Atmos Energy (ATO) 10-Q 7 Aug 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Jun. 30, 2019	Jul. 31, 2019
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2019
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)		118,200,689
Entity Central Index Key	0000731802
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Amendment Flag	false
Virginia
Entity Information [Line Items]
Entity Incorporation, State or Country Code	VA

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($)	Jun. 30, 2019	Sep. 30, 2018
ASSETS
Property, plant and equipment	$ 13,687,833,000	$ 12,567,373,000
Less accumulated depreciation and amortization	2,347,237,000	2,196,226,000
Net property, plant and equipment	11,340,596,000	10,371,147,000
Current assets
Cash and cash equivalents	46,163,000	13,771,000
Accounts receivable, net	285,433,000	253,295,000
Gas stored underground	106,014,000	165,732,000
Other current assets	65,924,000	46,055,000
Total current assets	503,534,000	478,853,000
Goodwill	730,419,000	730,419,000
Deferred charges and other assets	306,549,000	294,018,000
Total assets	12,881,098,000	11,874,437,000
Shareholders’ equity
Common stock, no par value (stated at $0.005 per share)	591,000	556,000
Additional paid-in capital	3,599,724,000	2,974,926,000
Accumulated other comprehensive loss	(115,663,000)	(83,647,000)
Retained earnings	2,157,344,000	1,878,116,000
Shareholders’ equity	5,641,996,000	4,769,951,000
Long-term debt	3,529,135,000	2,493,665,000
Total capitalization	9,171,131,000	7,263,616,000
Current liabilities
Accounts payable and accrued liabilities	206,500,000	217,283,000
Other current liabilities	494,932,000	547,068,000
Short-term debt	74,942,000	575,780,000
Current maturities of long-term debt	125,000,000	575,000,000
Total current liabilities	901,374,000	1,915,131,000
Deferred income taxes	1,280,307,000	1,154,067,000
Regulatory excess deferred taxes (See Note 13)	709,974,000	739,670,000
Regulatory Cost of Removal Liability, Noncurrent	464,855,000	466,405,000
Pension and postretirement liabilities	177,602,000	177,520,000
Deferred credits and other liabilities	175,855,000	158,028,000
Total shareholders' equity and liabilities	$ 12,881,098,000	$ 11,874,437,000

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (PARENTHETICAL) - $ / shares	Jun. 30, 2019	Sep. 30, 2018
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)	118,196,113	111,273,683
Common stock outstanding (in shares)	118,196,113	111,273,683

