Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands	9 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 106,715	$ 89,379
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	39,243	39,934
Deferred income taxes, net	18,700	49,532
Provision for uncollectible accounts	9,495	13,273
Other, net	8,712	11,330
Net change in:
Accounts receivable and accrued utility revenues	(23,902)	(19,040)
Inventories	60,107	128,987
Deferred fuel and power costs	32,951	(1,002)
Accounts payable	(3,688)	(6,472)
Other current assets	5,340	(9,529)
Other current liabilities	(17,988)	(12,755)
Net cash provided by operating activities	235,685	283,637
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for property, plant and equipment	(59,590)	(44,484)
Net costs of property, plant and equipment disposals	(1,414)	(1,848)
Decrease (increase) in restricted cash	643	(3,639)
Net cash used by investing activities	(60,361)	(49,971)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment of dividends	(54,419)	(55,134)
Decrease in bank loans	(17,000)	(154,000)
Other	691
Net cash used by financing activities	(70,728)	(209,134)
Cash and cash equivalents increase	104,596	24,532
CASH AND CASH EQUIVALENTS:
End of period	108,914	38,055
Beginning of period	4,318	13,523
Increase	$ 104,596	$ 24,532