Atmos Energy (ATO) 10-Q 4 May 22 2022 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Mar. 31, 2022	Apr. 29, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2022
Document Transition Report	false
Entity File Number	1-10042
Entity Registrant Name	Atmos Energy Corp
Entity Incorporation, State or Country Code	TX
Entity Tax Identification Number	75-1743247
Entity Address, Address Line One	1800 Three Lincoln Centre
Entity Address, Address Line Two	5430 LBJ Freeway
Entity Address, City or Town	Dallas
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	75240
City Area Code	972
Local Phone Number	934-9227
Title of 12(b) Security	Common stock
Trading Symbol	ATO
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		139,015,012
Entity Central Index Key	0000731802
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
ASSETS
Property, plant and equipment	$ 19,019,069	$ 17,885,098
Less accumulated depreciation and amortization	2,934,096	2,821,128
Net property, plant and equipment	16,084,973	15,063,970
Current assets
Cash and cash equivalents	582,495	116,723
Accounts receivable, net (See Note 5)	565,184	342,967
Gas stored underground	96,295	178,116
Other current assets (See Note 8)	2,285,022	2,200,909
Total current assets	3,528,996	2,838,715
Goodwill	731,257	731,257
Deferred charges and other assets (See Note 8)	925,917	974,720
Total assets	21,271,143	19,608,662
Shareholders’ equity
Common stock, no par value (stated at $0.005 per share); 200,000,000 shares authorized; issued and outstanding: March 31, 2022 — 139,012,029 shares; September 30, 2021 — 132,419,754 shares	695	662
Additional paid-in capital	5,634,020	5,023,751
Accumulated other comprehensive income	145,579	69,803
Retained earnings	3,202,937	2,812,673
Shareholders’ equity	8,983,231	7,906,889
Long-term debt	5,757,595	4,930,205
Total capitalization	14,740,826	12,837,094
Current liabilities
Accounts payable and accrued liabilities	354,003	423,222
Other current liabilities	653,009	686,681
Current maturities of long-term debt	2,201,404	2,400,452
Total current liabilities	3,208,416	3,510,355
Deferred income taxes	1,848,626	1,705,809
Regulatory excess deferred taxes	470,918	549,227
Regulatory cost of removal obligation	476,026	468,688
Deferred credits and other liabilities	526,331	537,489
Total capitalization and liabilities	$ 21,271,143	$ 19,608,662

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2022	Sep. 30, 2021
Statement of Financial Position [Abstract]
Common stock stated value (USD per share)	$ 0.005	$ 0.005
Common stock authorized (in shares)	200,000,000	200,000,000
Common stock issued (in shares)	139,012,029	132,419,754
Common stock outstanding (in shares)	139,012,029	132,419,754

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Operating revenues	$ 1,649,819	$ 1,319,073	$ 2,662,605	$ 2,233,553
Purchased gas cost	871,378	573,809	1,242,541	862,069
Operation and maintenance expense	163,352	156,375	322,462	295,018
Depreciation and amortization expense	133,374	118,636	261,230	233,921
Taxes, other than income	96,583	88,449	175,379	161,901
Operating income	385,132	381,804	660,993	680,644
Other non-operating income	5,213	2,834	13,915	8,906
Interest charges	28,928	26,096	48,779	48,106
Income before income taxes	361,417	358,542	626,129	641,444
Income tax expense	36,418	61,788	51,921	127,012
Net income	$ 324,999	$ 296,754	$ 574,208	$ 514,432
Basic net income per share (USD per share)	$ 2.37	$ 2.30	$ 4.24	$ 4.01
Diluted net income per share (USD per share)	2.37	2.30	4.24	4.01
Cash dividends per share (USD per share)	$ 0.68	$ 0.625	$ 1.36	$ 1.25
Basic weighted average shares outstanding (in shares)	136,834	129,161	135,259	128,098
Diluted weighted average shares outstanding (in shares)	137,250	129,164	135,470	128,100
Other comprehensive income (loss), net of tax
Net unrealized holding losses on available-for-sale securities	$ (161)	$ (66)	$ (230)	$ (129)
Cash flow hedges:
Amortization and unrealized gain on interest rate agreements	121,884	138,005	76,006	198,189
Total other comprehensive income	121,723	137,939	75,776	198,060
Total comprehensive income	446,722	434,693	649,984	712,492
Distribution segment
Operating revenues	1,609,667	1,281,826	2,581,303	2,157,713
Pipeline and storage segment
Operating revenues	40,152	37,247	81,302	75,840
Purchased gas cost
Purchased gas cost	871,378	573,809	1,242,541	862,069
Operating Segments | Distribution segment
Operating revenues	1,610,546	1,282,674	2,582,968	2,159,324
Purchased gas cost	993,854	691,147	1,490,653	1,102,219
Operation and maintenance expense	121,541	123,990	244,825	232,792
Depreciation and amortization expense	96,612	85,667	189,409	168,537
Taxes, other than income	87,236	78,615	156,281	142,967
Operating income	311,303	303,255	501,800	512,809
Other non-operating income	549	(760)	2,465	75
Interest charges	15,157	14,017	23,705	24,729
Income before income taxes	296,695	288,478	480,560	488,155
Income tax expense	27,844	56,142	32,138	102,127
Net income	268,851	232,336	448,422	386,028
Operating Segments | Pipeline and storage segment
Operating revenues	163,747	154,168	326,665	313,881
Purchased gas cost	1,683	113	(1,728)	(1,131)
Operation and maintenance expense	42,126	32,703	78,281	62,859
Depreciation and amortization expense	36,762	32,969	71,821	65,384
Taxes, other than income	9,347	9,834	19,098	18,934
Operating income	73,829	78,549	159,193	167,835
Other non-operating income	4,664	3,594	11,450	8,831
Interest charges	13,771	12,079	25,074	23,377
Income before income taxes	64,722	70,064	145,569	153,289
Income tax expense	8,574	5,646	19,783	24,885
Net income	56,148	64,418	125,786	128,404
Operating Segments | Purchased gas cost | Distribution segment
Purchased gas cost	993,854	691,147	1,490,653	1,102,219
Operating Segments | Purchased gas cost | Pipeline and storage segment
Purchased gas cost	1,683	113	(1,728)	(1,131)
Eliminations
Operating revenues	(124,474)	(117,769)	(247,028)	(239,652)
Purchased gas cost	(124,159)	(117,451)	(246,384)	(239,019)
Operation and maintenance expense	(315)	(318)	(644)	(633)
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	879	848	1,665	1,611
Eliminations | Pipeline and storage segment
Operating revenues	123,595	116,921	245,363	238,041
Eliminations | Purchased gas cost
Purchased gas cost	$ (124,159)	$ (117,451)	$ (246,384)	$ (239,019)

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
Net unrealized holding gains (losses) on available-for-sale securities, tax	$ (47)	$ (19)	$ (67)	$ (37)
Amortization and unrealized gain (loss) on interest rate agreements, tax	$ 35,228	$ 39,887	$ 21,968	$ 57,282

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash Flows From Operating Activities
Net income	$ 574,208	$ 514,432
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization expense	261,230	233,921
Deferred income taxes	40,122	128,725
Other	(12,812)	(938)
Net assets / liabilities from risk management activities	(4,172)	(1,954)
Net change in Winter Storm Uri long-term regulatory asset (See Note 8)	0	(2,093,534)
Net change in other operating assets and liabilities	(218,092)	(182,898)
Net cash provided by (used in) operating activities	640,484	(1,402,246)
Cash Flows From Investing Activities
Capital expenditures	(1,190,029)	(845,728)
Debt and equity securities activities, net	3,758	(5,506)
Other, net	4,302	5,171
Net cash used in investing activities	(1,181,969)	(846,063)
Cash Flows From Financing Activities
Net proceeds from equity issuances	594,320	460,678
Issuance of common stock through stock purchase and employee retirement plans	8,010	8,291
Proceeds from issuance of long-term debt	798,802	2,797,346
Repayment of long-term debt	(200,000)	0
Cash dividends paid	(183,944)	(159,348)
Debt issuance costs	(8,196)	(14,155)
Other	(1,735)	0
Net cash provided by financing activities	1,007,257	3,092,812
Net increase in cash and cash equivalents	465,772	844,503
Cash and cash equivalents at beginning of period	116,723	20,808
Cash and cash equivalents at end of period	$ 582,495	$ 865,311

Nature of Business

Nature of Business	6 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business	Nature of Business Atmos Energy Corporation (“Atmos Energy” or the “Company”) and its subsidiaries are engaged in the regulated natural gas distribution and pipeline and storage businesses. Our distribution business is subject to federal and state regulation and/or regulation by local authorities in each of the states in which our regulated divisions and subsidiaries operate. Our distribution business delivers natural gas through sales and transportation arrangements to over three million residential, commercial, public authority and industrial customers through our six regulated distribution divisions, which at March 31, 2022, covered service areas located in eight states. Our pipeline and storage business, which is also subject to federal and state regulations, includes the transportation of natural gas to our Texas and Louisiana distribution systems and the management of our underground storage facilities used to support our distribution business in various states.

Unaudited Financial Information

Unaudited Financial Information	6 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Unaudited Financial Information	Unaudited Financial Information These consolidated interim-period financial statements have been prepared in accordance with accounting principles generally accepted in the United States on the same basis as those used for the Company’s audited consolidated financial statements included in our Annual Report on Form 10-K for the fiscal year ended September 30, 2021. In the opinion of management, all material adjustments (consisting of normal recurring accruals) necessary for a fair presentation have been made to the unaudited consolidated interim-period financial statements. These consolidated interim-period financial statements are condensed as permitted by the instructions to Form 10-Q and should be read in conjunction with the audited consolidated financial statements of Atmos Energy Corporation included in our Annual Report on Form 10-K for the fiscal year ended September 30, 2021. Because of seasonal and other factors, the results of operations for the six-month period ended March 31, 2022 are not indicative of our results of operations for the full 2022 fiscal year, which ends September 30, 2022. Except as described in Note 6 to the unaudited condensed consolidated financial statements, no events have occurred subsequent to the balance sheet date that would require recognition or disclosure in the unaudited condensed consolidated financial statements. Significant accounting policies Our accounting policies are described in Note 2 to the consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2021. During the second quarter of fiscal 2022, we completed our annual goodwill impairment assessment using a qualitative assessment, as permitted under U.S. GAAP. We test for goodwill at the reporting unit level on an annual basis and between annual tests if an event occurs or circumstances change that would more likely than not reduce the fair value of the reporting unit. Based on the assessment performed, we determined that our goodwill was not impaired. Recently issued accounting pronouncements In November 2021, the Financial Accounting Standards Board (FASB) issued guidance which will require disclosure about government assistance in the notes to the financial statements. The amendment requires annual disclosures about transactions with a government that are accounted for by applying a grant or contribution accounting model by analogy, including information about the nature of the transactions and the related accounting policy used to account for the transactions, the line items on the balance sheet and income statement that are affected by the transactions and the significant terms and conditions of the transactions, including commitments and contingencies. The amendment is effective for us beginning October 1, 2022; however, we elected to adopt this amendment during the first quarter of fiscal 2022 as permitted by the guidance. As the guidance is related only to disclosures in the notes to the financial statements, there will be no impact on our financial position, results of operations or cash flows. In March 2020, the FASB issued optional guidance which will ease the potential burden in accounting for or recognizing the effects of reference rate reform on financial reporting. The amendments provide optional expedients and exceptions for applying U.S. GAAP to contracts, hedging relationships and other transactions affected by the cessation of the London Interbank Offered Rate (LIBOR). The amendments can be elected immediately, as of March 12, 2020, through December 31, 2022. We are currently evaluating if we will apply the optional guidance as we assess the impact of the cessation of LIBOR on our current contracts and hedging relationships and the potential impact on our financial position, results of operations and cash flows. Regulatory assets and liabilities Accounting principles generally accepted in the United States require cost-based, rate-regulated entities that meet certain criteria to reflect the authorized recovery of costs due to regulatory decisions in their financial statements. As a result, certain costs are permitted to be capitalized rather than expensed because they can be recovered through rates. We record certain costs as regulatory assets when future recovery through customer rates is considered probable. Regulatory liabilities are recorded when it is probable that revenues will be reduced for amounts that will be credited to customers through the ratemaking process. Substantially all of our regulatory assets are recorded as a component of other current assets and deferred charges and other assets and our regulatory liabilities are recorded as a component of other current liabilities and deferred credits and other liabilities. Deferred gas costs are recorded either in other current assets or liabilities. Significant regulatory assets and liabilities as of March 31, 2022 and September 30, 2021 included the following: March 31, September 30, (In thousands) Regulatory assets: Pension and postretirement benefit costs $ 37,927 $ 45,922 Infrastructure mechanisms (1) 204,915 222,795 Winter Storm Uri incremental costs (2) 2,106,521 2,100,728 Deferred gas costs 21,366 66,395 Regulatory excess deferred taxes 48,352 45,370 Recoverable loss on reacquired debt 3,521 3,789 Deferred pipeline record collection costs 34,149 32,099 Other 18,794 4,343 $ 2,475,545 $ 2,521,441 Regulatory liabilities: Regulatory excess deferred taxes $ 626,874 $ 705,084 Regulatory cost of removal obligation 552,100 541,511 Deferred gas costs 83,834 52,553 Asset retirement obligation 18,373 18,373 APT annual adjustment mechanism 27,397 31,110 Pension and postretirement benefit costs 53,370 56,201 Other 27,571 19,363 $ 1,389,519 $ 1,424,195 (1) Infrastructure mechanisms in Texas, Louisiana and Tennessee allow for the deferral of all eligible expenses associated with capital expenditures incurred pursuant to these rules, including the recording of interest on deferred expenses until the next rate proceeding (rate case or annual rate filing), at which time investment and costs would be recoverable through base rates. (2) Includes extraordinary gas costs subject to securitization incurred during Winter Storm Uri and permissible carrying costs. See Note 8 to the unaudited condensed consolidated financial statements for further information. This amount is recorded within other current assets and deferred charges and other assets on the condensed consolidated balance sheet as of March 31, 2022.

