CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands	12 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Cash Flows From Operating Activities
Net income (loss)	$ 207,601	$ 205,839	$ 190,978
Adjustments to reconcile net income to net cash provided by operating activities:
Asset impairments	30,270	0	5,382
Depreciation and amortization:
Charged to depreciation and amortization	233,155	216,960	217,208
Charged to other accounts	228	173	94
Deferred income taxes	117,353	196,731	129,759
Stock-based compensation	11,586	12,655	14,494
Debt financing costs	9,438	11,908	10,364
Other	(961)	(1,245)	(1,177)
Changes in assets and liabilities:
(Increase) decreased in accounts receivable	(96)	(40,401)	244,713
(Increase) decrease in gas stored underground	27,737	54,014	194,287
(Increase) decrease in other current assets	(38,048)	(18,387)	117,737
(Increase) decrease in deferred charges and other assets	(53,519)	14,886	(106,231)
Increase (decrease) in account payable and accrued liabilities	23,904	58,069	(181,978)
Increase (decrease) in other current liabilities	(57,495)	(48,992)	(717)
Increase in deferred credits and other liabilities	71,691	64,266	84,320
Net cash provided by operating activities	582,844	726,476	919,233
Cash Flows From Investing Activities
Capital expenditures	(622,965)	(542,636)	(509,494)
Other, net	(4,421)	(66)	(7,707)
Net cash used in investing activities	(627,386)	(542,702)	(517,201)
Cash Flows From Financing Activities
Net increase in short-term debt	83,306	54,268	(283,981)
Net proceeds from issuance of long-term debt	394,466	0	445,623
Settlement of Treasury lock agreement	20,079	0	1,938
Unwinding of Treasury lock agreements	27,803	0	0
Repayment of long-term debt	(360,131)	(131)	(407,353)
Cash dividends paid	(124,011)	(124,287)	(121,460)
Repurchase of common stock	0	(100,450)	0
Repurchase of equity awards	(5,299)	(1,191)	0
Issuance of common stock	7,796	8,766	27,687
Net cash provided by (used in) financing activities	44,009	(163,025)	(337,546)
Net increase (decrease) in cash and cash equivalents	(533)	20,749	64,486
Cash and cash equivalents at beginning of period	131,952	111,203	46,717
Cash and cash equivalents at end of period	$ 131,419	$ 131,952	$ 111,203

The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production. Includes depreciation recorded for discontinued operations.

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The net change during the reporting period in other noncurrent operating assets not otherwise defined in the taxonomy.

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Transactions that do not result in cash inflows or outflows in the period in which they occur, but affect net income and thus are removed when calculating net cash flow from operating activities using the indirect cash flow method. This element is used when there is not a more specific and appropriate element.

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The component of interest expense representing the noncash expenses charged against earnings in the period to allocate debt discount and premium, and the costs to issue debt and obtain financing over the related debt instruments.

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Includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Entity may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Compensating balance arrangements that do not legally restrict the withdrawal or usage of cash amounts may be reported as Cash and Cash Equivalents, while legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or company statements of intention with regard to particular deposits should not be reported as cash and cash equivalents.

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The net change between the beginning and ending balance of cash and cash equivalents.

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The component of income tax expense for the period representing the net change in the entity's deferred tax assets and liabilities pertaining to continuing operations.

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The net change during the reporting period in the aggregate amount of obligations and expenses incurred but not paid.

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The net change during the reporting period in amount due within one year (or one business cycle) from customers for the credit sale of goods and services.

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The net change during the reporting period in the aggregate value of all inventory held by the reporting entity, associated with underlying transactions that are classified as operating activities.

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The net change during the reporting period in other operating assets not otherwise defined in the taxonomy.

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The net change during the reporting period in other operating obligations not otherwise defined in the taxonomy.

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The net cash inflow (outflow) from financing activity for the period.

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The net cash inflow (outflow) from investing activity.

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The net cash from (used in) all of the entity's operating activities, including those of discontinued operations, of the reporting entity. Operating activities generally involve producing and delivering goods and providing services. Operating activity cash flows include transactions, adjustments, and changes in value that are not defined as investing or financing activities.

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Cash generated by or used in operating activities of continuing operations; excludes cash flows from discontinued operations.

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The portion of consolidated profit or loss for the period, net of income taxes, which is attributable to the parent. If the entity does not present consolidated financial statements, the amount of profit or loss for the period, net of income taxes.

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The other noncash expense, not otherwise specified in the taxonomy, charged against earnings in the period to allocate the cost of tangible and intangible assets over their remaining economic lives.

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The net cash outflow (inflow) for a financial contract that meets the hedge criteria as either cash flow hedge, fair value hedge or hedge of net investment in foreign operations.

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The net cash outflow (inflow) from other investing activities. This element is used when there is not a more specific and appropriate element in the taxonomy.

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The cash outflow from the distribution of an entity's earnings in the form of dividends to common shareholders.

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The cash outflow for purchases of and capital improvements on property, plant and equipment (capital expenditures), software, and other intangible assets.

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The cash inflow from the additional capital contribution to the entity.

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The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

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The net cash inflow (outflow) from other financing activities. This element is used when there is not a more specific and appropriate element in the taxonomy.

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The net cash inflow (outflow) for borrowing having initial term of repayment within one year or the normal operating cycle, if longer.

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The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

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The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock options, amortization of restricted stock, and adjustment for officers compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

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