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating revenues
Total operating revenues	$ 485,738	$ 562,245	$ 2,458,165	$ 2,670,846
Cost of Revenue	31,326	130,886	845,167	1,124,763
Operation and maintenance expense	164,545	143,748	452,572	431,952
Depreciation and amortization expense	97,700	90,671	290,537	268,426
Taxes, other than income	69,965	72,620	213,546	208,400
Operating income	122,202	124,320	656,343	637,305
Other non-operating income (expense)	1,645	(3,330)	(1,846)	(8,054)
Interest charges	19,592	23,349	74,390	82,162
Income before income taxes	104,255	97,641	580,107	547,089
Income tax expense	23,789	26,448	127,107	(17,228)
Net income	$ 80,466	$ 71,193	$ 453,000	$ 564,317
Basic net income per share	$ 0.68	$ 0.64	$ 3.89	$ 5.09
Diluted net income per share	0.68	0.64	3.88	5.09
Cash dividends per share	$ 0.525	$ 0.485	$ 1.575	$ 1.455
Basic weighted average shares outstanding	118,075	111,851	116,485	110,707
Diluted weighted average shares outstanding	118,430	111,851	116,673	110,707
Other comprehensive income (loss), net of tax
Net unrealized holding gains (losses) on available-for-sale securities, net of tax	$ 94	$ 310	$ 191	$ (736)
Cash flow hedges:
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	1,053	8,320	(23,997)	29,609
Total other comprehensive income (loss)	1,147	8,630	(23,806)	28,873
Total comprehensive income	81,613	79,823	429,194	593,190
Operating Segments | Distribution segment
Operating revenues
Total operating revenues	444,944	535,488	2,341,668	2,595,571
Operation and maintenance expense	123,998	110,568	347,386	343,860
Depreciation and amortization expense	70,611	66,504	210,224	197,587
Taxes, other than income	62,134	64,420	189,377	184,219
Operating income	48,683	63,109	447,083	448,207
Other non-operating income (expense)	3,005	(2,518)	1,791	(5,961)
Interest charges	10,597	13,315	44,703	51,581
Income before income taxes	41,091	47,276	404,171	390,665
Income tax expense	8,693	11,932	85,195	(39,021)
Net income	32,398	35,344	318,976	429,686
Operating Segments | Pipeline and storage segment
Operating revenues
Total operating revenues	149,198	127,633	419,318	375,051
Operation and maintenance expense	40,855	33,494	106,120	89,027
Depreciation and amortization expense	27,089	24,167	80,313	70,839
Taxes, other than income	7,831	8,200	24,169	24,181
Operating income	73,519	61,211	209,260	189,098
Other non-operating income (expense)	(1,360)	(812)	(3,637)	(2,093)
Interest charges	8,995	10,034	29,687	30,581
Income before income taxes	63,164	50,365	175,936	156,424
Income tax expense	15,096	14,516	41,912	21,793
Net income	48,068	35,849	134,024	134,631
Intersegment eliminations
Operating revenues
Total operating revenues	(108,404)	(100,876)	(302,821)	(299,776)
Operation and maintenance expense	(308)	(314)	(934)	(935)
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 (expense)	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
Natural Gas, US Regulated
Operating revenues
Cost of Revenue	31,326	130,886	845,167	1,124,763
Natural Gas, US Regulated | Operating Segments | Distribution segment
Operating revenues
Cost of Revenue	139,518	230,887	1,147,598	1,421,698
Natural Gas, US Regulated | Operating Segments | Pipeline and storage segment
Operating revenues
Cost of Revenue	(96)	561	(544)	1,906
Natural Gas, US Regulated | Intersegment eliminations
Operating revenues
Cost of Revenue	$ (108,096)	$ (100,562)	$ (301,887)	$ (298,841)

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (PARENTHETICAL) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Net unrealized holding gains (losses) on available-for-sale securities, tax	$ 27	$ 92	$ 56	$ (246)
Amortization and unrealized gain (loss) of interest rate agreements, tax	$ 312	$ 2,460	$ (7,093)	$ 8,486

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash Flows From Operating Activities
Net income	$ 453,000	$ 564,317
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	290,537	268,426
Deferred income taxes	120,220	139,852
One-time income tax benefit	0	(165,522)
Other	9,649	18,007
Net assets / liabilities from risk management activities	(1,976)	912
Net change in operating assets and liabilities	(62,502)	209,304
Net cash provided by operating activities	808,928	1,035,296
Cash Flows From Investing Activities
Capital expenditures	(1,199,199)	(1,088,472)
Proceeds from the sale of discontinued operations	4,000	3,000
Debt and equity securities activities, net	(4,041)	(7,857)
Other, net	3,839	6,105
Net cash used in investing activities	(1,195,401)	(1,087,224)
Cash Flows From Financing Activities
Net decrease in short-term debt	(500,838)	(202,968)
Net proceeds from equity offering	593,731	395,092
Issuance of common stock through stock purchase and employee retirement plans	14,128	15,850
Proceeds from issuance of long-term debt	1,045,221	0
Settlements of interest rate swap	90,141	0
Repayments of Long-term Debt	450,000	0
Cash dividends paid	(181,982)	(160,007)
Debt issuance costs	(11,254)	0
Other	0	(1,518)
Net cash provided by financing activities	418,865	46,449
Net increase (decrease) in cash and cash equivalents	32,392	(5,479)
Cash and cash equivalents at beginning of period	13,771	26,409
Cash and cash equivalents at end of period	$ 46,163	$ 20,930

