CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash Flows From Operating Activities
Net income (loss)	$ 220,383	$ 196,890
Depreciation and amortization:
Charged to depreciation and amortization	121,776	118,608
Charged to other accounts	441	265
Other
Deferred income taxes	119,710	106,891
Other	10,746	5,519
Net Assets Liabilities From Risk Management Activities	836	(14,709)
Net change in operating assets and liabilities	17,089	(37,123)
Net cash provided by operating activities	490,981	376,341
Cash Flows From Investing Activities
Capital expenditures	(359,009)	(389,117)
Other, net	(4,904)	(3,700)
Net cash used in investing activities	(363,913)	(392,817)
Cash Flows From Financing Activities
Net decrease in short-term debt	(369,012)	(342,141)
Net proceeds from issuance of long-term debt	0	493,793
Settlement of Treasury lock agreements	0	(66,626)
Repayments of Long-term Debt	0	(131)
Cash dividends paid	(71,380)	(64,008)
Repurchase of equity awards	(6,317)	(3,124)
Net proceeds from equity offering	390,205	0
Other	(23)	21
Net cash provided by (used in) financing activities	(56,527)	17,784
Net increase (decrease) in cash and cash equivalents	70,541	1,308
Cash and cash equivalents at beginning of period	66,199	64,239
Cash and cash equivalents at end of period	$ 136,740	$ 65,547