CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Operating revenues	$ 816,429	$ 605,553	$ 3,479,034	$ 2,839,106
Purchased gas cost	249,159	86,870	1,491,700	948,939
Operation and maintenance expense	182,325	184,470	504,787	479,488
Depreciation and amortization expense	134,231	119,348	395,461	353,269
Taxes, other than income	96,127	81,475	271,506	243,376
Operating income	154,587	133,390	815,580	814,034
Other non-operating income	13,263	5,887	27,178	14,793
Interest charges	26,190	20,962	74,969	69,068
Income before income taxes	141,660	118,315	767,789	759,759
Income tax expense	13,113	15,904	65,034	142,916
Net income	$ 128,547	$ 102,411	$ 702,755	$ 616,843
Basic net income per share (USD per share)	$ 0.92	$ 0.78	$ 5.13	$ 4.77
Diluted net income per share (USD per share)	0.92	0.78	5.12	4.77
Cash dividends per share (USD per share)	$ 0.68	$ 0.625	$ 2.04	$ 1.875
Basic weighted average shares outstanding (in shares)	139,881	131,358	136,799	129,185
Diluted weighted average shares outstanding (in shares)	140,227	131,486	137,055	129,229
Other comprehensive income (loss), net of tax
Net unrealized holding losses on available-for-sale securities	$ (106)	$ (36)	$ (336)	$ (165)
Cash flow hedges:
Amortization and unrealized gain (loss) on interest rate agreements	159,737	(79,196)	235,743	118,993
Total other comprehensive income (loss)	159,631	(79,232)	235,407	118,828
Total comprehensive income	288,178	23,179	938,162	735,671
Distribution segment
Operating revenues	772,497	557,931	3,353,800	2,715,644
Pipeline and storage segment
Operating revenues	43,932	47,622	125,234	123,462
Purchased gas cost
Purchased gas cost	249,159	86,870	1,491,700	948,939
Operating Segments | Distribution segment
Operating revenues	773,311	558,750	3,356,279	2,718,074
Purchased gas cost	390,559	202,050	1,881,212	1,304,269
Operation and maintenance expense	133,654	130,454	378,479	363,246
Depreciation and amortization expense	97,106	86,099	286,515	254,636
Taxes, other than income	85,933	72,024	242,214	214,991
Operating income	66,059	68,123	567,859	580,932
Other non-operating income	6,708	1,060	9,173	1,135
Interest charges	12,341	8,540	36,046	33,269
Income before income taxes	60,426	60,643	540,986	548,798
Income tax expense	3,025	7,354	35,163	109,481
Net income	57,401	53,289	505,823	439,317
Operating Segments | Pipeline and storage segment
Operating revenues	183,412	162,987	510,077	476,868
Purchased gas cost	(1,347)	691	(3,075)	(440)
Operation and maintenance expense	48,912	54,329	127,193	117,188
Depreciation and amortization expense	37,125	33,249	108,946	98,633
Taxes, other than income	10,194	9,451	29,292	28,385
Operating income	88,528	65,267	247,721	233,102
Other non-operating income	6,555	4,827	18,005	13,658
Interest charges	13,849	12,422	38,923	35,799
Income before income taxes	81,234	57,672	226,803	210,961
Income tax expense	10,088	8,550	29,871	33,435
Net income	71,146	49,122	196,932	177,526
Operating Segments | Purchased gas cost | Distribution segment
Purchased gas cost	390,559	202,050	1,881,212	1,304,269
Operating Segments | Purchased gas cost | Pipeline and storage segment
Purchased gas cost	(1,347)	691	(3,075)	(440)
Eliminations
Operating revenues	(140,294)	(116,184)	(387,322)	(355,836)
Purchased gas cost	(140,053)	(115,871)	(386,437)	(354,890)
Operation and maintenance expense	(241)	(313)	(885)	(946)
Depreciation and amortization expense	0	0	0	0
Taxes, other than income	0	0	0	0
Operating income	0	0	0	0
Other non-operating income	0	0	0	0
Interest charges	0	0	0	0
Income before income taxes	0	0	0	0
Income tax expense	0	0	0	0
Net income	0	0	0	0
Eliminations | Distribution segment
Operating revenues	814	819	2,479	2,430
Eliminations | Pipeline and storage segment
Operating revenues	139,480	115,365	384,843	353,406
Eliminations | Purchased gas cost
Purchased gas cost	$ (140,053)	$ (115,871)	$ (386,437)	$ (354,890)