CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Cash Flows From Operating Activities
Net income	$ 1,023,863	$ 908,879
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	549,069	496,522
Deferred income taxes	214,609	138,658
Other	(49,402)	(39,418)
Net assets / liabilities from risk management activities	(1,966)	2,292
Net change in other operating assets and liabilities	(34,841)	(103,869)
Net cash provided by operating activities	1,701,332	1,403,064
Cash Flows From Investing Activities
Capital expenditures	(2,597,787)	(2,129,137)
Debt and equity securities activities, net	(2,348)	(1,701)
Other, net	6,469	11,744
Net cash used in investing activities	(2,593,666)	(2,119,094)
Cash Flows From Financing Activities
Net decrease in short-term debt	0	(241,933)
Net proceeds from equity issuances	568,603	749,987
Issuance of common stock through stock purchase and employee retirement plans	11,532	11,390
Proceeds from issuance of long-term debt	1,143,447	1,240,204
Repayment of securitized long-term debt by AEK	(4,051)	(5,738)
Cash dividends paid	(412,312)	(366,719)
Debt issuance costs	(10,140)	(11,147)
Net cash provided by financing activities	1,297,079	1,376,044
Net increase in cash and cash equivalents and restricted cash and cash equivalents	404,745	660,014
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	$ 713,601	$ 679,262