CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash Flows From Operating Activities
Net income (loss)	$ 177,618	$ 206,206
Adjustments to reconcile net income to net cash provided by operating activities:
Asset impairments	0	19,282
Depreciation and amortization:
Charged to depreciation and amortization	122,532	113,297
Charged to other accounts	203	98
Other
Deferred income taxes	102,052	115,302
Other	9,874	10,255
Net assets / liabilities from risk management activities	15,690	(17,478)
Net change in operating assets and liabilities	(67,246)	(8,491)
Net cash provided (used) by operating activities	360,723	438,471
Cash Flows From Investing Activities
Capital expenditures	(311,123)	(246,663)
Other, net	(3,878)	(1,535)
Net cash used in investing activities	(315,001)	(248,198)
Cash Flows From Financing Activities
Net increase in short-term debt	(48,945)	(128,884)
Unwinding of Treasury lock agreements	0	27,803
Repayment of long-term debt	(2,369)	(10,066)
Cash dividends paid	(62,907)	(62,067)
Repurchase of common stock	(12,535)	0
Repurchase of equity awards	(3,509)	(3,333)
Issuance of common stock	164	7,568
Net cash provided by (used in) financing activities	(130,101)	(168,979)
Net increase (decrease) in cash and cash equivalents	(84,379)	21,294
Cash and cash equivalents at beginning of period	131,419	131,952
Cash and cash equivalents at end of period	$ 47,040	$ 153,246