CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Cash Flows From Operating Activities
Net income (loss)	$ 80,465	$ 68,507
Depreciation and amortization:
Charged to depreciation and amortization	60,500	60,733
Charged to other accounts	128	78
Other
Deferred income taxes	45,951	40,042
Other	3,242	4,692
Net assets / liabilities from risk management activities	(15,641)	(8,426)
Net change in operating assets and liabilities	(144,787)	(180,917)
Net cash provided (used) by operating activities	29,858	(15,291)
Cash Flows From Investing Activities
Capital expenditures	(190,027)	(154,394)
Other, net	(1,273)	(1,080)
Net cash used in investing activities	(191,300)	(155,474)
Cash Flows From Financing Activities
Net increase in short-term debt	256,933	173,905
Repayment of long-term debt	0	(2,303)
Cash dividends paid	(31,992)	(31,517)
Repurchase of common stock	0	(12,535)
Repurchase of equity awards	(3,124)	(3,120)
Issuance of common stock	(13)	76
Net cash provided by (used in) financing activities	221,804	124,506
Net increase (decrease) in cash and cash equivalents	60,362	(46,259)
Cash and cash equivalents at beginning of period	64,239	131,419
Cash and cash equivalents at end of period	$ 124,601	$ 85,160