Consolidated Statements Of Income And Earnings Reinvested In The Business (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
INCOME
Operating Revenues	$ 629,939	$ 717,261	$ 1,155,301	$ 1,376,119
Operating Expenses:
Purchased Gas	105,940	243,839	162,491	415,035
Property, Franchise and Other Taxes	23,019	25,367	45,434	51,572
Depreciation, Depletion and Amortization	118,935	100,964	234,725	197,564
Total Operating Expenses	379,316	495,884	697,566	900,371
Operating Income	250,623	221,377	457,735	475,748
Other Income (Expense):
Other Income (Deductions)	6,070	2,884	9,801	9,203
Interest Expense on Long-Term Debt	(28,453)	(27,583)	(56,915)	(57,188)
Other Interest Expense	(6,636)	(5,861)	(12,910)	(9,704)
Income Before Income Taxes	221,604	190,817	397,711	418,059
Income Tax Expense	55,332	49,937	98,419	107,489
Net Income Available for Common Stock	166,272	140,880	299,292	310,570
EARNINGS REINVESTED IN THE BUSINESS
Balance at Beginning of Period	1,973,279	1,713,176	1,885,856	1,587,085
Beginning Retained Earnings Unappropriated And Current Period Net Income	2,139,551	1,854,056	2,185,148	1,897,655
Dividends on Common Stock	(45,563)	(43,602)	(91,160)	(87,201)
Balance at March 31	$ 2,090,172	$ 1,810,454	$ 2,090,172	$ 1,810,454
Basic:
Net Income Available for Common Stock (in dollars per share)	$ 1.81	$ 1.53	$ 3.25	$ 3.39
Diluted:
Net Income Available for Common Stock (in dollars per share)	$ 1.80	$ 1.53	$ 3.24	$ 3.37
Weighted Average Common Shares Outstanding:
Used in Basic Calculation (shares)	92,114,415	91,794,765	92,011,772	91,686,110
Used in Diluted Calculation (shares)	92,512,447	92,256,348	92,478,604	92,264,717
Dividends Per Common Share:
Dividends Declared (in dollars per share)	$ 0.495	$ 0.475	$ 0.990	$ 0.950
Earnings Reinvested in The Business [Member]
Other Income (Expense):
Net Income Available for Common Stock	$ 166,272	$ 140,880	$ 299,292	$ 310,570
EARNINGS REINVESTED IN THE BUSINESS
Share Repurchases	(3,816)	0	(3,816)	0
Dividends on Common Stock	(45,563)	(43,602)	(91,160)	(87,201)
Utility
INCOME
Operating Revenues	290,198	406,758	492,119	718,376
Operating Expenses:
Operation and Maintenance	59,288	56,453	112,993	106,805
Exploration and Production and Other Revenues
INCOME
Operating Revenues	264,614	244,552	518,633	521,525
Operating Expenses:
Operation and Maintenance	32,794	31,782	67,620	58,655
Pipeline and Storage and Gathering Revenues
INCOME
Operating Revenues	75,127	65,951	144,549	136,218
Operating Expenses:
Operation and Maintenance	$ 39,340	$ 37,479	$ 74,303	$ 70,740