CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Cash Flows From Operating Activities
Net income (loss)	$ 235,279	$ 220,383
Depreciation and amortization:
Charged to depreciation and amortization	135,615	121,776
Charged to other accounts	566	441
Other
Deferred income taxes	131,292	119,710
Other	10,332	10,746
Net Assets Liabilities From Risk Management Activities	(29,091)	836
Net change in operating assets and liabilities	56,855	17,089
Net cash provided by operating activities	540,848	490,981
Cash Flows From Investing Activities
Capital expenditures	(441,644)	(359,009)
Other, net	(1,346)	(4,904)
Net cash used in investing activities	(442,990)	(363,913)
Cash Flows From Financing Activities
Net decrease in short-term debt	21,839	(369,012)
Net proceeds from equity offering	0	390,205
Net proceeds from issuance of long-term debt	493,538	0
Settlement of interest rate agreements	13,364	0
Repayments of long-term debt	(500,000)	0
Cash dividends paid	(78,074)	(71,380)
Repurchase of equity awards	(7,985)	(6,317)
Issuance of common stock	12,727	(23)
Net cash provided by (used in) financing activities	(44,591)	(56,527)
Net increase (decrease) in cash and cash equivalents	53,267	70,541
Cash and cash equivalents at beginning of period	42,258	66,199
Cash and cash equivalents at end of period	$ 95,525	$ 136,740