Segment Information

Segment Information	6 Months Ended
	Mar. 31, 2022
Segment Reporting [Abstract]
Segment Information	Segment Information We manage and review our consolidated operations through the following reportable segments: • The distribution segment is primarily comprised of our regulated natural gas distribution and related sales operations in eight states. • The pipeline and storage segment is comprised primarily of the pipeline and storage operations of our Atmos Pipeline-Texas division and our natural gas transmission operations in Louisiana. The accounting policies of the segments are the same as those described in the summary of significant accounting policies found in our Annual Report on Form 10-K for the fiscal year ended September 30, 2021. Income statements and capital expenditures for the three and six months ended March 31, 2022 and 2021 by segment are presented in the following tables: Three Months Ended March 31, 2022 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 1,609,667 $ 40,152 $ — $ 1,649,819 Intersegment revenues 879 123,595 (124,474) — Total operating revenues 1,610,546 163,747 (124,474) 1,649,819 Purchased gas cost 993,854 1,683 (124,159) 871,378 Operation and maintenance expense 121,541 42,126 (315) 163,352 Depreciation and amortization expense 96,612 36,762 — 133,374 Taxes, other than income 87,236 9,347 — 96,583 Operating income 311,303 73,829 — 385,132 Other non-operating income 549 4,664 — 5,213 Interest charges 15,157 13,771 — 28,928 Income before income taxes 296,695 64,722 — 361,417 Income tax expense 27,844 8,574 — 36,418 Net income $ 268,851 $ 56,148 $ — $ 324,999 Capital expenditures $ 362,468 $ 143,381 $ — $ 505,849 Three Months Ended March 31, 2021 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 1,281,826 $ 37,247 $ — $ 1,319,073 Intersegment revenues 848 116,921 (117,769) — Total operating revenues 1,282,674 154,168 (117,769) 1,319,073 Purchased gas cost 691,147 113 (117,451) 573,809 Operation and maintenance expense 123,990 32,703 (318) 156,375 Depreciation and amortization expense 85,667 32,969 — 118,636 Taxes, other than income 78,615 9,834 — 88,449 Operating income 303,255 78,549 — 381,804 Other non-operating income (expense) (760) 3,594 — 2,834 Interest charges 14,017 12,079 — 26,096 Income before income taxes 288,478 70,064 — 358,542 Income tax expense 56,142 5,646 — 61,788 Net income $ 232,336 $ 64,418 $ — $ 296,754 Capital expenditures $ 296,184 $ 92,735 $ — $ 388,919 Six Months Ended March 31, 2022 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 2,581,303 $ 81,302 $ — $ 2,662,605 Intersegment revenues 1,665 245,363 (247,028) — Total operating revenues 2,582,968 326,665 (247,028) 2,662,605 Purchased gas cost 1,490,653 (1,728) (246,384) 1,242,541 Operation and maintenance expense 244,825 78,281 (644) 322,462 Depreciation and amortization expense 189,409 71,821 — 261,230 Taxes, other than income 156,281 19,098 — 175,379 Operating income 501,800 159,193 — 660,993 Other non-operating income 2,465 11,450 — 13,915 Interest charges 23,705 25,074 — 48,779 Income before income taxes 480,560 145,569 — 626,129 Income tax expense 32,138 19,783 — 51,921 Net income $ 448,422 $ 125,786 $ — $ 574,208 Capital expenditures $ 799,850 $ 390,179 $ — $ 1,190,029 Six Months Ended March 31, 2021 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 2,157,713 $ 75,840 $ — $ 2,233,553 Intersegment revenues 1,611 238,041 (239,652) — Total operating revenues 2,159,324 313,881 (239,652) 2,233,553 Purchased gas cost 1,102,219 (1,131) (239,019) 862,069 Operation and maintenance expense 232,792 62,859 (633) 295,018 Depreciation and amortization expense 168,537 65,384 — 233,921 Taxes, other than income 142,967 18,934 — 161,901 Operating income 512,809 167,835 — 680,644 Other non-operating income 75 8,831 — 8,906 Interest charges 24,729 23,377 — 48,106 Income before income taxes 488,155 153,289 — 641,444 Income tax expense 102,127 24,885 — 127,012 Net income $ 386,028 $ 128,404 $ — $ 514,432 Capital expenditures $ 602,200 $ 243,528 $ — $ 845,728 Balance sheet information at March 31, 2022 and September 30, 2021 by segment is presented in the following tables: March 31, 2022 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Property, plant and equipment, net $ 11,960,553 $ 4,124,420 $ — $ 16,084,973 Total assets $ 20,515,446 $ 4,372,335 $ (3,616,638) $ 21,271,143 September 30, 2021 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Property, plant and equipment, net $ 11,232,649 $ 3,831,321 $ — $ 15,063,970 Total assets $ 18,847,266 $ 4,076,844 $ (3,315,448) $ 19,608,662

Earnings Per Share

Earnings Per Share	6 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share We use the two-class method of computing earnings per share because we have participating securities in the form of non-vested restricted stock units with a nonforfeitable right to dividend equivalents, for which vesting is predicated solely on the passage of time. The calculation of earnings per share using the two-class method excludes income attributable to these participating securities from the numerator and excludes the dilutive impact of those shares from the denominator. Basic weighted average shares outstanding is calculated based upon the weighted average number of common shares outstanding during the periods presented. Also, this calculation includes fully vested stock awards that have not yet been issued as common stock. Additionally, the weighted average shares outstanding for diluted EPS includes the incremental effects of the forward sale agreements, discussed in Note 7 to the unaudited condensed consolidated financial statements, when the impact is dilutive. Basic and diluted earnings per share for the three and six months ended March 31, 2022 and 2021 are calculated as follows: Three Months Ended March 31 Six Months Ended March 31 2022 2021 2022 2021 (In thousands, except per share amounts) Basic Earnings Per Share Net income $ 324,999 $ 296,754 $ 574,208 $ 514,432 Less: Income allocated to participating securities 202 199 379 350 Income available to common shareholders $ 324,797 $ 296,555 $ 573,829 $ 514,082 Basic weighted average shares outstanding 136,834 129,161 135,259 128,098 Net income per share — Basic $ 2.37 $ 2.30 $ 4.24 $ 4.01 Diluted Earnings Per Share Income available to common shareholders $ 324,797 $ 296,555 $ 573,829 $ 514,082 Effect of dilutive shares — — — — Income available to common shareholders $ 324,797 $ 296,555 $ 573,829 $ 514,082 Basic weighted average shares outstanding 136,834 129,161 135,259 128,098 Dilutive shares 416 3 211 2 Diluted weighted average shares outstanding 137,250 129,164 135,470 128,100 Net income per share - Diluted $ 2.37 $ 2.30 $ 4.24 $ 4.01

Revenue and Accounts Receivable

Revenue and Accounts Receivable	6 Months Ended
	Mar. 31, 2022
Revenue from Contract with Customer [Abstract]
Revenue and Accounts Receivable	Revenue and Accounts Receivable Revenue Our revenue recognition policy is fully described in Note 2 to the consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2021. The following tables disaggregate our revenue from contracts with customers by customer type and segment and provide a reconciliation to total operating revenues, including intersegment revenues, for the three and six months ended March 31, 2022 and 2021. Three Months Ended March 31, 2022 Three Months Ended March 31, 2021 Distribution Pipeline and Storage Distribution Pipeline and Storage (In thousands) Gas sales revenues: Residential $ 1,090,702 $ — $ 893,720 $ — Commercial 428,330 — 326,182 — Industrial 54,372 — 31,066 — Public authority and other 26,396 — 20,227 — Total gas sales revenues 1,599,800 — 1,271,195 — Transportation revenues 32,801 163,850 30,973 151,565 Miscellaneous revenues 2,680 2,284 3,325 3,878 Revenues from contracts with customers 1,635,281 166,134 1,305,493 155,443 Alternative revenue program revenues (1) (25,246) (2,387) (23,313) (1,275) Other revenues 511 — 494 — Total operating revenues $ 1,610,546 $ 163,747 $ 1,282,674 $ 154,168 Six Months Ended March 31, 2022 Six Months Ended March 31, 2021 Distribution Pipeline and Storage Distribution Pipeline and Storage (In thousands) Gas sales revenues: Residential $ 1,666,543 $ — $ 1,485,554 $ — Commercial 679,091 — 535,129 — Industrial 103,053 — 55,774 — Public authority and other 41,588 — 33,289 — Total gas sales revenues 2,490,275 — 2,109,746 — Transportation revenues 60,670 327,709 58,740 316,326 Miscellaneous revenues 5,279 8,827 5,721 9,026 Revenues from contracts with customers 2,556,224 336,536 2,174,207 325,352 Alternative revenue program revenues (1) 25,740 (9,871) (15,872) (11,471) Other revenues 1,004 — 989 — Total operating revenues $ 2,582,968 $ 326,665 $ 2,159,324 $ 313,881 (1) In our distribution segment, we have weather-normalization adjustment mechanisms that serve to mitigate the effects of weather on our revenue. Additionally, APT has a regulatory mechanism that requires that we share with its tariffed customers 75% of the difference between the total non-tariffed revenues earned during a test period and a regulatorily determined revenue benchmark. Accounts receivable and allowance for uncollectible accounts Accounts receivable arise from natural gas sales to residential, commercial, industrial, public authority and other customers. Our accounts receivable balance includes unbilled amounts which represent a customer’s consumption of gas from the date of the last cycle billing through the last day of the month. The receivable balances are short term and generally do not extend beyond one month. To minimize credit risk, we assess the credit worthiness of new customers, require deposits where necessary, assess late fees, pursue collection activities and disconnect service for nonpayment. After disconnection, accounts are written off when deemed uncollectible. Our policy related to the accounting for our allowance for uncollectible accounts is fully described in Note 2 to the consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2021. During the six months ended March 31, 2022, there were no material changes to this policy. Rollforwards of our allowance for uncollectible accounts for the three and six months ended March 31, 2022 and 2021 are presented in the table below. The allowance excludes the gas cost portion of customers’ bills for approximately 79 percent of our customers as we have the ability to collect these gas costs through our gas cost recovery mechanisms in most of our jurisdictions. Three Months Ended March 31, 2022 (In thousands) Beginning balance, December 31, 2021 $ 64,934 Current period provisions 5,705 Write-offs charged against allowance (9,029) Recoveries of amounts previously written off 603 Ending balance, March 31, 2022 $ 62,213 Three Months Ended March 31, 2021 (In thousands) Beginning balance, December 31, 2020 $ 35,089 Current period provisions 11,532 Write-offs charged against allowance (2,381) Recoveries of amounts previously written off 440 Ending balance, March 31, 2021 $ 44,680 Six Months Ended March 31, 2022 (In thousands) Beginning balance, September 30, 2021 $ 64,471 Current period provisions 12,075 Write-offs charged against allowance (15,458) Recoveries of amounts previously written off 1,125 Ending balance, March 31, 2022 $ 62,213 Six Months Ended March 31, 2021 (In thousands) Beginning balance, September 30, 2020 $ 29,949 Current period provisions 18,469 Write-offs charged against allowance (4,669) Recoveries of amounts previously written off 931 Ending balance, March 31, 2021 $ 44,680

Debt

Debt	6 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Debt	DebtThe nature and terms of our debt instruments and credit facilities are described in detail in Note 7 to the consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2021. Other than as described below, there were no material changes in the terms of our debt instruments during the six months ended March 31, 2022. Long-term debt at March 31, 2022 and September 30, 2021 consisted of the following: March 31, 2022 September 30, 2021 (In thousands) Unsecured 0.625% Senior Notes, due March 2023 $ 1,100,000 $ 1,100,000 Unsecured 3.00% Senior Notes, due 2027 500,000 500,000 Unsecured 2.625% Senior Notes, due 2029 500,000 300,000 Unsecured 1.50% Senior Notes, due 2031 600,000 600,000 Unsecured 5.95% Senior Notes, due 2034 200,000 200,000 Unsecured 5.50% Senior Notes, due 2041 400,000 400,000 Unsecured 4.15% Senior Notes, due 2043 500,000 500,000 Unsecured 4.125% Senior Notes, due 2044 750,000 750,000 Unsecured 4.30% Senior Notes, due 2048 600,000 600,000 Unsecured 4.125% Senior Notes, due 2049 450,000 450,000 Unsecured 3.375% Senior Notes, due 2049 500,000 500,000 Unsecured 2.85% Senior Notes, due 2052 600,000 — Floating-rate term loan, due April 2022 — 200,000 Floating-rate Senior Notes, due March 2023 1,100,000 1,100,000 Medium-term note Series A, 1995-1, 6.67%, due 2025 10,000 10,000 Unsecured 6.75% Debentures, due 2028 150,000 150,000 Finance lease obligations 52,537 18,739 Total long-term debt 8,012,537 7,378,739 Less: Original issue discount on unsecured senior notes and debentures 3,814 2,811 Debt issuance cost 49,724 45,271 Current maturities 2,201,404 2,400,452 $ 5,757,595 $ 4,930,205 On October 1, 2021, we completed a public offering of $600 million of 2.85% senior notes due 2052, with an effective interest rate of 2.58%, after giving effect to the offering costs and settlement of our interest rate swaps. The net proceeds from the offering, after the underwriting discount and offering expenses, of $589.8 million were used for general corporate purposes. On January 14, 2022, we completed a public offering of $200 million of 2.625% senior notes due 2029, with an effective interest rate of 2.54%, after giving effect to the offering costs. The net proceeds from the offering, after the underwriting discount and offering expenses, of $200.8 million were used to repay our $200 million floating-rate term loan on January 18, 2022. Short-term debt We utilize short-term debt to provide cost-effective, short-term financing until it can be replaced with a balance of long-term debt and equity financing that achieves the Company’s desired capital structure with an equity-to-total-capitalization ratio between 50% and 60%, inclusive of long-term and short-term debt. Our short-term borrowing requirements are driven primarily by construction work in progress and the seasonal nature of the natural gas business. Our short-term borrowing requirements are satisfied through a combination of a $1.5 billion commercial paper program and four committed revolving credit facilities with third-party lenders that provide $2.5 billion of total working capital funding. The primary source of our funding is our commercial paper program, which is supported by a five-year unsecured $1.5 billion credit facility. On March 31, 2022, we amended this agreement to (i) extend the maturity date from March 31, 2026 to March 31, 2027 and (ii) replace the London interbank offered rate (the LIBOR Rate) with the forward-looking term rate based on the secured overnight financing rate (the SOFR Rate) as the interest rate benchmark. This facility now bears interest at a base rate or at a SOFR-based rate for the applicable interest period, plus a margin ranging from zero percent to 0.25 percent for base rate advances or a margin ranging from 0.75 percent to 1.25 percent for SOFR-based advances, based on the Company’s credit ratings. Additionally, the facility contains a $250 million accordion feature, which provides the opportunity to increase the total committed loan to $1.75 billion. At March 31, 2022 and September 30, 2021, there were no amounts outstanding under our commercial paper program. We also have a $900 million three-year unsecured revolving credit facility which is used to provide additional working capital funding. On March 31, 2022, we amended this agreement to (i) extend the maturity date from March 31, 2024 to March 31, 2025 and (ii) replace the LIBOR Rate with the SOFR Rate as the interest rate benchmark. This facility now bears interest at a base rate or at a SOFR-based rate for the applicable interest period, plus a margin ranging from zero percent to 0.25 percent for base rate advances or a margin ranging from 0.75 percent to 1.25 percent for SOFR-based advances, based on the Company's credit ratings. Additionally, the facility contains a $100 million accordion feature, which provides the opportunity to increase the total committed loan to $1.0 billion. At March 31, 2022, there were no borrowings outstanding under this facility. Additionally, we have a $50 million 364-day unsecured facility, which was renewed April 1, 2022 and is used to provide working capital funding. There were no borrowings outstanding under this facility as of March 31, 2022. Finally, we have a $50 million 364-day unsecured revolving credit facility, which was renewed March 31, 2022 and is used to issue letters of credit and to provide working capital funding. At March 31, 2022, there were no borrowings outstanding under this facility; however, outstanding letters of credit reduced the total amount available to us to $44.4 million. Debt covenants The availability of funds under these credit facilities is subject to conditions specified in the respective credit agreements, all of which we currently satisfy. These conditions include our compliance with financial covenants and the continued accuracy of representations and warranties contained in these agreements. We are required by the financial covenants in each of these facilities to maintain, at the end of each fiscal quarter, a ratio of total-debt-to-total-capitalization of no greater than 70 percent. At March 31, 2022, our total-debt-to-total-capitalization ratio, as defined in the agreements, was 48 percent. In addition, both the interest margin and the fee that we pay on unused amounts under certain of these facilities are subject to adjustment depending upon our credit ratings. These credit facilities and our public indentures contain usual and customary covenants for our business, including covenants substantially limiting liens, substantial asset sales and mergers. Additionally, our public debt indentures relating to our senior notes and debentures, as well as certain of our revolving credit agreements, each contain a default provision that is triggered if outstanding indebtedness arising out of any other credit agreements in amounts ranging from in excess of $15 million to in excess of $100 million becomes due by acceleration or if not paid at maturity. We were in compliance with all of our debt covenants as of March 31, 2022. If we were unable to comply with our debt covenants, we would likely be required to repay our outstanding balances on demand, provide additional collateral or take other corrective actions.

