CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash Flows From Operating Activities
Net income	$ 315,864	$ 291,560
Depreciation and amortization:
Charged to depreciation and amortization	216,670	204,059
Charged to other accounts	983	853
Other
Deferred income taxes	171,042	164,627
Other	19,767	18,146
Net Assets Liabilities From Risk Management Activities	(8,357)	(13,136)
Net change in operating assets and liabilities	(91,371)	51,473
Net cash provided by operating activities	624,598	717,582
Cash Flows From Investing Activities
Capital expenditures	(796,008)	(667,483)
Other, net	1,627	(1,119)
Net cash used in investing activities	(794,381)	(668,602)
Cash Flows From Financing Activities
Net increase in short-term debt	212,539	48,830
Net proceeds from equity offering	98,660	0
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	(130,363)	(116,645)
Repurchase of equity awards	0	(7,985)
Issuance of common stock	26,500	20,813
Net cash provided by (used in) financing activities	207,336	(48,085)
Net increase in cash and cash equivalents	37,553	895
Cash and cash equivalents at beginning of period	28,653	42,258
Cash and cash equivalents at end of period	$ 66,206	$ 43,153