Consolidated Statements Of Income And Earnings Reinvested In The Business (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
INCOME
Operating Revenues	$ 428,704	$ 502,624	$ 1,804,824	$ 1,750,900
Operating Expenses:
Purchased Gas	35,425	67,948	450,461	369,168
Property, Franchise and Other Taxes	20,427	25,874	71,999	78,093
Depreciation, Depletion and Amortization	102,410	95,857	299,973	275,681
Total Operating Expenses	274,608	334,663	1,174,980	1,126,915
Gain on Sale of Assets	0	12,736	0	12,736
Operating Income	154,096	180,697	629,844	636,721
Other Income (Expense):
Other Income (Deductions)	3,551	(5,649)	12,754	3,291
Interest Expense on Long-Term Debt	(26,311)	(30,091)	(83,499)	(90,300)
Other Interest Expense	(5,781)	(3,882)	(15,485)	(6,561)
Income Before Income Taxes	125,555	141,075	543,614	543,151
Income Tax Expense	32,935	32,917	140,425	135,272
Net Income Available for Common Stock	92,620	108,158	403,189	407,879
EARNINGS REINVESTED IN THE BUSINESS
Balance at Beginning of Period	1,810,454	1,407,683	1,587,085	1,191,175
Beginning Retained Earnings Unappropriated And Current Period Net Income	1,903,074	1,515,841	1,990,274	1,599,054
Dividends on Common Stock	(45,444)	(43,446)	(132,644)	(126,659)
Balance at June 30	$ 1,857,630	$ 1,472,395	$ 1,857,630	$ 1,472,395
Earnings Per Common Share, Basic:
Net Income Available for Common Stock (in dollars per share)	$ 1.01	$ 1.18	$ 4.40	$ 4.46
Earnings Per Common Share, Diluted:
Net Income Available for Common Stock (in dollars per share)	$ 1.00	$ 1.17	$ 4.37	$ 4.43
Weighted Average Common Shares Outstanding:
Used in Basic Calculation (shares)	91,803,638	91,456,265	91,725,286	91,388,417
Used in Diluted Calculation (shares)	92,294,666	92,168,518	92,268,904	92,083,560
Dividends Per Common Share:
Dividends Declared (in dollars per share)	$ 0.495	$ 0.475	$ 1.445	$ 1.385
Utility [Member]
INCOME
Operating Revenues	$ 144,538	$ 179,888	$ 862,914	$ 785,664
Operating Expenses:
Operation and Maintenance	50,080	46,403	156,885	146,523
Exploration and Production and Other [Member]
INCOME
Operating Revenues	216,581	252,638	738,107	758,594
Operating Expenses:
Operation and Maintenance	27,659	64,593	86,315	160,016
Pipeline and Storage and Gathering [Member]
INCOME
Operating Revenues	67,585	70,098	203,803	206,642
Operating Expenses:
Operation and Maintenance	$ 38,607	$ 33,988	$ 109,347	$ 97,434