Shareholders' Equity

Shareholders' Equity	6 Months Ended
	Mar. 31, 2022
Equity [Abstract]
Shareholders' Equity	Shareholders' EquityThe following tables present a reconciliation of changes in stockholders' equity for the three and six months ended March 31, 2022 and 2021. Common stock Additional Accumulated Retained Total Number of Stated (In thousands, except share and per share data) Balance, September 30, 2021 132,419,754 $ 662 $ 5,023,751 $ 69,803 $ 2,812,673 $ 7,906,889 Net income — — — — 249,209 249,209 Other comprehensive loss — — — (45,947) — (45,947) Cash dividends ($0.68 per share) — — — — (90,411) (90,411) Common stock issued: Public and other stock offerings 2,730,115 13 265,848 — — 265,861 Stock-based compensation plans 275,212 2 3,942 — — 3,944 Balance, December 31, 2021 135,425,081 677 5,293,541 23,856 2,971,471 8,289,545 Net income — — — — 324,999 324,999 Other comprehensive income — — — 121,723 — 121,723 Cash dividends ($0.68 per share) — — — — (93,533) (93,533) Common stock issued: Public and other stock offerings 3,509,116 18 336,451 — — 336,469 Stock-based compensation plans 77,832 — 4,028 — — 4,028 Balance, March 31, 2022 139,012,029 $ 695 $ 5,634,020 $ 145,579 $ 3,202,937 $ 8,983,231 Common stock Additional Accumulated Retained Total Number of Stated (In thousands, except share and per share data) Balance, September 30, 2020 125,882,477 $ 629 $ 4,377,149 $ (57,589) $ 2,471,014 $ 6,791,203 Net income — — — — 217,678 217,678 Other comprehensive income — — — 60,121 — 60,121 Cash dividends ($0.625 per share) — — — — (79,023) (79,023) Common stock issued: Public and other stock offerings 2,126,118 11 219,998 — — 220,009 Stock-based compensation plans 144,366 1 3,167 — — 3,168 Balance, December 31, 2020 128,152,961 641 4,600,314 2,532 2,609,669 7,213,156 Net income — — — — 296,754 296,754 Other comprehensive income — — — 137,939 — 137,939 Cash dividends ($0.625 per share) — — — — (80,325) (80,325) Common stock issued: Public and other stock offerings 2,498,026 12 248,948 — — 248,960 Stock-based compensation plans 16,122 — 4,441 — — 4,441 Balance, March 31, 2021 130,667,109 $ 653 $ 4,853,703 $ 140,471 $ 2,826,098 $ 7,820,925 Shelf Registration, At-the-Market Equity Sales Program and Equity Issuances We have a shelf registration statement with the Securities and Exchange Commission (SEC) that allows us to issue up to $5.0 billion in common stock and/or debt securities through June 29, 2024. As of the date of this report, $2.2 billion of securities were available for issuance under this shelf registration statement. On March 23, 2022, we filed a prospectus supplement under the shelf registration statement relating to an at-the-market (ATM) equity sales program under which we may issue and sell shares of our common stock up to an aggregate offering price of $1.0 billion through June 29, 2024 (including shares of common stock that may be sold pursuant to forward sale agreements entered into concurrently with the ATM equity sales program). This ATM equity sales program replaced our previous ATM equity sales program, filed on June 29, 2021, which was exhausted during our second fiscal quarter. During the six months ended March 31, 2022, we executed forward sales under our ATM equity sales program with various forward sellers who borrowed and sold 7,381,043 shares of our common stock at an aggregate price of $759.8 million. During the six months ended March 31, 2022, we also settled forward sale agreements with respect to 6,162,269 shares that had been borrowed and sold by various forward sellers under the ATM program for net proceeds of $594.3 million. As of March 31, 2022, $1.0 billion of equity was available for issuance under our existing ATM program. Additionally, we had $451.3 million in available proceeds from outstanding forward sale agreements, as detailed below. Maturity Shares Available Net Proceeds Available Forward Price September 29, 2023 4,290,498 $ 451,292 $ 105.18 Accumulated Other Comprehensive Income (Loss) We record deferred gains (losses) in AOCI related to available-for-sale debt securities and interest rate agreement cash flow hedges. Deferred gains (losses) for our available-for-sale debt securities are recognized in earnings upon settlement, while deferred gains (losses) related to our interest rate agreement cash flow hedges are recognized in earnings as they are amortized. The following tables provide the components of our accumulated other comprehensive income (loss) balances, net of the related tax effects allocated to each component of other comprehensive income (loss). Available- Interest Rate Total (In thousands) September 30, 2021 $ 47 $ 69,756 $ 69,803 Other comprehensive income (loss) before reclassifications (230) 74,518 74,288 Amounts reclassified from accumulated other comprehensive income — 1,488 1,488 Net current-period other comprehensive income (loss) (230) 76,006 75,776 March 31, 2022 $ (183) $ 145,762 $ 145,579 Available- Interest Rate Total (In thousands) September 30, 2020 $ 238 $ (57,827) $ (57,589) Other comprehensive income (loss) before reclassifications (129) 195,906 195,777 Amounts reclassified from accumulated other comprehensive income — 2,283 2,283 Net current-period other comprehensive income (loss) (129) 198,189 198,060 March 31, 2021 $ 109 $ 140,362 $ 140,471

Winter Storm Uri

Winter Storm Uri	6 Months Ended
	Mar. 31, 2022
Unusual or Infrequent Items, or Both [Abstract]
Winter Storm Uri	Winter Storm Uri Overview As described in Note 9 to the consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2021, a historic winter storm impacted supply, market pricing and demand for natural gas in our service territories in mid-February 2021. During this time, the governors of Kansas and Texas each declared a state of emergency, and certain regulatory agencies issued emergency orders that impacted the utility and natural gas industries, including statewide utilities curtailment programs and orders encouraging or requiring jurisdictional natural gas utilities to work to ensure customers were provided with safe and reliable natural gas service. Due to the historic nature of this winter storm, we experienced unforeseeable and unprecedented market pricing for gas costs, which resulted in aggregated natural gas purchases during the month of February of approximately $2.3 billion. These gas costs were paid using funds received from a public offering of debt securities completed in March 2021 of $2.2 billion. Regulatory Asset Accounting Our purchased gas costs are recoverable through purchased gas cost adjustment mechanisms in each state where we operate. Due to the unprecedented level of purchased gas costs incurred during Winter Storm Uri, the Kansas Corporation Commission (KCC) and the Railroad Commission of Texas (RRC) issued orders authorizing natural gas utilities to record a regulatory asset to account for the extraordinary costs associated with the winter storm. Pursuant to these orders, as of March 31, 2022, we have recorded a $2.1 billion regulatory asset for incremental costs, including carrying costs, incurred in Kansas ($87.9 million) and Texas ($2,018.6 million). Securitization Proceedings To minimize the impact on the customer bill by extending the recovery periods for these unprecedented purchased gas costs, the Kansas and Texas State Legislatures each enacted securitization legislation in 2021, as described in further detail in Note 9 to the consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2021. Kansas On September 14, 2021, we filed with the KCC an application to securitize $94.1 million of extraordinary gas costs incurred during Winter Storm Uri. This amount also includes an estimate of penalties, carrying costs and administrative costs that we expect to incur in connection with the resolution of this filing. On March 24, 2022, the KCC issued an Order Approving Unanimous Settlement Agreement which stipulated that all of our gas and storage costs were prudently incurred. We currently anticipate receiving a Financing Order during the first fiscal quarter of 2023. Because we intend to securitize these costs and recover over several years, we have recorded the regulatory asset for Kansas as a long-term asset in deferred charges and other assets as of March 31, 2022. Texas We filed our application with the RRC on July 30, 2021 to securitize $2.0 billion of extraordinary gas costs incurred during Winter Storm Uri. This amount also included an estimate of carrying costs and administrative costs that we expect to incur in connection with the resolution of this filing. On November 10, 2021, the RRC issued a Final Determination of the Regulatory Asset (the Final Determination). The Final Determination stipulates that all of our gas and storage costs were prudently incurred. Additionally, the Final Determination permits us to defer, through December 31, 2021 our actual carrying costs associated with the $2.2 billion of incremental financing issued in March 2021 and to recover approximately $0.6 million of our administrative costs.

Interim Pension and Other Postr

Interim Pension and Other Postretirement Benefit Plan Information	6 Months Ended
	Mar. 31, 2022
Retirement Benefits, Description [Abstract]
Interim Pension and Other Postretirement Benefit Plan Information	Interim Pension and Other Postretirement Benefit Plan InformationThe components of our net periodic pension cost for our pension and other postretirement benefit plans for the three and six months ended March 31, 2022 and 2021 are presented in the following tables. Most of these costs are recoverable through our tariff rates. A portion of these costs is capitalized into our rate base or deferred as a regulatory asset or liability. The remaining costs are recorded as a component of operation and maintenance expense or other non-operating expense. Three Months Ended March 31 Pension Benefits Other Benefits 2022 2021 2022 2021 (In thousands) Components of net periodic pension cost: Service cost $ 4,324 $ 4,613 $ 2,558 $ 4,306 Interest cost (1) 5,064 5,028 2,684 2,660 Expected return on assets (1) (7,383) (6,978) (3,313) (2,614) Amortization of prior service cost (credit) (1) (58) (58) (3,308) 43 Amortization of actuarial (gain) loss (1) 1,951 3,171 — — Net periodic pension cost $ 3,898 $ 5,776 $ (1,379) $ 4,395 Six Months Ended March 31 Pension Benefits Other Benefits 2022 2021 2022 2021 (In thousands) Components of net periodic pension cost: Service cost $ 8,647 $ 9,225 $ 5,117 $ 8,612 Interest cost (1) 10,127 10,056 5,367 5,320 Expected return on assets (1) (14,766) (13,956) (6,625) (5,228) Amortization of prior service cost (credit) (1) (116) (116) (6,617) 86 Amortization of actuarial (gain) loss (1) 3,902 6,343 — — Net periodic pension cost $ 7,794 $ 11,552 $ (2,758) $ 8,790 (1) The components of net periodic cost other than the service cost component are included in the line item other non-operating expense in the condensed consolidated statements of comprehensive income or are capitalized on the condensed consolidated balance sheets as a regulatory asset or liability, as described in Note 2 to the consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2021. For the six months ended March 31, 2022 we contributed $7.8 million to our postretirement medical plans. We anticipate contributing a total of between $15 million and $25 million to our postretirement plans during fiscal 2022.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Mar. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Litigation and Environmental Matters In the normal course of business, we are subject to various legal and regulatory proceedings. For such matters, we record liabilities when they are considered probable and estimable, based on currently available facts, our historical experience and our estimates of the ultimate outcome or resolution of the liability in the future. While the outcome of these proceedings is uncertain and a loss in excess of the amount we have accrued is possible though not reasonably estimable, it is the opinion of management that any amounts exceeding the accruals will not have a material adverse impact on our financial position, results of operations or cash flows. We maintain liability insurance for various risks associated with the operation of our natural gas pipelines and facilities, including for property damage and bodily injury. These liability insurance policies generally require us to be responsible for the first $1.0 million (self-insured retention) of each incident. The National Transportation Safety Board (NTSB) held a public meeting on January 12, 2021 to determine the probable cause of the incident that occurred at a Dallas, Texas residence on February 23, 2018 that resulted in one fatality and injuries to four other residents. At the meeting, the Board deliberated and voted on proposed findings of fact, a probable cause statement, and safety recommendations. On February 8, 2021, the NTSB issued its final report that included an Executive Summary, Findings, Probable Cause, and Recommendations. Also on February 8, 2021, safety recommendations letters were distributed to recommendation recipients, including Atmos Energy. Atmos Energy timely provided a written response on May 7, 2021. Following the release of the NTSB’s final report, the Railroad Commission of Texas (RRC) completed its safety evaluation related to the same incident finding four alleged violations and initiated an enforcement proceeding to pursue administrative penalties totaling $1.6 million. Atmos Energy is working with the RRC to resolve the alleged violations and satisfy the administrative penalties. The NTSB is investigating a worksite accident that occurred in Farmersville, Texas on June 28, 2021 that resulted in two fatalities and injuries to two others. Together with the Railroad Commission of Texas and the Pipeline and Hazardous Materials Safety Administration, Atmos Energy is a party to the investigation and in that capacity is working closely with all parties to help determine the cause of this incident. Three civil actions have been filed in Dallas, Texas against Atmos Energy and one of its contractors in response to the accident. We are a party to various other litigation and environmental-related matters or claims that have arisen in the ordinary course of our business. While the results of such litigation and response actions to such environmental-related matters or claims cannot be predicted with certainty, we continue to believe the final outcome of such litigation and matters or claims will not have a material adverse effect on our financial condition, results of operations or cash flows. Purchase Commitments Our distribution divisions maintain supply contracts with several vendors that generally cover a period of up to one year. Commitments for estimated base gas volumes are established under these contracts on a monthly basis at contractually negotiated prices. Commitments for incremental daily purchases are made as necessary during the month in accordance with the terms of the individual contract. Our Mid-Tex Division also maintains a limited number of long-term supply contracts to ensure a reliable source of gas for our customers in its service area, which obligate it to purchase specified volumes at prices indexed to natural gas hubs or fixed price contracts. These purchase commitment contracts are detailed in our Annual Report on Form 10-K for the fiscal year ended September 30, 2021. At March 31, 2022, we were committed to purchase 24.4 Bcf within one year and 3.5 Bcf within two Rate Regulatory Proceedings As of March 31, 2022, routine rate regulatory proceedings were in progress in several of our service areas, which are discussed in further detail below in Management’s Discussion and Analysis — Recent Ratemaking Developments . Except for these proceedings, there were no material changes to rate regulatory proceedings for the six months ended March 31, 2022.