Nature of Business

Nature of Business	9 Months Ended
	Jun. 30, 2019
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 June 30, 2019 , 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	9 Months Ended
	Jun. 30, 2019
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, aside from accounting policy changes noted below, 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, 2018 . 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, 2018 . Because of seasonal and other factors, the results of operations for the nine -month period ended June 30, 2019 are not indicative of our results of operations for the full 2019 fiscal year, which ends September 30, 2019 . No events have occurred subsequent to the balance sheet date that would require recognition or disclosure in the 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, 2018 . During the second quarter of fiscal 2019, we completed our annual goodwill impairment assessment. Based on the assessment performed, we determined that our goodwill was not impaired. Accounting pronouncements adopted in fiscal 2019 During the first quarter of fiscal 2019, we adopted the following accounting guidance updates, effective October 1, 2018. The adoption of this new guidance, individually and collectively, did not have a material impact on our financial position, results of operations or cash flows. • Revenue recognition - Under the new guidance, we are required to recognize revenue when we transfer promised goods or services to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those goods or services. See Note 5 for our discussion of the effects of implementing this standard. • Classification and measurement of financial instruments - The new guidance requires that we recognize changes in the fair value of our equity securities formerly designated as available-for-sale in other non-operating income (expense) in our condensed consolidated statement of comprehensive income on a prospective basis from the date of adoption. However, we continue to classify cash flows from purchases and sales of equity securities within investing activities given the nature of these securities. Additionally, in accordance with the guidance, we reclassified a net $8.2 million unrealized gain related to these equity securities from accumulated other comprehensive income (AOCI) to retained earnings. The accounting for debt securities designated as available-for-sale did not change as a result of this new guidance. Accordingly, changes in the fair value of these securities will continue to be recorded as a component of AOCI. • Presentation of the Components of Net Periodic Benefit Cost - The new guidance requires us to present only the current service cost component of the net benefit cost within operations and maintenance expense in the statement of comprehensive income. The remaining components of net benefit cost are now recorded in other non-operating income (expense) in our condensed consolidated statements of comprehensive income. The change in presentation of these costs was implemented on a retrospective basis as required by the guidance. In lieu of determining how each component of the net periodic benefit cost was actually reflected in the prior periods’ condensed statement of comprehensive income, we elected to utilize a practical expedient that permits the use of the amounts disclosed for these costs in our pension and post-retirement benefit plans footnote as the basis to retroactively apply this standard. In addition, under the new guidance, only the service cost component of net benefit cost is eligible for capitalization (e.g., as part of inventory or property, plant, and equipment). We continue to capitalize these costs into property, plant and equipment. However, the Federal Energy Regulatory Commission (FERC), which establishes the regulatory accounting practices for rate-regulated entities, issued guidance that permits such entities the option to continue to capitalize non-service benefit costs for regulatory purposes. Since the accounting guidelines by the FERC are typically followed by our state regulatory authorities, for U.S. GAAP reporting purposes, we are prospectively deferring into a regulatory asset the portion of non-service components of net periodic benefit cost that are capitalizable for regulatory purposes. • Accounting for Implementation Costs Incurred in A Hosting Arrangement That Is A Service Contract - The new guidance aligns the requirements for capitalizing implementation costs incurred for these contracts with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). We elected to early adopt the new guidance on a prospective basis. Accordingly, we will capitalize the up-front costs incurred for cloud computing arrangements had they been capitalizable in a similar on-premise software solution. Accounting pronouncements that will be effective after fiscal 2019 In February 2016, the Financial Accounting Standards Board (FASB) issued a comprehensive new leasing standard that will require lessees to recognize a lease liability and a right-of-use asset for all leases, including operating leases, with a term greater than 12 months on its balance sheet. Subsequently, the FASB issued practical expedients to 1) allow entities to not evaluate existing or