CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Cash Flows From Operating Activities
Net income	$ 102,861	$ 97,595
Depreciation and amortization:
Charged to depreciation and amortization	71,239	67,593
Charged to other accounts	326	275
Other
Deferred income taxes	59,299	55,418
Other	4,407	4,889
Net Assets Liabilities From Risk Management Activities	(7,495)	(20,828)
Net change in operating assets and liabilities	(160,144)	(177,527)
Net cash provided by operating activities	70,493	27,415
Cash Flows From Investing Activities
Capital expenditures	(291,674)	(261,313)
Other, net	1,029	(739)
Net cash used in investing activities	(290,645)	(262,052)
Cash Flows From Financing Activities
Net decrease in short-term debt	305,309	350,574
Net proceeds from issuance of long-term debt	0	493,538
Settlement of interest rate agreements	0	13,364
Repayments of long-term debt	0	(500,000)
Cash dividends paid	(43,636)	(39,592)
Repurchase of equity awards	0	(7,985)
Issuance of common stock	8,729	6,312
Net cash provided by financing activities	270,402	316,211
Net increase in cash and cash equivalents	50,250	81,574
Cash and cash equivalents at beginning of period	28,653	42,258
Cash and cash equivalents at end of period	$ 78,903	$ 123,832