Income Taxes

Income Taxes	6 Months Ended
	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income Tax Expense Our interim effective tax rates reflect the estimated annual effective tax rates for the fiscal years ended September 30, 2022 and 2021, adjusted for tax expense associated with certain discrete items. The effective tax rates for the three months ended March 31, 2022 and 2021 was 10.1% and 17.2% and for the six months ended March 31, 2022 and 2021 were 8.3% and 19.8%. These effective tax rates differ from the federal statutory tax rate of 21% primarily due to the amortization of excess deferred federal income tax liabilities, tax credits, state income taxes and other permanent book-to-tax differences. These adjustments have a relative impact on the effective tax rate proportionally to pretax income or loss. Beginning in the second quarter of fiscal 2021 and through the end of the fiscal year, we reached agreement with regulators in various states to begin refunding excess deferred tax liabilities generally over a three Regulatory Excess Deferred Taxes Regulatory excess net deferred taxes represent changes in our net deferred tax liability related to our cost of service ratemaking due to the enactment of the Tax Cuts and Jobs Act of 2017 (the "TCJA") and state tax legislative changes in Kansas and Louisiana. Currently, the regulatory excess net deferred tax liability of $578.5 million is being returned over various periods. Of this amount, $458.3 million is being returned to customers over 35 - 60 months. An additional $105.1 million is being returned to customers on a provisional basis over 15 - 69 years until our regulators establish the final refund periods. The refund of the remaining $15.1 million will be addressed in future rate proceedings. As of March 31, 2022 and September 30, 2021, $156.0 million and $155.9 million is recorded in other current liabilities. Winter Storm Uri Deferred Tax Assets and Liabilities We deduct our purchased gas costs for federal income tax purposes in the period they are paid. As a result of impacts from Winter Storm Uri, we recorded a $471.0 million (tax effected) increase in our deferred tax liability and an increase in our net operating loss carryforward as of September 30, 2021. At September 30, 2021, we had $850.2 million (tax effected) of federal net operating loss carryforwards. As a result of the Financing Order issued by the Texas RRC on February 8, 2022, we reduced the deferred tax liability associated with the Winter Storm Uri regulatory asset and the corresponding deferred tax asset associated with net operating loss carryforwards by $451.1 million during the second quarter of fiscal 2022. As of March 31, 2022, we had $438.0 million (tax effected) of federal net operating loss carryforwards. The federal net operating loss carryforwards are available to offset future taxable income. These net operating losses can be carried forward indefinitely. The Company also has $31.1 million (tax effected) of state net operating loss carryforwards (net of $8.2 million of federal effects) and $1.7 million of state tax credits carryforwards (net of $0.5 million of federal effects). Depending on the jurisdiction in which the state net operating loss was generated, the carryforwards are subject to expiration as early as 2035.

Financial Instruments

Financial Instruments	6 Months Ended
	Mar. 31, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instruments	Financial Instruments We currently use financial instruments to mitigate commodity price risk and interest rate risk. The objectives and strategies for using financial instruments and the related accounting for these financial instruments are fully described in Notes 2 and 15 to the consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2021. During the six months ended March 31, 2022, there were no material changes in our objectives, strategies and accounting for using financial instruments. Our financial instruments do not contain any credit-risk-related or other contingent features that could cause payments to be accelerated when our financial instruments are in net liability positions. The following summarizes those objectives and strategies. Commodity Risk Management Activities Our purchased gas cost adjustment mechanisms essentially insulate our distribution segment from commodity price risk; however, our customers are exposed to the effects of volatile natural gas prices. We manage this exposure through a combination of physical storage, fixed-price forward contracts and financial instruments, primarily over-the-counter swap and option contracts, in an effort to minimize the impact of natural gas price volatility on our customers during the winter heating season. We typically seek to hedge between 25 and 50 percent of anticipated heating season gas purchases using financial instruments. For the 2021-2022 heating season (generally October through March), in the jurisdictions where we are permitted to utilize financial instruments, we hedged approximately 42 percent, or 23.9 Bcf, of the winter flowing gas requirements. We have not designated these financial instruments as hedges for accounting purposes. Interest Rate Risk Management Activities We manage interest rate risk by periodically entering into financial instruments to effectively fix the Treasury yield component of the interest cost associated with anticipated financings. Quantitative Disclosures Related to Financial Instruments The following tables present detailed information concerning the impact of financial instruments on our condensed consolidated balance sheet and statements of comprehensive income. As of March 31, 2022, our financial instruments were comprised of both long and short commodity positions. A long position is a contract to purchase the commodity, while a short position is a contract to sell the commodity. As of March 31, 2022, we had 4,777 MMcf of net long commodity contracts outstanding. These contracts have not been designated as hedges. Financial Instruments on the Balance Sheet The following tables present the fair value and balance sheet classification of our financial instruments as of March 31, 2022 and September 30, 2021. The gross amounts of recognized assets and liabilities are netted within our unaudited condensed consolidated balance sheets to the extent that we have netting arrangements with our counterparties. However, as of March 31, 2022 and September 30, 2021, no gross amounts and no cash collateral were netted within our consolidated balance sheet. March 31, 2022 Balance Sheet Location Assets Liabilities (In thousands) Designated As Hedges: Interest rate contracts Other current assets / $ 109,887 $ — Interest rate contracts Deferred charges and other assets / 155,637 — Total 265,524 — Not Designated As Hedges: Commodity contracts Other current assets / 18,005 (1,113) Commodity contracts Deferred charges and other assets / — (16) Total 18,005 (1,129) Gross / Net Financial Instruments $ 283,529 $ (1,129) September 30, 2021 Balance Sheet Location Assets Liabilities (In thousands) Designated As Hedges: Interest rate contracts Deferred charges and other assets / $ 169,469 $ — Total 169,469 — Not Designated As Hedges: Commodity contracts Other current assets / 55,073 (5,269) Commodity contracts Deferred charges and other assets / 6,144 — Total 61,217 (5,269) Gross / Net Financial Instruments $ 230,686 $ (5,269) Impact of Financial Instruments on the Statement of Comprehensive Income Cash Flow Hedges As discussed above, our distribution segment has interest rate agreements, which we designated as cash flow hedges at the time the agreements were executed. The net loss on settled interest rate agreements reclassified from AOCI into interest charges on our condensed consolidated statements of comprehensive income for the three months ended March 31, 2022 and 2021 was $1.0 million and $1.5 million and for the six months ended March 31, 2022 and 2021 was $1.9 million and $2.9 million. The following table summarizes the gains and losses arising from hedging transactions that were recognized as a component of other comprehensive income (loss), net of taxes, for the three and six months ended March 31, 2022 and 2021. The amounts included in the table below exclude gains and losses arising from ineffectiveness because those amounts are immediately recognized in the statement of comprehensive income as incurred. Three Months Ended March 31 Six Months Ended March 31 2022 2021 2022 2021 (In thousands) Increase in fair value: Interest rate agreements $ 121,140 $ 136,864 $ 74,518 $ 195,906 Recognition of losses in earnings due to settlements: Interest rate agreements 744 1,141 1,488 2,283 Total other comprehensive income from hedging, net of tax $ 121,884 $ 138,005 $ 76,006 $ 198,189 Deferred gains (losses) recorded in AOCI associated with our interest rate agreements are recognized in earnings as they are amortized over the terms of the underlying debt instruments. As of March 31, 2022, we had $60.2 million of net realized losses in AOCI associated with our interest rate agreements. The following amounts, net of deferred taxes, represent the expected recognition in earnings of the deferred net losses recorded in AOCI associated with our interest rate agreements, based upon the fair values of these agreements at the date of settlement. The remaining amortization periods for these settled amounts extend through fiscal 2052. However, the table below does not include the expected recognition in earnings of our outstanding interest rate swaps as those instruments have not yet settled. Interest Rate (In thousands) Next twelve months $ (2,976) Thereafter (57,250) Total $ (60,226) Financial Instruments Not Designated as Hedges As discussed above, commodity contracts which are used in our distribution segment are not designated as hedges. However, there is no earnings impact on our distribution segment as a result of the use of these financial instruments because the gains and losses arising from the use of these financial instruments are recognized in the consolidated statement of comprehensive income as a component of purchased gas cost when the related costs are recovered through our rates and recognized in revenue. Accordingly, the impact of these financial instruments is excluded from this presentation.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements We report certain assets and liabilities at fair value, which is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). We record cash and cash equivalents, accounts receivable and accounts payable at carrying value, which substantially approximates fair value due to the short-term nature of these assets and liabilities. For other financial assets and liabilities, we primarily use quoted market prices and other observable market pricing information to minimize the use of unobservable pricing inputs in our measurements when determining fair value. The methods used to determine fair value for our assets and liabilities are fully described in Note 2 to the consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2021. During the six months ended March 31, 2022, there were no changes in these methods. Fair value measurements also apply to the valuation of our pension and postretirement plan assets. Current accounting guidance requires employers to annually disclose information about fair value measurements of the assets of a defined benefit pension or other postretirement plan. The fair value of these assets is presented in Note 10 to the consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2021. Quantitative Disclosures Financial Instruments The classification of our fair value measurements requires judgment regarding the degree to which market data is observable or corroborated by observable market data. Authoritative accounting literature establishes a fair value hierarchy that prioritizes the inputs used to measure fair value based on observable and unobservable data. The hierarchy categorizes the inputs into three levels, with the highest priority given to unadjusted quoted prices in active markets for identical assets and liabilities (Level 1), with the lowest priority given to unobservable inputs (Level 3). The following tables summarize, by level within the fair value hierarchy, our assets and liabilities that were accounted for at fair value on a recurring basis as of March 31, 2022 and September 30, 2021. Assets and liabilities are categorized in their entirety based on the lowest level of input that is significant to the fair value measurement. Quoted Significant Other Observable Inputs (Level 2) (1) Significant Netting and March 31, 2022 (In thousands) Assets: Financial instruments $ — $ 283,529 $ — $ — $ 283,529 Debt and equity securities Registered investment companies 29,729 — — — 29,729 Bond mutual funds 33,209 — — — 33,209 Bonds (2) — 34,271 — — 34,271 Money market funds — 4,610 — — 4,610 Total debt and equity securities 62,938 38,881 — — 101,819 Total assets $ 62,938 $ 322,410 $ — $ — $ 385,348 Liabilities: Financial instruments $ — $ 1,129 $ — $ — $ 1,129 Quoted Significant Other Observable Inputs (Level 2) (1) Significant Netting and September 30, 2021 (In thousands) Assets: Financial instruments $ — $ 230,686 $ — $ — $ 230,686 Debt and equity securities Registered investment companies 35,175 — — — 35,175 Bond mutual funds 34,298 — — — 34,298 Bonds (2) — 35,655 — — 35,655 Money market funds — 2,943 — — 2,943 Total debt and equity securities 69,473 38,598 — — 108,071 Total assets $ 69,473 $ 269,284 $ — $ — $ 338,757 Liabilities: Financial instruments $ — $ 5,269 $ — $ — $ 5,269 (1) Our Level 2 measurements consist of over-the-counter options and swaps, which are valued using a market-based approach in which observable market prices are adjusted for criteria specific to each instrument, such as the strike price, notional amount or basis differences, municipal and corporate bonds, which are valued based on the most recent available quoted market prices and money market funds that are valued at cost. (2) Our investments in bonds are considered available-for-sale debt securities in accordance with current accounting guidance. Debt and equity securities are comprised of our available-for-sale debt securities and our equity securities. As described in Note 2 to the consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2021, we evaluate the performance of our available-for-sale debt securities on an investment by investment basis for impairment, taking into consideration the investment’s purpose, volatility, current returns and any intent to sell the security. As of March 31, 2022, no allowance for credit losses was recorded for our available-for-sale debt securities. At March 31, 2022 and September 30, 2021, the amortized cost of our available-for-sale debt securities was $34.5 million and $35.6 million. At March 31, 2022, we maintained investments in bonds that have contractual maturity dates ranging from April 2022 through March 2025. Other Fair Value Measures Our long-term debt is recorded at carrying value. The fair value of our long-term debt, excluding finance leases, is determined using third party market value quotations, which are considered Level 1 fair value measurements for debt instruments with a recent, observable trade or Level 2 fair value measurements for debt instruments where fair value is determined using the most recent available quoted market price. The carrying value of our finance leases materially approximates fair value. The following table presents the carrying value and fair value of our long-term debt, excluding finance leases, debt issuance costs and original issue premium or discount, as of March 31, 2022 and September 30, 2021: March 31, 2022 September 30, 2021 (In thousands) Carrying Amount $ 7,960,000 $ 7,360,000 Fair Value $ 7,949,543 $ 8,086,136

Concentration of Credit Risk

Concentration of Credit Risk	6 Months Ended
	Mar. 31, 2022
Risks and Uncertainties [Abstract]
Concentration of Credit Risk	Concentration of Credit RiskInformation regarding our concentration of credit risk is disclosed in Note 17 to the consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2021. During the six months ended March 31, 2022, there were no material changes in our concentration of credit risk.

Unaudited Financial Informati_2

Unaudited Financial Information (Policies)	6 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Accounting pronouncements adopted and not yet adopted	Recently issued accounting pronouncements In November 2021, the Financial Accounting Standards Board (FASB) issued guidance which will require disclosure about government assistance in the notes to the financial statements. The amendment requires annual disclosures about transactions with a government that are accounted for by applying a grant or contribution accounting model by analogy, including information about the nature of the transactions and the related accounting policy used to account for the transactions, the line items on the balance sheet and income statement that are affected by the transactions and the significant terms and conditions of the transactions, including commitments and contingencies. The amendment is effective for us beginning October 1, 2022; however, we elected to adopt this amendment during the first quarter of fiscal 2022 as permitted by the guidance. As the guidance is related only to disclosures in the notes to the financial statements, there will be no impact on our financial position, results of operations or cash flows. In March 2020, the FASB issued optional guidance which will ease the potential burden in accounting for or recognizing the effects of reference rate reform on financial reporting. The amendments provide optional expedients and exceptions for applying U.S. GAAP to contracts, hedging relationships and other transactions affected by the cessation of the London Interbank Offered Rate (LIBOR). The amendments can be elected immediately, as of March 12, 2020, through December 31, 2022. We are currently evaluating if we will apply the optional guidance as we assess the impact of the cessation of LIBOR on our current contracts and hedging relationships and the potential impact on our financial position, results of operations and cash flows.
Regulatory assets and liabilities	Regulatory assets and liabilities Accounting principles generally accepted in the United States require cost-based, rate-regulated entities that meet certain criteria to reflect the authorized recovery of costs due to regulatory decisions in their financial statements. As a result, certain costs are permitted to be capitalized rather than expensed because they can be recovered through rates. We record certain costs as regulatory assets when future recovery through customer rates is considered probable. Regulatory liabilities are recorded when it is probable that revenues will be reduced for amounts that will be credited to customers through the ratemaking process. Substantially all of our regulatory assets are recorded as a component of other current assets and deferred charges and other assets and our regulatory liabilities are recorded as a component of other current liabilities and deferred credits and other liabilities. Deferred gas costs are recorded either in other current assets or liabilities.
Earnings per share	We use the two-class method of computing earnings per share because we have participating securities in the form of non-vested restricted stock units with a nonforfeitable right to dividend equivalents, for which vesting is predicated solely on the passage of time. The calculation of earnings per share using the two-class method excludes income attributable to these participating securities from the numerator and excludes the dilutive impact of those shares from the denominator. Basic weighted average shares outstanding is calculated based upon the weighted average number of common shares outstanding during the periods presented. Also, this calculation includes fully vested stock awards that have not yet been issued as common stock. Additionally, the weighted average shares outstanding for diluted EPS includes the incremental effects of the forward sale agreements, discussed in Note 7 to the unaudited condensed consolidated financial statements, when the impact is dilutive.
Fair value measurement	Fair Value MeasurementsWe report certain assets and liabilities at fair value, which is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). We record cash and cash equivalents, accounts receivable and accounts payable at carrying value, which substantially approximates fair value due to the short-term nature of these assets and liabilities. For other financial assets and liabilities, we primarily use quoted market prices and other observable market pricing information to minimize the use of unobservable pricing inputs in our measurements when determining fair value. The methods used to determine fair value for our assets and liabilities are fully described in Note 2 to the consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2021. During the six months ended March 31, 2022, there were no changes in these methods.

