ (328,510)	$ (191,724)
Adjustments to Reconcile Net Income (Loss) to Net Cash Provided by Operating Activities:
Impairment of Oil and Gas Producing Properties	915,552	709,060
Depreciation, Depletion and Amortization	193,300	265,298
Deferred Income Taxes	(269,248)	(198,116)
Excess Tax Benefits Associated with Stock-Based Compensation Awards	(1,786)	(9,064)
Stock-Based Compensation	3,138	8,383
Other	9,685	7,329
Change in:
Hedging Collateral Deposits	8,116	(8,367)
Receivables and Unbilled Revenue	(7,756)	22,175
Gas Stored Underground and Materials and Supplies	15,683	20,259
Unrecovered Purchased Gas Costs	(933)	0
Other Current Assets	15,334	14,367
Accounts Payable	(53,687)	11,153
Amounts Payable to Customers	(21,337)	11,097
Customer Advances	(16,198)	(18,961)
Customer Security Deposits	(396)	2,568
Other Accruals and Current Liabilities	3,375	13,794
Other Assets	3,775	1,124
Other Liabilities	(8,152)	52,261
Net Cash Provided by Operating Activities	459,955	712,636
INVESTING ACTIVITIES
Capital Expenditures	(481,781)	(718,965)
Net Proceeds from Sale of Oil and Gas Producing Properties	115,235	0
Other	(11,163)	(1,065)
Net Cash Used in Investing Activities	(377,709)	(720,030)
Financing Activities
Changes in Notes Payable to Banks and Commercial Paper	0	(85,600)
Excess Tax Benefits Associated with Stock-Based Compensation Awards	1,786	9,064
Net Proceeds from Issuance of Long-Term Debt	0	445,662
Dividends Paid on Common Stock	(100,419)	(97,330)
Net Proceeds from Issuance of Common Stock	8,358	8,743
Net Cash (Used in) Provided by Financing Activities	(90,275)	280,539
Net Increase (Decrease) in Cash and Temporary Cash Investments	(8,029)	273,145
Cash and Temporary Cash Investments at October 1	113,596	36,886
Cash and Temporary Cash Investments at June 30	105,567	310,031
Supplemental Disclosure of Cash Flow Information, Non-Cash Investing Activities:
Non-Cash Capital Expenditures	44,380	122,587
Receivable from Sale of Oil and Gas Producing Properties	$ 22,081	$ 0