expired land easements that were not previously accounted for as leases under the current guidance and 2) allow entities the option to adopt the standard and recognize a cumulative–effect adjustment to the opening balance of retained earnings in the period of adoption rather than applying the new guidance at the beginning of the earliest comparative period presented in the year of adoption. The new standard will be effective for us beginning on October 1, 2019. The impact of this change on our financial position is not reasonably estimable at this time. We do not anticipate the adoption of this standard will have a material impact to our results of operations or cash flows. We continue to evaluate our adoption of certain practical expedients, however we currently anticipate adopting the following practical expedients: • land easements under the provisions of ASU 2018-01, as described above, • package of three practical expedients described in ASC 842-10-65-1 and • transition method practical expedient provided in ASU 2018-11, as described above. We are implementing a new lease accounting system, which we will utilize to capture, track and account for lease data. The new system will also aid in automating the compilation of disclosure information. In June 2016, the FASB issued new guidance which will require credit losses on most financial assets measured at amortized cost and certain other instruments to be measured using an expected credit loss model. Under this model, entities will estimate credit losses over the entire contractual term of the instrument from the date of initial recognition of that instrument. In contrast, current U.S. GAAP is based on an incurred loss model that delays recognition of credit losses until it is probable the loss has been incurred. The new guidance also introduces a new impairment recognition model for available-for-sale debt securities that will require credit losses for available-for-sale debt securities to be recorded through an allowance account. The new standard will be effective for us beginning on October 1, 2020; early adoption is permitted. We are currently evaluating the potential impact of this new guidance on our financial position, results of operations and cash flows. In August 2018, the FASB issued new guidance that modifies the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. The guidance removes the disclosure requirements for the amounts of gain/loss and prior service cost/credit amortization expected in the following year and the disclosure of the effect of a one-percentage-point change in the health care cost trend rate, among other changes. The guidance adds certain disclosures including the weighted average interest crediting rate for cash balance plans and a narrative description for the significant change in gains and losses as well as any other significant change in the plan obligations or assets. The new guidance is effective for us in the fiscal year beginning October 1, 2020 and should be applied on a retrospective basis to all periods presented. Early adoption is permitted. The adoption of this new guidance impacts only our disclosures. We intend to early adopt the guidance as of September 30, 2019. 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 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 and our regulatory excess deferred taxes and regulatory cost of removal obligation are reported separately. Significant regulatory assets and liabilities as of June 30, 2019 and September 30, 2018 included the following: June 30, September 30, (In thousands) Regulatory assets: Pension and postretirement benefit costs $ 8,007 $ 6,496 Infrastructure mechanisms (1) 111,211 96,739 Deferred gas costs 7,227 1,927 Recoverable loss on reacquired debt 7,000 8,702 Deferred pipeline record collection costs 25,347 20,467 Rate case costs 1,413 2,741 Other 4,465 6,739 $ 164,670 $ 143,811 Regulatory liabilities: Regulatory excess deferred taxes (2) $ 731,837 $ 744,895 Regulatory cost of service reserve (3) 6,079 22,508 Regulatory cost of removal obligation 526,403 522,175 Deferred gas costs 66,171 94,705 Asset retirement obligation 12,887 12,887 APT annual adjustment mechanism 63,130 35,228 Pension and postretirement benefit costs 80,330 69,113 Other 3,038 9,486 $ 1,489,875 $ 1,510,997 (1) Infrastructure mechanisms in Texas and Louisiana 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) The TCJA resulted in the remeasurement of the net deferred tax liability included in our rate base. Of this amount, $21.9 million as of June 30, 2019 and $5.2 million as of September 30, 2018 is recorded in other current liabilities. The period and timing of the return of the excess deferred taxes is being determined by regulators in each of our jurisdictions. See Note 13 for further information. (3) Effective January 1, 2018, regulators in each of our service areas required us to establish a regulatory liability for the difference in recoverable federal taxes included in revenues based on the former 35% federal statutory rate and the new 21% federal statutory rate for service provided on or after January 1, 2018. The period and timing of the return of this liability to utility customers is being determined by regulators in each of our jurisdictions. See Note 13