Unaudited Financial Informati_3

Unaudited Financial Information (Tables)	6 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Schedule of Regulatory Assets	Significant regulatory assets and liabilities as of March 31, 2022 and September 30, 2021 included the following: March 31, September 30, (In thousands) Regulatory assets: Pension and postretirement benefit costs $ 37,927 $ 45,922 Infrastructure mechanisms (1) 204,915 222,795 Winter Storm Uri incremental costs (2) 2,106,521 2,100,728 Deferred gas costs 21,366 66,395 Regulatory excess deferred taxes 48,352 45,370 Recoverable loss on reacquired debt 3,521 3,789 Deferred pipeline record collection costs 34,149 32,099 Other 18,794 4,343 $ 2,475,545 $ 2,521,441 Regulatory liabilities: Regulatory excess deferred taxes $ 626,874 $ 705,084 Regulatory cost of removal obligation 552,100 541,511 Deferred gas costs 83,834 52,553 Asset retirement obligation 18,373 18,373 APT annual adjustment mechanism 27,397 31,110 Pension and postretirement benefit costs 53,370 56,201 Other 27,571 19,363 $ 1,389,519 $ 1,424,195 (1) Infrastructure mechanisms in Texas, Louisiana and Tennessee allow for the deferral of all eligible expenses associated with capital expenditures incurred pursuant to these rules, including the recording of interest on deferred expenses until the next rate proceeding (rate case or annual rate filing), at which time investment and costs would be recoverable through base rates. (2) Includes extraordinary gas costs subject to securitization incurred during Winter Storm Uri and permissible carrying costs. See Note 8 to the unaudited condensed consolidated financial statements for further information. This amount is recorded within other current assets and deferred charges and other assets on the condensed consolidated balance sheet as of March 31, 2022.
Schedule of Regulatory Liabilities	Significant regulatory assets and liabilities as of March 31, 2022 and September 30, 2021 included the following: March 31, September 30, (In thousands) Regulatory assets: Pension and postretirement benefit costs $ 37,927 $ 45,922 Infrastructure mechanisms (1) 204,915 222,795 Winter Storm Uri incremental costs (2) 2,106,521 2,100,728 Deferred gas costs 21,366 66,395 Regulatory excess deferred taxes 48,352 45,370 Recoverable loss on reacquired debt 3,521 3,789 Deferred pipeline record collection costs 34,149 32,099 Other 18,794 4,343 $ 2,475,545 $ 2,521,441 Regulatory liabilities: Regulatory excess deferred taxes $ 626,874 $ 705,084 Regulatory cost of removal obligation 552,100 541,511 Deferred gas costs 83,834 52,553 Asset retirement obligation 18,373 18,373 APT annual adjustment mechanism 27,397 31,110 Pension and postretirement benefit costs 53,370 56,201 Other 27,571 19,363 $ 1,389,519 $ 1,424,195 (1) Infrastructure mechanisms in Texas, Louisiana and Tennessee allow for the deferral of all eligible expenses associated with capital expenditures incurred pursuant to these rules, including the recording of interest on deferred expenses until the next rate proceeding (rate case or annual rate filing), at which time investment and costs would be recoverable through base rates. (2) Includes extraordinary gas costs subject to securitization incurred during Winter Storm Uri and permissible carrying costs. See Note 8 to the unaudited condensed consolidated financial statements for further information. This amount is recorded within other current assets and deferred charges and other assets on the condensed consolidated balance sheet as of March 31, 2022.

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Mar. 31, 2022
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Income statements and capital expenditures for the three and six months ended March 31, 2022 and 2021 by segment are presented in the following tables: Three Months Ended March 31, 2022 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 1,609,667 $ 40,152 $ — $ 1,649,819 Intersegment revenues 879 123,595 (124,474) — Total operating revenues 1,610,546 163,747 (124,474) 1,649,819 Purchased gas cost 993,854 1,683 (124,159) 871,378 Operation and maintenance expense 121,541 42,126 (315) 163,352 Depreciation and amortization expense 96,612 36,762 — 133,374 Taxes, other than income 87,236 9,347 — 96,583 Operating income 311,303 73,829 — 385,132 Other non-operating income 549 4,664 — 5,213 Interest charges 15,157 13,771 — 28,928 Income before income taxes 296,695 64,722 — 361,417 Income tax expense 27,844 8,574 — 36,418 Net income $ 268,851 $ 56,148 $ — $ 324,999 Capital expenditures $ 362,468 $ 143,381 $ — $ 505,849 Three Months Ended March 31, 2021 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 1,281,826 $ 37,247 $ — $ 1,319,073 Intersegment revenues 848 116,921 (117,769) — Total operating revenues 1,282,674 154,168 (117,769) 1,319,073 Purchased gas cost 691,147 113 (117,451) 573,809 Operation and maintenance expense 123,990 32,703 (318) 156,375 Depreciation and amortization expense 85,667 32,969 — 118,636 Taxes, other than income 78,615 9,834 — 88,449 Operating income 303,255 78,549 — 381,804 Other non-operating income (expense) (760) 3,594 — 2,834 Interest charges 14,017 12,079 — 26,096 Income before income taxes 288,478 70,064 — 358,542 Income tax expense 56,142 5,646 — 61,788 Net income $ 232,336 $ 64,418 $ — $ 296,754 Capital expenditures $ 296,184 $ 92,735 $ — $ 388,919 Six Months Ended March 31, 2022 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 2,581,303 $ 81,302 $ — $ 2,662,605 Intersegment revenues 1,665 245,363 (247,028) — Total operating revenues 2,582,968 326,665 (247,028) 2,662,605 Purchased gas cost 1,490,653 (1,728) (246,384) 1,242,541 Operation and maintenance expense 244,825 78,281 (644) 322,462 Depreciation and amortization expense 189,409 71,821 — 261,230 Taxes, other than income 156,281 19,098 — 175,379 Operating income 501,800 159,193 — 660,993 Other non-operating income 2,465 11,450 — 13,915 Interest charges 23,705 25,074 — 48,779 Income before income taxes 480,560 145,569 — 626,129 Income tax expense 32,138 19,783 — 51,921 Net income $ 448,422 $ 125,786 $ — $ 574,208 Capital expenditures $ 799,850 $ 390,179 $ — $ 1,190,029 Six Months Ended March 31, 2021 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 2,157,713 $ 75,840 $ — $ 2,233,553 Intersegment revenues 1,611 238,041 (239,652) — Total operating revenues 2,159,324 313,881 (239,652) 2,233,553 Purchased gas cost 1,102,219 (1,131) (239,019) 862,069 Operation and maintenance expense 232,792 62,859 (633) 295,018 Depreciation and amortization expense 168,537 65,384 — 233,921 Taxes, other than income 142,967 18,934 — 161,901 Operating income 512,809 167,835 — 680,644 Other non-operating income 75 8,831 — 8,906 Interest charges 24,729 23,377 — 48,106 Income before income taxes 488,155 153,289 — 641,444 Income tax expense 102,127 24,885 — 127,012 Net income $ 386,028 $ 128,404 $ — $ 514,432 Capital expenditures $ 602,200 $ 243,528 $ — $ 845,728 Balance sheet information at March 31, 2022 and September 30, 2021 by segment is presented in the following tables: March 31, 2022 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Property, plant and equipment, net $ 11,960,553 $ 4,124,420 $ — $ 16,084,973 Total assets $ 20,515,446 $ 4,372,335 $ (3,616,638) $ 21,271,143 September 30, 2021 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Property, plant and equipment, net $ 11,232,649 $ 3,831,321 $ — $ 15,063,970 Total assets $ 18,847,266 $ 4,076,844 $ (3,315,448) $ 19,608,662

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	Basic and diluted earnings per share for the three and six months ended March 31, 2022 and 2021 are calculated as follows: Three Months Ended March 31 Six Months Ended March 31 2022 2021 2022 2021 (In thousands, except per share amounts) Basic Earnings Per Share Net income $ 324,999 $ 296,754 $ 574,208 $ 514,432 Less: Income allocated to participating securities 202 199 379 350 Income available to common shareholders $ 324,797 $ 296,555 $ 573,829 $ 514,082 Basic weighted average shares outstanding 136,834 129,161 135,259 128,098 Net income per share — Basic $ 2.37 $ 2.30 $ 4.24 $ 4.01 Diluted Earnings Per Share Income available to common shareholders $ 324,797 $ 296,555 $ 573,829 $ 514,082 Effect of dilutive shares — — — — Income available to common shareholders $ 324,797 $ 296,555 $ 573,829 $ 514,082 Basic weighted average shares outstanding 136,834 129,161 135,259 128,098 Dilutive shares 416 3 211 2 Diluted weighted average shares outstanding 137,250 129,164 135,470 128,100 Net income per share - Diluted $ 2.37 $ 2.30 $ 4.24 $ 4.01

Revenue and Accounts Receivab_2

Revenue and Accounts Receivable (Tables)	6 Months Ended
	Mar. 31, 2022
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following tables disaggregate our revenue from contracts with customers by customer type and segment and provide a reconciliation to total operating revenues, including intersegment revenues, for the three and six months ended March 31, 2022 and 2021. Three Months Ended March 31, 2022 Three Months Ended March 31, 2021 Distribution Pipeline and Storage Distribution Pipeline and Storage (In thousands) Gas sales revenues: Residential $ 1,090,702 $ — $ 893,720 $ — Commercial 428,330 — 326,182 — Industrial 54,372 — 31,066 — Public authority and other 26,396 — 20,227 — Total gas sales revenues 1,599,800 — 1,271,195 — Transportation revenues 32,801 163,850 30,973 151,565 Miscellaneous revenues 2,680 2,284 3,325 3,878 Revenues from contracts with customers 1,635,281 166,134 1,305,493 155,443 Alternative revenue program revenues (1) (25,246) (2,387) (23,313) (1,275) Other revenues 511 — 494 — Total operating revenues $ 1,610,546 $ 163,747 $ 1,282,674 $ 154,168 Six Months Ended March 31, 2022 Six Months Ended March 31, 2021 Distribution Pipeline and Storage Distribution Pipeline and Storage (In thousands) Gas sales revenues: Residential $ 1,666,543 $ — $ 1,485,554 $ — Commercial 679,091 — 535,129 — Industrial 103,053 — 55,774 — Public authority and other 41,588 — 33,289 — Total gas sales revenues 2,490,275 — 2,109,746 — Transportation revenues 60,670 327,709 58,740 316,326 Miscellaneous revenues 5,279 8,827 5,721 9,026 Revenues from contracts with customers 2,556,224 336,536 2,174,207 325,352 Alternative revenue program revenues (1) 25,740 (9,871) (15,872) (11,471) Other revenues 1,004 — 989 — Total operating revenues $ 2,582,968 $ 326,665 $ 2,159,324 $ 313,881 (1) In our distribution segment, we have weather-normalization adjustment mechanisms that serve to mitigate the effects of weather on our revenue. Additionally, APT has a regulatory mechanism that requires that we share with its tariffed customers 75% of the difference between the total non-tariffed revenues earned during a test period and a regulatorily determined revenue benchmark.
Allowance for Credit Loss Activity	Rollforwards of our allowance for uncollectible accounts for the three and six months ended March 31, 2022 and 2021 are presented in the table below. The allowance excludes the gas cost portion of customers’ bills for approximately 79 percent of our customers as we have the ability to collect these gas costs through our gas cost recovery mechanisms in most of our jurisdictions. Three Months Ended March 31, 2022 (In thousands) Beginning balance, December 31, 2021 $ 64,934 Current period provisions 5,705 Write-offs charged against allowance (9,029) Recoveries of amounts previously written off 603 Ending balance, March 31, 2022 $ 62,213 Three Months Ended March 31, 2021 (In thousands) Beginning balance, December 31, 2020 $ 35,089 Current period provisions 11,532 Write-offs charged against allowance (2,381) Recoveries of amounts previously written off 440 Ending balance, March 31, 2021 $ 44,680 Six Months Ended March 31, 2022 (In thousands) Beginning balance, September 30, 2021 $ 64,471 Current period provisions 12,075 Write-offs charged against allowance (15,458) Recoveries of amounts previously written off 1,125 Ending balance, March 31, 2022 $ 62,213 Six Months Ended March 31, 2021 (In thousands) Beginning balance, September 30, 2020 $ 29,949 Current period provisions 18,469 Write-offs charged against allowance (4,669) Recoveries of amounts previously written off 931 Ending balance, March 31, 2021 $ 44,680

Debt (Tables)

Debt (Tables)	6 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	Long-term debt at March 31, 2022 and September 30, 2021 consisted of the following: March 31, 2022 September 30, 2021 (In thousands) Unsecured 0.625% Senior Notes, due March 2023 $ 1,100,000 $ 1,100,000 Unsecured 3.00% Senior Notes, due 2027 500,000 500,000 Unsecured 2.625% Senior Notes, due 2029 500,000 300,000 Unsecured 1.50% Senior Notes, due 2031 600,000 600,000 Unsecured 5.95% Senior Notes, due 2034 200,000 200,000 Unsecured 5.50% Senior Notes, due 2041 400,000 400,000 Unsecured 4.15% Senior Notes, due 2043 500,000 500,000 Unsecured 4.125% Senior Notes, due 2044 750,000 750,000 Unsecured 4.30% Senior Notes, due 2048 600,000 600,000 Unsecured 4.125% Senior Notes, due 2049 450,000 450,000 Unsecured 3.375% Senior Notes, due 2049 500,000 500,000 Unsecured 2.85% Senior Notes, due 2052 600,000 — Floating-rate term loan, due April 2022 — 200,000 Floating-rate Senior Notes, due March 2023 1,100,000 1,100,000 Medium-term note Series A, 1995-1, 6.67%, due 2025 10,000 10,000 Unsecured 6.75% Debentures, due 2028 150,000 150,000 Finance lease obligations 52,537 18,739 Total long-term debt 8,012,537 7,378,739 Less: Original issue discount on unsecured senior notes and debentures 3,814 2,811 Debt issuance cost 49,724 45,271 Current maturities 2,201,404 2,400,452 $ 5,757,595 $ 4,930,205

