Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended		12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Sep. 30, 2011
Operating Activities
Net Income Available for Common Stock	$ 171,275	$ 221,045
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Gain on Sale of Unconsolidated Subsidiaries	0	(50,879)
Depreciation, Depletion and Amortization	199,925	170,617
Deferred Income Taxes	104,948	140,326
Excess Tax Costs (Benefits) Associated with Stock-Based Compensation Awards	(1,511)	1,224
Other	6,618	7,351
Change in:
Hedging Collateral Deposits	16,309	(26,850)
Receivables and Unbilled Utility Revenue	23,008	(25,919)
Gas Stored Underground and Materials and Supplies	30,853	22,387
Unrecovered Purchased Gas Costs	(2,100)	0
Prepayments and Other Current Assets	18,190	83,541
Accounts Payable	(38,590)	5,506
Amounts Payable to Customers	2,242	(12,448)
Customer Advances	(19,328)	(26,617)
Customer Security Deposits	(474)	(648)
Other Accruals and Current Liabilities	17,083	36,446
Other Assets	(12,796)	8,582
Other Liabilities	25,338	(17,382)
Net Cash Provided by Operating Activities	540,990	536,282
Investing Activities
Capital Expenditures	(776,896)	(583,739)
Net Proceeds from Sale of Unconsolidated Subsidiaries	0	59,365
Net Proceeds from Sale of Oil and Gas Producing Properties	0	69,435	55,400
Other	(1,267)	(2,908)
Net Cash Used in Investing Activities	(778,163)	(457,847)
Financing Activities
Changes in Notes Payable to Banks and Commercial Paper	30,200	0
Excess Tax (Costs) Benefits Associated with Stock-Based Compensation Awards	1,511	(1,224)
Net Proceeds from Issuance of Long-Term Debt	496,085	0
Reduction of Long-Term Debt	(150,000)	(200,000)
Dividends Paid on Common Stock	(88,404)	(85,201)
Net Proceeds from Issuance (Repurchase) of Common Stock	8,168	(4,471)
Net Cash Provided by (Used in) Financing Activities	297,560	(290,896)
Net Increase (Decrease) in Cash and Temporary Cash Investments	60,387	(212,461)
Cash and Temporary Cash Investments at October 1	80,428	397,171	397,171
Cash and Temporary Cash Investments at June 30	$ 140,815	$ 184,710	$ 80,428