CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 207,347	$ 230,854
Adjustments to reconcile net income to cash flows from operating activities
Unrealized (gain) on derivative instruments	(40,169)	(8,235)
Depreciation and amortization	61,828	54,210
Amortization of acquired wholesale energy contracts	1,464	3,401
Allowance for equity used during construction	(6,133)	(10,603)
Allowance for doubtful accounts	1,139	10,607
Non cash lease expense	2,559	1,957
Deferred income taxes	16,912	20,909
Equivalent value of ITCs recognized on equipment financing	(727)	0
Manufactured gas plant remediation costs	(14,677)	(6,284)
Equity in earnings, net of distributions received from equity investees	968	(3,543)
Cost of removal - asset retirement obligations	(565)	(512)
Contributions to postemployment benefit plans	(2,324)	(2,018)
Taxes related to stock-based compensation	(166)	(145)
Changes in:
Components of working capital	74,290	6,846
Other noncurrent assets	4,870	18,854
Other noncurrent liabilities	23,836	39,993
Cash flows from operating activities	330,452	356,291
Expenditures for:
Cost of removal	(17,030)	(23,989)
Distribution from equity investees in excess of equity in earnings	478	871
Investments in equity investees, net of return of capital	4,000
Investments in equity investees, net of return of capital		(482)
Cash flows used in investing activities	(296,832)	(245,498)
CASH FLOWS USED IN FINANCING ACTIVITIES
Proceeds from long-term debt	100,000	0
Payments of long-term debt	(10,032)	(11,001)
Proceeds from term loan	150,000	0
Payments of short-term debt, net	(225,090)	(116,850)
Proceeds from sale leaseback transactions - solar	3,300	12,124
Proceeds from sale leaseback transactions	17,300	0
Payments of common stock dividends	(63,725)	(60,894)
Cash settlement of equity forward agreement	0	(388)
Proceeds from issuance of common stock - DRP	7,521	7,540
Tax withholding payments related to net settled stock compensation	(3,737)	(1,772)
Cash flows used in financing activities	(24,463)	(171,241)
Change in cash, cash equivalents and restricted cash	9,157	(60,448)
Cash, cash equivalents and restricted cash at beginning of period	6,043	119,423
Cash, cash equivalents and restricted cash at end of period	15,200	58,975
CHANGES IN COMPONENTS OF WORKING CAPITAL
Receivables	(107,479)	(136,295)
Inventories	125,012	94,233
Recovery of natural gas costs	8,465	(20,279)
Natural gas purchases payable	(25,964)	33,191
Natural gas purchases payable - related parties	(6)	62
Deferred revenue	52,368	(970)
Accounts payable and other	(88,866)	(18,651)
Prepaid expenses	(5,548)	(8,170)
Prepaid and accrued taxes	75,921	59,614
Restricted broker margin accounts	53,708	7,644
Customers' credit balances and deposits	(12,302)	(5,171)
Other current assets	(1,019)	1,638
Total	74,290	6,846
Cash paid for:
Interest (net of amounts capitalized)	42,754	40,465
Income taxes	1,263	3,733
Accrued capital expenditures	53,245	22,840
Utility plant
Expenditures for:
Payments to acquire PP&E	(108,434)	(152,496)
Solar equipment
Expenditures for:
Payments to acquire PP&E	(66,556)	(40,884)
Storage and Transportation and other
Expenditures for:
Payments to acquire PP&E	$ (109,290)	$ (28,518)