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	6 Months Ended
	Mar. 31, 2022
Equity [Abstract]
Reconciliation of Changes in Stockholders Equity	The following tables present a reconciliation of changes in stockholders' equity for the three and six months ended March 31, 2022 and 2021. Common stock Additional Accumulated Retained Total Number of Stated (In thousands, except share and per share data) Balance, September 30, 2021 132,419,754 $ 662 $ 5,023,751 $ 69,803 $ 2,812,673 $ 7,906,889 Net income — — — — 249,209 249,209 Other comprehensive loss — — — (45,947) — (45,947) Cash dividends ($0.68 per share) — — — — (90,411) (90,411) Common stock issued: Public and other stock offerings 2,730,115 13 265,848 — — 265,861 Stock-based compensation plans 275,212 2 3,942 — — 3,944 Balance, December 31, 2021 135,425,081 677 5,293,541 23,856 2,971,471 8,289,545 Net income — — — — 324,999 324,999 Other comprehensive income — — — 121,723 — 121,723 Cash dividends ($0.68 per share) — — — — (93,533) (93,533) Common stock issued: Public and other stock offerings 3,509,116 18 336,451 — — 336,469 Stock-based compensation plans 77,832 — 4,028 — — 4,028 Balance, March 31, 2022 139,012,029 $ 695 $ 5,634,020 $ 145,579 $ 3,202,937 $ 8,983,231 Common stock Additional Accumulated Retained Total Number of Stated (In thousands, except share and per share data) Balance, September 30, 2020 125,882,477 $ 629 $ 4,377,149 $ (57,589) $ 2,471,014 $ 6,791,203 Net income — — — — 217,678 217,678 Other comprehensive income — — — 60,121 — 60,121 Cash dividends ($0.625 per share) — — — — (79,023) (79,023) Common stock issued: Public and other stock offerings 2,126,118 11 219,998 — — 220,009 Stock-based compensation plans 144,366 1 3,167 — — 3,168 Balance, December 31, 2020 128,152,961 641 4,600,314 2,532 2,609,669 7,213,156 Net income — — — — 296,754 296,754 Other comprehensive income — — — 137,939 — 137,939 Cash dividends ($0.625 per share) — — — — (80,325) (80,325) Common stock issued: Public and other stock offerings 2,498,026 12 248,948 — — 248,960 Stock-based compensation plans 16,122 — 4,441 — — 4,441 Balance, March 31, 2021 130,667,109 $ 653 $ 4,853,703 $ 140,471 $ 2,826,098 $ 7,820,925
Summary of Forward Sales Agreements	Additionally, we had $451.3 million in available proceeds from outstanding forward sale agreements, as detailed below. Maturity Shares Available Net Proceeds Available Forward Price September 29, 2023 4,290,498 $ 451,292 $ 105.18
Schedule of Accumulated Other Comprehensive Income (Loss)	The following tables provide the components of our accumulated other comprehensive income (loss) balances, net of the related tax effects allocated to each component of other comprehensive income (loss). Available- Interest Rate Total (In thousands) September 30, 2021 $ 47 $ 69,756 $ 69,803 Other comprehensive income (loss) before reclassifications (230) 74,518 74,288 Amounts reclassified from accumulated other comprehensive income — 1,488 1,488 Net current-period other comprehensive income (loss) (230) 76,006 75,776 March 31, 2022 $ (183) $ 145,762 $ 145,579 Available- Interest Rate Total (In thousands) September 30, 2020 $ 238 $ (57,827) $ (57,589) Other comprehensive income (loss) before reclassifications (129) 195,906 195,777 Amounts reclassified from accumulated other comprehensive income — 2,283 2,283 Net current-period other comprehensive income (loss) (129) 198,189 198,060 March 31, 2021 $ 109 $ 140,362 $ 140,471

Interim Pension and Other Pos_2

Interim Pension and Other Postretirement Benefit Plan Information (Table)	6 Months Ended
	Mar. 31, 2022
Retirement Benefits, Description [Abstract]
Schedule of Net Benefit Costs	The components of our net periodic pension cost for our pension and other postretirement benefit plans for the three and six months ended March 31, 2022 and 2021 are presented in the following tables. Most of these costs are recoverable through our tariff rates. A portion of these costs is capitalized into our rate base or deferred as a regulatory asset or liability. The remaining costs are recorded as a component of operation and maintenance expense or other non-operating expense. Three Months Ended March 31 Pension Benefits Other Benefits 2022 2021 2022 2021 (In thousands) Components of net periodic pension cost: Service cost $ 4,324 $ 4,613 $ 2,558 $ 4,306 Interest cost (1) 5,064 5,028 2,684 2,660 Expected return on assets (1) (7,383) (6,978) (3,313) (2,614) Amortization of prior service cost (credit) (1) (58) (58) (3,308) 43 Amortization of actuarial (gain) loss (1) 1,951 3,171 — — Net periodic pension cost $ 3,898 $ 5,776 $ (1,379) $ 4,395 Six Months Ended March 31 Pension Benefits Other Benefits 2022 2021 2022 2021 (In thousands) Components of net periodic pension cost: Service cost $ 8,647 $ 9,225 $ 5,117 $ 8,612 Interest cost (1) 10,127 10,056 5,367 5,320 Expected return on assets (1) (14,766) (13,956) (6,625) (5,228) Amortization of prior service cost (credit) (1) (116) (116) (6,617) 86 Amortization of actuarial (gain) loss (1) 3,902 6,343 — — Net periodic pension cost $ 7,794 $ 11,552 $ (2,758) $ 8,790 (1) The components of net periodic cost other than the service cost component are included in the line item other non-operating expense in the condensed consolidated statements of comprehensive income or are capitalized on the condensed consolidated balance sheets as a regulatory asset or liability, as described in Note 2 to the consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2021.

Financial Instruments (Table)

Financial Instruments (Table)	6 Months Ended
	Mar. 31, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	The following tables present the fair value and balance sheet classification of our financial instruments as of March 31, 2022 and September 30, 2021. The gross amounts of recognized assets and liabilities are netted within our unaudited condensed consolidated balance sheets to the extent that we have netting arrangements with our counterparties. However, as of March 31, 2022 and September 30, 2021, no gross amounts and no cash collateral were netted within our consolidated balance sheet. March 31, 2022 Balance Sheet Location Assets Liabilities (In thousands) Designated As Hedges: Interest rate contracts Other current assets / $ 109,887 $ — Interest rate contracts Deferred charges and other assets / 155,637 — Total 265,524 — Not Designated As Hedges: Commodity contracts Other current assets / 18,005 (1,113) Commodity contracts Deferred charges and other assets / — (16) Total 18,005 (1,129) Gross / Net Financial Instruments $ 283,529 $ (1,129) September 30, 2021 Balance Sheet Location Assets Liabilities (In thousands) Designated As Hedges: Interest rate contracts Deferred charges and other assets / $ 169,469 $ — Total 169,469 — Not Designated As Hedges: Commodity contracts Other current assets / 55,073 (5,269) Commodity contracts Deferred charges and other assets / 6,144 — Total 61,217 (5,269) Gross / Net Financial Instruments $ 230,686 $ (5,269)
Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss)	The following table summarizes the gains and losses arising from hedging transactions that were recognized as a component of other comprehensive income (loss), net of taxes, for the three and six months ended March 31, 2022 and 2021. The amounts included in the table below exclude gains and losses arising from ineffectiveness because those amounts are immediately recognized in the statement of comprehensive income as incurred. Three Months Ended March 31 Six Months Ended March 31 2022 2021 2022 2021 (In thousands) Increase in fair value: Interest rate agreements $ 121,140 $ 136,864 $ 74,518 $ 195,906 Recognition of losses in earnings due to settlements: Interest rate agreements 744 1,141 1,488 2,283 Total other comprehensive income from hedging, net of tax $ 121,884 $ 138,005 $ 76,006 $ 198,189
Schedule of Expected Deferred Gains (Losses) Recognition	The following amounts, net of deferred taxes, represent the expected recognition in earnings of the deferred net losses recorded in AOCI associated with our interest rate agreements, based upon the fair values of these agreements at the date of settlement. The remaining amortization periods for these settled amounts extend through fiscal 2052. However, the table below does not include the expected recognition in earnings of our outstanding interest rate swaps as those instruments have not yet settled. Interest Rate (In thousands) Next twelve months $ (2,976) Thereafter (57,250) Total $ (60,226)

Fair Value Measurements (Table)

Fair Value Measurements (Table)	6 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following tables summarize, by level within the fair value hierarchy, our assets and liabilities that were accounted for at fair value on a recurring basis as of March 31, 2022 and September 30, 2021. Assets and liabilities are categorized in their entirety based on the lowest level of input that is significant to the fair value measurement. Quoted Significant Other Observable Inputs (Level 2) (1) Significant Netting and March 31, 2022 (In thousands) Assets: Financial instruments $ — $ 283,529 $ — $ — $ 283,529 Debt and equity securities Registered investment companies 29,729 — — — 29,729 Bond mutual funds 33,209 — — — 33,209 Bonds (2) — 34,271 — — 34,271 Money market funds — 4,610 — — 4,610 Total debt and equity securities 62,938 38,881 — — 101,819 Total assets $ 62,938 $ 322,410 $ — $ — $ 385,348 Liabilities: Financial instruments $ — $ 1,129 $ — $ — $ 1,129 Quoted Significant Other Observable Inputs (Level 2) (1) Significant Netting and September 30, 2021 (In thousands) Assets: Financial instruments $ — $ 230,686 $ — $ — $ 230,686 Debt and equity securities Registered investment companies 35,175 — — — 35,175 Bond mutual funds 34,298 — — — 34,298 Bonds (2) — 35,655 — — 35,655 Money market funds — 2,943 — — 2,943 Total debt and equity securities 69,473 38,598 — — 108,071 Total assets $ 69,473 $ 269,284 $ — $ — $ 338,757 Liabilities: Financial instruments $ — $ 5,269 $ — $ — $ 5,269 (1) Our Level 2 measurements consist of over-the-counter options and swaps, which are valued using a market-based approach in which observable market prices are adjusted for criteria specific to each instrument, such as the strike price, notional amount or basis differences, municipal and corporate bonds, which are valued based on the most recent available quoted market prices and money market funds that are valued at cost. (2) Our investments in bonds are considered available-for-sale debt securities in accordance with current accounting guidance.
Schedule of Carrying Values and Estimated Fair Values of Long-Term Debt	The following table presents the carrying value and fair value of our long-term debt, excluding finance leases, debt issuance costs and original issue premium or discount, as of March 31, 2022 and September 30, 2021: March 31, 2022 September 30, 2021 (In thousands) Carrying Amount $ 7,960,000 $ 7,360,000 Fair Value $ 7,949,543 $ 8,086,136

Nature of Business (Details)

Nature of Business (Details) customer in Millions	Mar. 31, 2022stateregulated_distribution_divisioncustomer
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of customers serviced | customer	3
Number of regulated distribution divisions | regulated_distribution_division	6
Number of states with service areas | state	8

Unaudited Financial Informati_4

Unaudited Financial Information - Regulatory Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Regulatory Asset [Line Items]
Regulatory assets	$ 2,475,545	$ 2,521,441
Regulatory Liabilities [Line Items]
Regulatory liabilities	1,389,519	1,424,195
Regulatory excess deferred taxes
Regulatory Liabilities [Line Items]
Regulatory liabilities	626,874	705,084
Regulatory cost of removal obligation
Regulatory Liabilities [Line Items]
Regulatory liabilities	552,100	541,511
Deferred gas costs
Regulatory Liabilities [Line Items]
Regulatory liabilities	83,834	52,553
Asset retirement obligation
Regulatory Liabilities [Line Items]
Regulatory liabilities	18,373	18,373
APT annual adjustment mechanism
Regulatory Liabilities [Line Items]
Regulatory liabilities	27,397	31,110
Pension and postretirement benefit costs
Regulatory Liabilities [Line Items]
Regulatory liabilities	53,370	56,201
Other
Regulatory Liabilities [Line Items]
Regulatory liabilities	27,571	19,363
Pension and postretirement benefit costs
Regulatory Asset [Line Items]
Regulatory assets	37,927	45,922
Infrastructure mechanisms
Regulatory Asset [Line Items]
Regulatory assets	204,915	222,795
Winter Storm Uri incremental costs
Regulatory Asset [Line Items]
Regulatory assets	2,106,521	2,100,728
Deferred gas costs
Regulatory Asset [Line Items]
Regulatory assets	21,366	66,395
Regulatory excess deferred taxes
Regulatory Asset [Line Items]
Regulatory assets	48,352	45,370
Recoverable loss on reacquired debt
Regulatory Asset [Line Items]
Regulatory assets	3,521	3,789
Deferred pipeline record collection costs
Regulatory Asset [Line Items]
Regulatory assets	34,149	32,099
Other
Regulatory Asset [Line Items]
Regulatory assets	$ 18,794	$ 4,343

Segment Information (Details)

Segment Information (Details) $ in Thousands	3 Months Ended				6 Months Ended
	Mar. 31, 2022USD ($)state	Dec. 31, 2021USD ($)	Mar. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Mar. 31, 2022USD ($)state	Mar. 31, 2021USD ($)	Sep. 30, 2021USD ($)
Segment Reporting Information [Line Items]
Number of states with service areas | state	8				8
Segment Reporting Information Profit Loss [Abstract]
Operating revenues	$ 1,649,819		$ 1,319,073		$ 2,662,605	$ 2,233,553
Purchased gas cost	871,378		573,809		1,242,541	862,069
Operation and maintenance expense	163,352		156,375		322,462	295,018
Depreciation and amortization expense	133,374		118,636		261,230	233,921
Taxes, other than income	96,583		88,449		175,379	161,901
Operating income	385,132		381,804		660,993	680,644
Other non-operating income	5,213		2,834		13,915	8,906
Interest charges	28,928		26,096		48,779	48,106
Income before income taxes	361,417		358,542		626,129	641,444
Income tax expense	36,418		61,788		51,921	127,012
Net income	324,999	$ 249,209	296,754	$ 217,678	574,208	514,432
Capital expenditures	505,849		388,919		1,190,029	845,728
Segment Reporting Information, Balance Sheet [Abstract]
Property, plant and equipment, net	16,084,973				16,084,973		$ 15,063,970
Total assets	21,271,143				21,271,143		19,608,662
Distribution
Segment Reporting Information Profit Loss [Abstract]
Operating revenues	1,609,667		1,281,826		2,581,303	2,157,713
Pipeline and Storage
Segment Reporting Information Profit Loss [Abstract]
Operating revenues	40,152		37,247		81,302	75,840
Eliminations
Segment Reporting Information Profit Loss [Abstract]
Operating revenues	(124,474)		(117,769)		(247,028)	(239,652)
Purchased gas cost	(124,159)		(117,451)		(246,384)	(239,019)
Operation and maintenance expense	(315)		(318)		(644)	(633)
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
Capital expenditures	0		0		0	0
Segment Reporting Information, Balance Sheet [Abstract]
Property, plant and equipment, net	0				0		0
Total assets	(3,616,638)				(3,616,638)		(3,315,448)
Eliminations | Distribution
Segment Reporting Information Profit Loss [Abstract]
Operating revenues	879		848		1,665	1,611
Eliminations | Pipeline and Storage
Segment Reporting Information Profit Loss [Abstract]
Operating revenues	123,595		116,921		245,363	238,041
Operating Segments | Distribution
Segment Reporting Information Profit Loss [Abstract]
Operating revenues	1,610,546		1,282,674		2,582,968	2,159,324
Purchased gas cost	993,854		691,147		1,490,653	1,102,219
Operation and maintenance expense	121,541		123,990		244,825	232,792
Depreciation and amortization expense	96,612		85,667		189,409	168,537
Taxes, other than income	87,236		78,615		156,281	142,967
Operating income	311,303		303,255		501,800	512,809
Other non-operating income	549		(760)		2,465	75
Interest charges	15,157		14,017		23,705	24,729
Income before income taxes	296,695		288,478		480,560	488,155
Income tax expense	27,844		56,142		32,138	102,127
Net income	268,851		232,336		448,422	386,028
Capital expenditures	362,468		296,184		799,850	602,200
Segment Reporting Information, Balance Sheet [Abstract]
Property, plant and equipment, net	11,960,553				11,960,553		11,232,649
Total assets	20,515,446				20,515,446		18,847,266
Operating Segments | Pipeline and Storage
Segment Reporting Information Profit Loss [Abstract]
Operating revenues	163,747		154,168		326,665	313,881
Purchased gas cost	1,683		113		(1,728)	(1,131)
Operation and maintenance expense	42,126		32,703		78,281	62,859
Depreciation and amortization expense	36,762		32,969		71,821	65,384
Taxes, other than income	9,347		9,834		19,098	18,934
Operating income	73,829		78,549		159,193	167,835
Other non-operating income	4,664		3,594		11,450	8,831
Interest charges	13,771		12,079		25,074	23,377
Income before income taxes	64,722		70,064		145,569	153,289
Income tax expense	8,574		5,646		19,783	24,885
Net income	56,148		64,418		125,786	128,404
Capital expenditures	143,381		$ 92,735		390,179	$ 243,528
Segment Reporting Information, Balance Sheet [Abstract]
Property, plant and equipment, net	4,124,420				4,124,420		3,831,321
Total assets	$ 4,372,335				$ 4,372,335		$ 4,076,844

