Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Operating Activities
Net Income Available for Common Stock	$ 82,252	$ 67,944
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Depreciation, Depletion and Amortization	93,114	72,331
Deferred Income Taxes	30,093	41,000
Excess Tax Benefits Associated with Stock-Based Compensation Awards	(3,149)	0
Stock-Based Compensation	2,960	3,302
Other	(2,095)	4,621
Change in:
Hedging Collateral Deposits	1,094	364
Receivables and Unbilled Revenue	(92,261)	(55,261)
Gas Stored Underground and Materials and Supplies	17,977	3,941
Unrecovered Purchased Gas Costs	3,407	0
Other Current Assets	12,764	7,013
Accounts Payable	39,382	6,163
Amounts Payable to Customers	(3,944)	(4,686)
Customer Advances	(3,281)	(1,987)
Customer Security Deposits	(493)	984
Other Accruals and Current Liabilities	12,347	(5,667)
Other Assets	(6,268)	(597)
Other Liabilities	(7,205)	6,495
Net Cash Provided by Operating Activities	176,694	145,960
Investing Activities
Capital Expenditures	(194,920)	(162,981)
Other	3,615	(3,533)
Net Cash Used in Investing Activities	(191,305)	(166,514)
Financing Activities
Changes in Notes Payable to Banks and Commercial Paper	0	67,000
Excess Tax Benefits Associated with Stock-Based Compensation Awards	3,149	0
Dividends Paid on Common Stock	(31,373)	(60,879)
Net Proceeds from Issuance of Common Stock	1,857	956
Net Cash Provided by (Used in) Financing Activities	(26,367)	7,077
Net Decrease in Cash and Temporary Cash Investments	(40,978)	(13,477)
Cash and Temporary Cash Investments at October 1	64,858	74,494
Cash and Temporary Cash Investments at December 31	23,880	61,017
Supplemental Disclosure of Cash Flow Information, Non-Cash Investing Activities:
Non-Cash Capital Expenditures	$ 52,738	$ 86,144