Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
OPERATING ACTIVITIES
Net Income Available for Common Stock	$ 353,527	$ 237,906
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Depreciation, Depletion and Amortization	177,802	168,812
Deferred Income Taxes	(43,537)	105,073
Stock-Based Compensation	11,770	8,857
Other	12,311	11,084
Change in:
Hedging Collateral Deposits	(542)	(658)
Receivables and Unbilled Revenue	(35,021)	(15,885)
Gas Stored Underground and Materials and Supplies	18,832	15,699
Unrecovered Purchased Gas Costs	4,623	(1,317)
Other Current Assets	(1,185)	8,502
Accounts Payable	2,327	5,046
Amounts Payable to Customers	16,833	(6,467)
Customer Advances	(15,504)	(14,538)
Customer Security Deposits	(1,904)	1,503
Other Accruals and Current Liabilities	26,538	25,423
Other Assets	(10,770)	(3,548)
Other Liabilities	1,441	5,638
Net Cash Provided by Operating Activities	517,541	551,130
INVESTING ACTIVITIES
Capital Expenditures	(403,994)	(314,774)
Net Proceeds from Sale of Oil and Gas Producing Properties	55,506	26,554
Other	(1,759)	(10,186)
Net Cash Used in Investing Activities	(350,247)	(298,406)
Financing Activities
Reduction of Long-Term Debt	(307,047)	0
Dividends Paid on Common Stock	(106,732)	(103,594)
Net Proceeds from Issuance of Common Stock	4,262	6,223
Net Cash Used in Financing Activities	(409,517)	(97,371)
Net Increase (Decrease) in Cash and Temporary Cash Investments	(242,223)	155,353
Cash and Temporary Cash Investments at October 1	555,530	129,972
Cash and Temporary Cash Investments at June 30	313,307	285,325
Supplemental Disclosure of Cash Flow Information, Non-Cash Investing Activities:
Non-Cash Capital Expenditures	$ 71,410	$ 47,508