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2022	Mar. 31, 2021
Basic Earnings Per Share
Net income	$ 324,999	$ 249,209	$ 296,754	$ 217,678	$ 574,208	$ 514,432
Less: Income allocated to participating securities	202		199		379	350
Income available to common shareholders	$ 324,797		$ 296,555		$ 573,829	$ 514,082
Basic weighted average shares outstanding (in shares)	136,834		129,161		135,259	128,098
Net income per share - basic (USD per share)	$ 2.37		$ 2.30		$ 4.24	$ 4.01
Diluted Earnings Per Share
Income available to common shareholders	$ 324,797		$ 296,555		$ 573,829	$ 514,082
Effect of dilutive shares	0		0		0	0
Income available to common shareholders	$ 324,797		$ 296,555		$ 573,829	$ 514,082
Basic weighted average shares outstanding (in shares)	136,834		129,161		135,259	128,098
Dilutive shares (in shares)	416		3		211	2
Diluted weighted average shares outstanding (in shares)	137,250		129,164		135,470	128,100
Net income per share - diluted (USD per share)	$ 2.37		$ 2.30		$ 4.24	$ 4.01

Revenue and Accounts Receivab_3

Revenue and Accounts Receivable - Disaggregation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 1,649,819	$ 1,319,073	$ 2,662,605	$ 2,233,553
Distribution
Disaggregation of Revenue [Line Items]
Total operating revenues	1,609,667	1,281,826	$ 2,581,303	2,157,713
Regulatory mechanism threshold (in percent)			75.00%
Pipeline and Storage
Disaggregation of Revenue [Line Items]
Total operating revenues	40,152	37,247	$ 81,302	75,840
Operating Segments | Distribution
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,635,281	1,305,493	2,556,224	2,174,207
Alternative revenue program revenues	(25,246)	(23,313)	25,740	(15,872)
Other revenues	511	494	1,004	989
Total operating revenues	1,610,546	1,282,674	2,582,968	2,159,324
Operating Segments | Distribution | Gas sales revenues:
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,599,800	1,271,195	2,490,275	2,109,746
Operating Segments | Distribution | Gas sales revenues: | Residential
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,090,702	893,720	1,666,543	1,485,554
Operating Segments | Distribution | Gas sales revenues: | Commercial
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	428,330	326,182	679,091	535,129
Operating Segments | Distribution | Gas sales revenues: | Industrial
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	54,372	31,066	103,053	55,774
Operating Segments | Distribution | Gas sales revenues: | Public authority and other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	26,396	20,227	41,588	33,289
Operating Segments | Distribution | Transportation revenues
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	32,801	30,973	60,670	58,740
Operating Segments | Distribution | Miscellaneous revenues
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	2,680	3,325	5,279	5,721
Operating Segments | Pipeline and Storage
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	166,134	155,443	336,536	325,352
Alternative revenue program revenues	(2,387)	(1,275)	(9,871)	(11,471)
Other revenues	0	0	0	0
Total operating revenues	163,747	154,168	326,665	313,881
Operating Segments | Pipeline and Storage | Gas sales revenues:
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0	0
Operating Segments | Pipeline and Storage | Gas sales revenues: | Residential
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0	0
Operating Segments | Pipeline and Storage | Gas sales revenues: | Commercial
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0	0
Operating Segments | Pipeline and Storage | Gas sales revenues: | Industrial
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0	0
Operating Segments | Pipeline and Storage | Gas sales revenues: | Public authority and other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0	0
Operating Segments | Pipeline and Storage | Transportation revenues
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	163,850	151,565	327,709	316,326
Operating Segments | Pipeline and Storage | Miscellaneous revenues
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 2,284	$ 3,878	$ 8,827	$ 9,026

Revenue and Accounts Receivab_4

Revenue and Accounts Receivable - Allowance for Credit Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Revenue from Contract with Customer [Abstract]
Percent of customers excluded			79.00%
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 64,934	$ 35,089	$ 64,471	$ 29,949
Current period provisions	5,705	11,532	12,075	18,469
Write-offs charged against allowance	(9,029)	(2,381)	(15,458)	(4,669)
Recoveries of amounts previously written off	603	440	1,125	931
Ending balance	$ 62,213	$ 44,680	$ 62,213	$ 44,680

Debt - Schedule of Long-term De

Debt - Schedule of Long-term Debt Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Jan. 14, 2022	Oct. 01, 2021	Sep. 30, 2021
Debt Instrument [Line Items]
Long-term debt	$ 7,960,000			$ 7,360,000
Finance lease obligations	52,537			18,739
Total long-term debt	8,012,537			7,378,739
Less:
Original issue discount on unsecured senior notes and debentures	3,814			2,811
Debt issuance cost	49,724			45,271
Current maturities	2,201,404			2,400,452
Long-term debt, noncurrent	$ 5,757,595			4,930,205
Unsecured 0.625% Senior Notes, due March 2023
Debt Instrument [Line Items]
Interest rate	0.625%
Long-term debt	$ 1,100,000			1,100,000
Unsecured 3.00% Senior Notes, due 2027
Debt Instrument [Line Items]
Interest rate	3.00%
Long-term debt	$ 500,000			500,000
Unsecured 2.625% Senior Notes, due 2029
Debt Instrument [Line Items]
Interest rate	2.625%	2.625%
Long-term debt	$ 500,000			300,000
Unsecured 1.50% Senior Notes, due 2031
Debt Instrument [Line Items]
Interest rate	1.50%		2.85%
Long-term debt	$ 600,000			600,000
Unsecured 5.95% Senior Notes, due 2034
Debt Instrument [Line Items]
Interest rate	5.95%
Long-term debt	$ 200,000			200,000
Unsecured 5.50% Senior Notes, due 2041
Debt Instrument [Line Items]
Interest rate	5.50%
Long-term debt	$ 400,000			400,000
Unsecured 4.15% Senior Notes, due 2043
Debt Instrument [Line Items]
Interest rate	4.15%
Long-term debt	$ 500,000			500,000
Unsecured 4.125% Senior Notes, due 2044
Debt Instrument [Line Items]
Interest rate	4.125%
Long-term debt	$ 750,000			750,000
Unsecured 4.30% Senior Notes, due 2048
Debt Instrument [Line Items]
Interest rate	4.30%
Long-term debt	$ 600,000			600,000
Unsecured 4.125% Senior Notes, due 2049
Debt Instrument [Line Items]
Interest rate	4.125%
Long-term debt	$ 450,000			450,000
Unsecured 3.375% Senior Notes, due 2049
Debt Instrument [Line Items]
Interest rate	3.375%
Long-term debt	$ 500,000			500,000
Unsecured 2.85% Senior Notes, due 2052
Debt Instrument [Line Items]
Interest rate	2.85%
Long-term debt	$ 600,000			0
Floating-rate term loan, due April 2022
Debt Instrument [Line Items]
Long-term debt	0	$ 200,000		200,000
Floating-rate Senior Notes, due March 2023
Debt Instrument [Line Items]
Long-term debt	$ 1,100,000			1,100,000
Medium-term note Series A, 1995-1, 6.67%, due 2025
Debt Instrument [Line Items]
Interest rate	6.67%
Long-term debt	$ 10,000			10,000
Unsecured 6.75% Debentures, due 2028
Debt Instrument [Line Items]
Interest rate	6.75%
Long-term debt	$ 150,000			$ 150,000

Debt - Narrative (Details)

Debt - Narrative (Details)	Mar. 31, 2022USD ($)credit_facility	Jan. 14, 2022USD ($)	Oct. 01, 2021USD ($)	Apr. 01, 2021USD ($)	Mar. 31, 2021	Mar. 30, 2021USD ($)	Mar. 31, 2022USD ($)credit_facility	Mar. 31, 2021USD ($)	Sep. 30, 2021USD ($)
Line Of Credit Facility [Line Items]
Proceeds from issuance of long-term debt							$ 798,802,000	$ 2,797,346,000
Maximum debt-to-total-capitalization ratio							70.00%
Debt-to-total-capitalization ratio	0.48						0.48
Minimum
Line Of Credit Facility [Line Items]
Equity-to-total-capitalization ratio							50.00%
Outstanding indebtedness	$ 15,000,000						$ 15,000,000
Maximum
Line Of Credit Facility [Line Items]
Equity-to-total-capitalization ratio							60.00%
Outstanding indebtedness	100,000,000						$ 100,000,000
Revolving Credit Facility
Line Of Credit Facility [Line Items]
Maximum borrowing capacity	$ 2,500,000,000						$ 2,500,000,000
Number of credit facilities | credit_facility	4						4
Unsecured 1.50% Senior Notes, due 2031
Line Of Credit Facility [Line Items]
Debt instrument, face amount			$ 600,000,000
Interest rate	1.50%		2.85%				1.50%
Effective Interest Rate			2.58%
Proceeds from issuance of long-term debt			$ 589,800,000
Unsecured 2.625% Senior Notes, due 2029
Line Of Credit Facility [Line Items]
Debt instrument, face amount		$ 200,000,000
Interest rate	2.625%	2.625%					2.625%
Effective Interest Rate		2.54%
Floating-rate term loan, due April 2022
Line Of Credit Facility [Line Items]
Repayments of debt		$ 200,800,000
Five Year Unsecured Revolving Credit Agreement
Line Of Credit Facility [Line Items]
Outstanding commercial paper	$ 0						$ 0		$ 0
Five Year Unsecured Revolving Credit Agreement | Commercial Paper
Line Of Credit Facility [Line Items]
Maximum borrowing capacity	1,500,000,000					$ 1,500,000,000	1,500,000,000
Debt agreement term						5 years
Accordion feature	250,000,000						250,000,000
Maximum borrowing capacity post accordion feature	1,750,000,000						1,750,000,000
$900 Million Revolving Credit Facility | Revolving Credit Facility
Line Of Credit Facility [Line Items]
Maximum borrowing capacity	900,000,000						900,000,000
Debt agreement term					3 years
Accordion feature	100,000,000						100,000,000
Maximum borrowing capacity post accordion feature	1,000,000,000						1,000,000,000
Outstanding borrowings	0						0
$50 Million Bank Loan Agreement | Line of Credit
Line Of Credit Facility [Line Items]
Maximum borrowing capacity				$ 50,000,000
Debt agreement term				364 days
Outstanding borrowings	0						0
$50 Million Revolving Credit Facility
Line Of Credit Facility [Line Items]
Outstanding borrowings	0						0
$50 Million Revolving Credit Facility | Revolving Credit Facility
Line Of Credit Facility [Line Items]
Maximum borrowing capacity	$ 50,000,000						50,000,000
Debt agreement term	364 days
Remaining borrowing capacity	$ 44,400,000						$ 44,400,000
Base Rate | Five Year Unsecured Revolving Credit Agreement | Minimum
Line Of Credit Facility [Line Items]
Interest rate spread					0.00%
Base Rate | Five Year Unsecured Revolving Credit Agreement | Maximum
Line Of Credit Facility [Line Items]
Interest rate spread					0.25%
Base Rate | $900 Million Revolving Credit Facility | Revolving Credit Facility | Minimum
Line Of Credit Facility [Line Items]
Interest rate spread					0.00%
Base Rate | $900 Million Revolving Credit Facility | Revolving Credit Facility | Maximum
Line Of Credit Facility [Line Items]
Interest rate spread					0.25%
SOFR | Five Year Unsecured Revolving Credit Agreement | Minimum
Line Of Credit Facility [Line Items]
Interest rate spread					0.75%
SOFR | Five Year Unsecured Revolving Credit Agreement | Maximum
Line Of Credit Facility [Line Items]
Interest rate spread					1.25%
SOFR | $900 Million Revolving Credit Facility | Revolving Credit Facility | Minimum
Line Of Credit Facility [Line Items]
Interest rate spread					0.75%
SOFR | $900 Million Revolving Credit Facility | Revolving Credit Facility | Maximum
Line Of Credit Facility [Line Items]
Interest rate spread					1.25%

Shareholders' Equity - Narrativ

Shareholders' Equity - Narrative (Details) - USD ($)	6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 23, 2022	Jun. 29, 2021
Class of Stock [Line Items]
Net proceeds available	$ 451,300,000
Net proceeds from equity issuances	594,320,000	$ 460,678,000
Shelf Registration Statement
Class of Stock [Line Items]
Debt and equity securities authorized for issuance				$ 5,000,000,000
Debt and equity securities authorized for issuance value remaining	2,200,000,000
At-The-Market
Class of Stock [Line Items]
Equity available for issuance	$ 1,000,000,000		$ 1,000,000,000
Forward sales equity agreement (in shares)	7,381,043
Net proceeds available	$ 759,800,000
Stock issued during period, new issues (in shares)	6,162,269
Net proceeds from equity issuances	$ 594,300,000

Shareholders' Equity - Componen

Shareholders' Equity - Components of Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2022	Mar. 31, 2021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock outstanding, beginning balance (in shares)		132,419,754			132,419,754
Shareholders' equity, beginning balance	$ 8,289,545	$ 7,906,889	$ 7,213,156	$ 6,791,203	$ 7,906,889	$ 6,791,203
Net income	324,999	249,209	296,754	217,678	574,208	514,432
Other comprehensive income (loss)	121,723	(45,947)	137,939	60,121	$ 75,776	198,060
Cash dividends	(93,533)	(90,411)	(80,325)	(79,023)
Public and other stock offerings	336,469	265,861	248,960	220,009
Stock-based compensation plans	$ 4,028	3,944	4,441	3,168
Common stock outstanding, ending balance (in shares)	139,012,029				139,012,029
Shareholders' equity, ending balance	$ 8,983,231	$ 8,289,545	$ 7,820,925	$ 7,213,156	$ 8,983,231	$ 7,820,925
Cash dividends per share (USD per share)	$ 0.68	$ 0.68	$ 0.625	$ 0.625	$ 1.36	$ 1.25
Common stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock outstanding, beginning balance (in shares)	135,425,081	132,419,754	128,152,961	125,882,477	132,419,754	125,882,477
Shareholders' equity, beginning balance	$ 677	$ 662	$ 641	$ 629	$ 662	$ 629
Public and other stock offerings (in shares)	3,509,116	2,730,115	2,498,026	2,126,118
Public and other stock offerings	$ 18	$ 13	$ 12	$ 11
Stock-based compensation plans (in shares)	77,832	275,212	16,122	144,366
Stock-based compensation plans	$ 0	$ 2	$ 0	$ 1
Common stock outstanding, ending balance (in shares)	139,012,029	135,425,081	130,667,109	128,152,961	139,012,029	130,667,109
Shareholders' equity, ending balance	$ 695	$ 677	$ 653	$ 641	$ 695	$ 653
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shareholders' equity, beginning balance	5,293,541	5,023,751	4,600,314	4,377,149	5,023,751	4,377,149
Public and other stock offerings	336,451	265,848	248,948	219,998
Stock-based compensation plans	4,028	3,942	4,441	3,167
Shareholders' equity, ending balance	5,634,020	5,293,541	4,853,703	4,600,314	5,634,020	4,853,703
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shareholders' equity, beginning balance	23,856	69,803	2,532	(57,589)	69,803	(57,589)
Other comprehensive income (loss)	121,723	(45,947)	137,939	60,121
Shareholders' equity, ending balance	145,579	23,856	140,471	2,532	145,579	140,471
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shareholders' equity, beginning balance	2,971,471	2,812,673	2,609,669	2,471,014	2,812,673	2,471,014
Net income	324,999	249,209	296,754	217,678
Cash dividends	(93,533)	(90,411)	(80,325)	(79,023)
Shareholders' equity, ending balance	$ 3,202,937	$ 2,971,471	$ 2,826,098	$ 2,609,669	$ 3,202,937	$ 2,826,098

