CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash Flows From Operating Activities
Net income	$ 249,209	$ 217,678
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	127,856	115,285
Deferred income taxes	11,813	64,587
Other	(12,689)	(2,976)
Net assets / liabilities from risk management activities	(8,834)	(816)
Net change in other operating assets and liabilities	(305,531)	(236,689)
Net cash provided by operating activities	61,824	157,069
Cash Flows From Investing Activities
Capital expenditures	(684,180)	(456,809)
Debt and equity securities activities, net	2,374	511
Other, net	2,058	2,706
Net cash used in investing activities	(679,748)	(453,592)
Cash Flows From Financing Activities
Net proceeds from equity offering	261,943	216,002
Issuance of common stock through stock purchase and employee retirement plans	3,918	4,007
Proceeds from issuance of long-term debt	596,142	597,390
Cash dividends paid	(90,411)	(79,023)
Debt issuance costs	(6,386)	(5,062)
Net cash provided by financing activities	765,206	733,314
Net increase in cash and cash equivalents	147,282	436,791
Cash and cash equivalents at beginning of period	116,723	20,808
Cash and cash equivalents at end of period	$ 264,005	$ 457,599