CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Cash Flows From Operating Activities
Net income	$ 351,858	$ 311,292
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	180,533	164,608
Deferred income taxes	71,107	44,108
Other	(19,279)	(16,839)
Net assets / liabilities from risk management activities	1,891	5,589
Net change in other operating assets and liabilities	(304,088)	(263,478)
Net cash provided by operating activities	282,022	245,280
Cash Flows From Investing Activities
Capital expenditures	(891,191)	(769,650)
Debt and equity securities activities, net	(490)	(78)
Other, net	2,740	5,353
Net cash used in investing activities	(888,941)	(764,375)
Cash Flows From Financing Activities
Net decrease in short-term debt	0	(241,933)
Net proceeds from equity issuances	379,490	254,022
Issuance of common stock through stock purchase and employee retirement plans	4,047	3,746
Proceeds from issuance of long-term debt	645,372	898,275
Cash dividends paid	(135,453)	(119,898)
Debt issuance costs	(5,987)	(8,920)
Net cash provided by financing activities	887,469	785,292
Net increase in cash and cash equivalents and restricted cash and cash equivalents	280,550	266,197
Cash and cash equivalents and restricted cash and cash equivalents at beginning of period	308,856	19,248
Cash and cash equivalents and restricted cash and cash equivalents at end of period	$ 589,406	$ 285,445