Shareholders' Equity - Forward

Shareholders' Equity - Forward Sales Agreement (Details) $ / shares in Units, $ in Thousands	6 Months Ended
	Mar. 31, 2022USD ($)$ / sharesshares
Forward Contract Indexed to Issuer's Equity [Line Items]
Net proceeds available	$ 451,300
Forward Sales Equity Agreement Maturing Quarter Ended September 29, 2023
Forward Contract Indexed to Issuer's Equity [Line Items]
Shares available (in shares) | shares	4,290,498
Net proceeds available	$ 451,292
Forward price (USD per share) | $ / shares	$ 105.18

Shareholders' Equity - Schedule

Shareholders' Equity - Schedule of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2022	Mar. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Shareholders' equity, beginning balance	$ 8,289,545	$ 7,906,889	$ 7,213,156	$ 6,791,203	$ 7,906,889	$ 6,791,203
Other comprehensive income (loss) before reclassifications					74,288	195,777
Amounts reclassified from accumulated other comprehensive income					1,488	2,283
Net current-period other comprehensive income (loss)	121,723	(45,947)	137,939	60,121	75,776	198,060
Shareholders' equity, ending balance	8,983,231	8,289,545	7,820,925	7,213,156	8,983,231	7,820,925
Available- for-Sale Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Shareholders' equity, beginning balance		47		238	47	238
Other comprehensive income (loss) before reclassifications					(230)	(129)
Amounts reclassified from accumulated other comprehensive income					0	0
Net current-period other comprehensive income (loss)					(230)	(129)
Shareholders' equity, ending balance	(183)		109		(183)	109
Interest Rate Agreement Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Shareholders' equity, beginning balance		69,756		(57,827)	69,756	(57,827)
Other comprehensive income (loss) before reclassifications					74,518	195,906
Amounts reclassified from accumulated other comprehensive income					1,488	2,283
Net current-period other comprehensive income (loss)					76,006	198,189
Shareholders' equity, ending balance	145,762		140,362		145,762	140,362
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Shareholders' equity, beginning balance	23,856	69,803	2,532	(57,589)	69,803	(57,589)
Net current-period other comprehensive income (loss)	121,723	(45,947)	137,939	60,121
Shareholders' equity, ending balance	$ 145,579	$ 23,856	$ 140,471	$ 2,532	$ 145,579	$ 140,471

Winter Storm Uri (Details)

Winter Storm Uri (Details) - USD ($)	1 Months Ended
	Feb. 28, 2021	Mar. 31, 2022	Sep. 30, 2021	Sep. 14, 2021	Jul. 30, 2021	Mar. 31, 2021
Unusual or Infrequent Item, or Both [Line Items]
Aggregate natural gas purchases	$ 2,300,000,000
Regulatory assets		$ 2,475,545,000	$ 2,521,441,000
Winter Storm Uri incremental costs
Unusual or Infrequent Item, or Both [Line Items]
Regulatory assets		2,106,521,000	$ 2,100,728,000
Winter Storm Uri incremental costs | Winter Storm Uri
Unusual or Infrequent Item, or Both [Line Items]
Regulatory assets		2,100,000,000
Winter Storm Uri incremental costs | Kansas | Winter Storm Uri
Unusual or Infrequent Item, or Both [Line Items]
Regulatory assets		87,900,000
Winter Storm Uri incremental costs | Texas | Winter Storm Uri
Unusual or Infrequent Item, or Both [Line Items]
Regulatory assets		$ 2,018,600,000
Extraordinary Gas Cost | Kansas | Winter Storm Uri
Unusual or Infrequent Item, or Both [Line Items]
Regulatory assets				$ 94,100,000
Extraordinary Gas Cost | Texas | Winter Storm Uri
Unusual or Infrequent Item, or Both [Line Items]
Regulatory assets					$ 2,000,000,000
Senior Notes Due 2023
Unusual or Infrequent Item, or Both [Line Items]
Debt instrument, face amount						$ 2,200,000,000
Senior Notes Due 2023 | Texas
Unusual or Infrequent Item, or Both [Line Items]
Debt instrument, face amount						2,200,000,000
Other administrative costs						$ 600,000

Interim Pension and Other Pos_3

Interim Pension and Other Postretirement Benefit Plan Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Contribution to postretirement medical plans			$ 7,800
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4,324	$ 4,613	8,647	$ 9,225
Interest cost	5,064	5,028	10,127	10,056
Expected return on assets	(7,383)	(6,978)	(14,766)	(13,956)
Amortization of prior service cost (credit)	(58)	(58)	(116)	(116)
Amortization of actuarial (gain) loss	1,951	3,171	3,902	6,343
Net periodic pension cost	3,898	5,776	7,794	11,552
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	2,558	4,306	5,117	8,612
Interest cost	2,684	2,660	5,367	5,320
Expected return on assets	(3,313)	(2,614)	(6,625)	(5,228)
Amortization of prior service cost (credit)	(3,308)	43	(6,617)	86
Amortization of actuarial (gain) loss	0	0	0	0
Net periodic pension cost	(1,379)	$ 4,395	(2,758)	$ 8,790
Minimum | Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Expected future contributions	15,000		15,000
Maximum | Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Expected future contributions	$ 25,000		$ 25,000

Commitments and Contingencies (

Commitments and Contingencies (Details)	Feb. 08, 2021USD ($)	Mar. 31, 2022$ / McfBcf	Mar. 31, 2022USD ($)
Long-term Purchase Commitment [Line Items]
Self-insured retention | $			$ 1,000,000
Damages sought, value | $	$ 1,600,000
Supply Commitment
Long-term Purchase Commitment [Line Items]
Contract term			1 year
Long-term purchase commitment, minimum volume required		0.4
Supply Commitment | Short-term Contract with Customer
Long-term Purchase Commitment [Line Items]
Contract term		1 year
Long-term purchase commitment, minimum volume required		24.4
Supply Commitment | Long-term Contract with Customer Within Two To Three Years
Long-term Purchase Commitment [Line Items]
Long-term purchase commitment, minimum volume required		3.5
Supply Commitment | Minimum
Long-term Purchase Commitment [Line Items]
Long-term purchase commitment, amount (USD per MCF) | $ / Mcf		4.11
Supply Commitment | Minimum | Long-term Contract with Customer Within Two To Three Years
Long-term Purchase Commitment [Line Items]
Contract term		2 years
Supply Commitment | Maximum
Long-term Purchase Commitment [Line Items]
Long-term purchase commitment, amount (USD per MCF) | $ / Mcf		12.85
Supply Commitment | Maximum | Long-term Contract with Customer Within Two To Three Years
Long-term Purchase Commitment [Line Items]
Contract term		3 years

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2021
Income Tax Contingency [Line Items]
Effective income tax rate	10.10%	17.20%	8.30%	19.80%
Regulatory liabilities	$ 1,389,519		$ 1,389,519		$ 1,424,195
Winter Storm Uri
Income Tax Contingency [Line Items]
Deferred tax liabilities					471,000
Deferred tax asset, decrease during period	451,100
Domestic Tax Authority
Income Tax Contingency [Line Items]
Operating loss carryforwards	438,000		438,000		850,200
State and Local Jurisdiction
Income Tax Contingency [Line Items]
Operating loss carryforwards	31,100		31,100
Operating loss carryforwards, federal tax effects	8,200		8,200
Tax credit carryforward, amount	1,700		1,700
Tax credit carryforward, federal tax impacts	500		$ 500
Minimum
Income Tax Contingency [Line Items]
Return basis, term			3 years
Maximum
Income Tax Contingency [Line Items]
Return basis, term			5 years
Regulatory excess deferred taxes
Income Tax Contingency [Line Items]
Deferred tax liabilities, net	578,500		$ 578,500
Regulatory liabilities	626,874		626,874		705,084
Regulatory excess deferred taxes | Other Current Liabilities
Income Tax Contingency [Line Items]
Deferred tax liabilities, net	156,000		156,000		$ 155,900
Regulatory excess deferred taxes, to be returned, tranche one
Income Tax Contingency [Line Items]
Deferred tax liabilities, net	458,300		$ 458,300
Regulatory excess deferred taxes, to be returned, tranche one | Minimum
Income Tax Contingency [Line Items]
Return basis, term			35 months
Regulatory excess deferred taxes, to be returned, tranche one | Maximum
Income Tax Contingency [Line Items]
Return basis, term			60 months
Regulatory excess deferred taxes, to be returned, tranche two
Income Tax Contingency [Line Items]
Regulatory liabilities	105,100		$ 105,100
Regulatory excess deferred taxes, to be returned, tranche two | Minimum
Income Tax Contingency [Line Items]
Return basis, term			15 years
Regulatory excess deferred taxes, to be returned, tranche two | Maximum
Income Tax Contingency [Line Items]
Return basis, term			69 years
Regulatory excess deferred taxes, to be returned, tranche three
Income Tax Contingency [Line Items]
Deferred tax liabilities, net	$ 15,100		$ 15,100

Financial Instruments - Narrati

Financial Instruments - Narrative (Details)	3 Months Ended		6 Months Ended
	Mar. 31, 2022USD ($)	Mar. 31, 2021USD ($)	Mar. 31, 2022USD ($)BcfMMcf	Mar. 31, 2021USD ($)	Sep. 30, 2021USD ($)
Derivative [Line Items]
Energy measure | MMcf			4,777
Contract netting	$ 0		$ 0		$ 0
Cash collateral	0		0		$ 0
Net gain (loss) on settled interest rate agreements	(1,000,000)	$ (1,500,000)	(1,900,000)	$ (2,900,000)
Net realized gain (loss) in AOCI	$ (60,200,000)		$ (60,200,000)
Gas Purchases | Not Designated As Hedges: | Commodity contracts
Derivative [Line Items]
Hedging percent	42.00%		42.00%
Energy measure | Bcf			23.9
Minimum | Gas Purchases | Not Designated As Hedges: | Commodity contracts
Derivative [Line Items]
Hedging percent	25.00%		25.00%
Maximum | Gas Purchases | Not Designated As Hedges: | Commodity contracts
Derivative [Line Items]
Hedging percent	50.00%		50.00%

Financial Instruments - Schedul

Financial Instruments - Schedule of Derivative Instruments in Statement of Financial Position, Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Derivatives Fair Value [Line Items]
Net financial instruments, assets	$ 283,529	$ 230,686
Net financial instruments, liabilities	(1,129)	(5,269)
Designated As Hedges:
Derivatives Fair Value [Line Items]
Gross financial instruments, assets	265,524	169,469
Gross financial instruments, liabilities	0	0
Designated As Hedges: | Other current assets | Interest rate contracts
Derivatives Fair Value [Line Items]
Gross financial instruments, assets	109,887
Designated As Hedges: | Other current liabilities | Interest rate contracts
Derivatives Fair Value [Line Items]
Gross financial instruments, liabilities	0
Designated As Hedges: | Deferred charges and other assets | Interest rate contracts
Derivatives Fair Value [Line Items]
Gross financial instruments, assets	155,637	169,469
Designated As Hedges: | Deferred credits and other liabilities | Interest rate contracts
Derivatives Fair Value [Line Items]
Gross financial instruments, liabilities	0	0
Not Designated As Hedges:
Derivatives Fair Value [Line Items]
Gross financial instruments, assets	18,005	61,217
Gross financial instruments, liabilities	(1,129)	(5,269)
Not Designated As Hedges: | Other current assets | Commodity contracts
Derivatives Fair Value [Line Items]
Gross financial instruments, assets	18,005	55,073
Not Designated As Hedges: | Other current liabilities | Commodity contracts
Derivatives Fair Value [Line Items]
Gross financial instruments, liabilities	(1,113)	(5,269)
Not Designated As Hedges: | Deferred charges and other assets | Commodity contracts
Derivatives Fair Value [Line Items]
Gross financial instruments, assets	0	6,144
Not Designated As Hedges: | Deferred credits and other liabilities | Commodity contracts
Derivatives Fair Value [Line Items]
Gross financial instruments, liabilities	$ (16)	$ 0

Financial Instruments - Sched_2

Financial Instruments - Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Increase in fair value:
Interest rate agreements	$ 121,140	$ 136,864	$ 74,518	$ 195,906
Recognition of losses in earnings due to settlements:
Interest rate agreements	744	1,141	1,488	2,283
Total other comprehensive income from hedging, net of tax	$ 121,884	$ 138,005	$ 76,006	$ 198,189

Financial Instruments - Sched_3

Financial Instruments - Schedule Of Expected Deferred Gains (Losses) Recognition (Details) $ in Thousands	6 Months Ended
	Mar. 31, 2022USD ($)
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Next twelve months	$ (2,976)
Thereafter	(57,250)
Total	$ (60,226)

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial instruments net assets	$ 283,529	$ 230,686
Debt and equity securities	101,819	108,071
Total assets	385,348	338,757
Financial instruments net liability	1,129	5,269
Registered investment companies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	29,729	35,175
Bond mutual funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	33,209	34,298
Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt securities	34,271	35,655
Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	4,610	2,943
Quoted Prices in Active Markets (Level 1)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial instruments gross assets	0	0
Debt and equity securities	62,938	69,473
Total assets	62,938	69,473
Financial instruments gross liability	0	0
Quoted Prices in Active Markets (Level 1) | Registered investment companies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	29,729	35,175
Quoted Prices in Active Markets (Level 1) | Bond mutual funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	33,209	34,298
Quoted Prices in Active Markets (Level 1) | Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt securities	0	0
Quoted Prices in Active Markets (Level 1) | Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0	0
Significant Other Observable Inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial instruments gross assets	283,529	230,686
Debt and equity securities	38,881	38,598
Total assets	322,410	269,284
Financial instruments gross liability	1,129	5,269
Significant Other Observable Inputs (Level 2) | Registered investment companies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0	0
Significant Other Observable Inputs (Level 2) | Bond mutual funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0	0
Significant Other Observable Inputs (Level 2) | Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt securities	34,271	35,655
Significant Other Observable Inputs (Level 2) | Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	4,610	2,943
Significant Other Unobservable Inputs (Level 3)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial instruments gross assets	0	0
Debt and equity securities	0	0
Total assets	0	0
Financial instruments gross liability	0	0
Significant Other Unobservable Inputs (Level 3) | Registered investment companies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0	0
Significant Other Unobservable Inputs (Level 3) | Bond mutual funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0	0
Significant Other Unobservable Inputs (Level 3) | Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt securities	0	0
Significant Other Unobservable Inputs (Level 3) | Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	$ 0	$ 0

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - USD ($)	Mar. 31, 2022	Sep. 30, 2021
Schedule of Available For Sale Securities [Abstract]
Allowance for credit losses	$ 0
Cost basis	$ 34,500,000	$ 35,600,000

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Debt Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Carrying Amount	$ 7,960,000	$ 7,360,000
Fair Value	$ 7,949,543	$ 8,086,136