Consolidated Statements of Income and Earnings Reinvested in the Business - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
INCOME
Operating Revenues	$ 2,173,771	$ 2,186,046	$ 1,742,659
Operating Expenses:
Purchased Gas	437,595	392,093	171,827
Property, Franchise and Other Taxes	92,700	101,182	94,713
Depreciation, Depletion and Amortization	409,573	369,790	335,303
Impairment of Oil and Gas Producing Properties	0	0	76,152
Total Operating Expenses	1,418,624	1,384,266	1,153,801
Gain on Sale of Assets	0	12,736	51,066
Operating Income	755,147	814,516	639,924
Other Income (Expense):
Other Income (Deductions)	18,138	(1,509)	(15,238)
Interest Expense on Long-Term Debt	(111,948)	(120,507)	(141,457)
Other Interest Expense	(19,938)	(9,850)	(4,900)
Income Before Income Taxes	641,399	682,650	478,329
Income Tax Expense	164,533	116,629	114,682
Net Income Available for Common Stock	476,866	566,021	363,647
EARNINGS REINVESTED IN THE BUSINESS
Balance at Beginning of Year	1,587,085	1,191,175	991,630
Beginning Retained Earnings Unappropriated and Current Period Net Income	2,063,951	1,757,196	1,355,277
Dividends on Common Stock	(178,095)	(170,111)	(164,102)
Balance at End of Year	$ 1,885,856	$ 1,587,085	$ 1,191,175
Basic:
Net Income Available for Common Stock (in dollars per share)	$ 5.20	$ 6.19	$ 3.99
Diluted:
Net Income Available for Common Stock (in dollars per share)	$ 5.17	$ 6.15	$ 3.97
Weighted Average Common Shares Outstanding:
Used in Basic Calculation (in shares)	91,748,890	91,410,625	91,130,941
Used in Diluted Calculation (in shares)	92,285,918	92,107,066	91,684,583
Utility and Energy Marketing
INCOME
Operating Revenues	$ 941,779	$ 897,916	$ 667,549
Operating Expenses:
Operation and Maintenance	205,239	193,058	179,547
Exploration and Production and Other
INCOME
Operating Revenues	958,455	1,010,629	837,597
Operating Expenses:
Operation and Maintenance	124,270	191,572	173,041
Pipeline and Storage and Gathering
INCOME
Operating Revenues	273,537	277,501	237,513
Operating Expenses:
Operation and Maintenance	$ 149,247	$ 136,571	$ 123,218