Segment Information

Segment Information	9 Months Ended
	Jun. 30, 2019
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, 2018 . Income statements and capital expenditures for the three and nine months ended June 30, 2019 and 2018 by segment are presented in the following tables: Three Months Ended June 30, 2019 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 444,287 $ 41,451 $ — $ 485,738 Intersegment revenues 657 107,747 (108,404 ) — Total operating revenues 444,944 149,198 (108,404 ) 485,738 Purchased gas cost 139,518 (96 ) (108,096 ) 31,326 Operation and maintenance expense 123,998 40,855 (308 ) 164,545 Depreciation and amortization expense 70,611 27,089 — 97,700 Taxes, other than income 62,134 7,831 — 69,965 Operating income 48,683 73,519 — 122,202 Other non-operating income (expense) 3,005 (1,360 ) — 1,645 Interest charges 10,597 8,995 — 19,592 Income before income taxes 41,091 63,164 — 104,255 Income tax expense 8,693 15,096 — 23,789 Net income $ 32,398 $ 48,068 $ — $ 80,466 Capital expenditures $ 316,825 $ 104,788 $ — $ 421,613 Three Months Ended June 30, 2018 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 534,816 $ 27,429 $ — $ 562,245 Intersegment revenues 672 100,204 (100,876 ) — Total operating revenues 535,488 127,633 (100,876 ) 562,245 Purchased gas cost 230,887 561 (100,562 ) 130,886 Operation and maintenance expense 110,568 33,494 (314 ) 143,748 Depreciation and amortization expense 66,504 24,167 — 90,671 Taxes, other than income 64,420 8,200 — 72,620 Operating income 63,109 61,211 — 124,320 Other non-operating expense (2,518 ) (812 ) — (3,330 ) Interest charges 13,315 10,034 — 23,349 Income before income taxes 47,276 50,365 — 97,641 Income tax expense 11,932 14,516 — 26,448 Net income $ 35,344 $ 35,849 $ — $ 71,193 Capital expenditures $ 284,209 $ 110,285 $ — $ 394,494 Nine Months Ended June 30, 2019 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 2,339,660 $ 118,505 $ — $ 2,458,165 Intersegment revenues 2,008 300,813 (302,821 ) — Total operating revenues 2,341,668 419,318 (302,821 ) 2,458,165 Purchased gas cost 1,147,598 (544 ) (301,887 ) 845,167 Operation and maintenance expense 347,386 106,120 (934 ) 452,572 Depreciation and amortization expense 210,224 80,313 — 290,537 Taxes, other than income 189,377 24,169 — 213,546 Operating income 447,083 209,260 — 656,343 Other non-operating income (expense) 1,791 (3,637 ) — (1,846 ) Interest charges 44,703 29,687 — 74,390 Income before income taxes 404,171 175,936 — 580,107 Income tax expense 85,195 41,912 — 127,107 Net income $ 318,976 $ 134,024 $ — $ 453,000 Capital expenditures $ 912,640 $ 286,559 $ — $ 1,199,199 Nine Months Ended June 30, 2018 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 2,593,578 $ 77,268 $ — $ 2,670,846 Intersegment revenues 1,993 297,783 (299,776 ) — Total operating revenues 2,595,571 375,051 (299,776 ) 2,670,846 Purchased gas cost 1,421,698 1,906 (298,841 ) 1,124,763 Operation and maintenance expense 343,860 89,027 (935 ) 431,952 Depreciation and amortization expense 197,587 70,839 — 268,426 Taxes, other than income 184,219 24,181 — 208,400 Operating income 448,207 189,098 — 637,305 Other non-operating expense (5,961 ) (2,093 ) — (8,054 ) Interest charges 51,581 30,581 — 82,162 Income before income taxes 390,665 156,424 — 547,089 Income tax (benefit) expense (39,021 ) 21,793 — (17,228 ) Net income $ 429,686 $ 134,631 $ — $ 564,317 Capital expenditures $ 749,693 $ 338,779 $ — $ 1,088,472 Balance sheet information at June 30, 2019 and September 30, 2018 by segment is presented in the following tables: June 30, 2019 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Property, plant and equipment, net $ 8,404,238 $ 2,936,358 $ — $ 11,340,596 Total assets $ 12,083,315 $ 3,174,516 $ (2,376,733 ) $ 12,881,098 September 30, 2018 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Property, plant and equipment, net $ 7,644,693 $ 2,726,454 $ — $ 10,371,147 Total assets $ 11,109,128 $ 2,963,480 $ (2,198,171 ) $ 11,874,437

Earnings Per Share

Earnings Per Share	9 Months Ended
	Jun. 30, 2019
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 , when the impact is dilutive. Basic and diluted earnings per share for the three and nine months ended June 30, 2019 and 2018 are calculated as follows: Three Months Ended June 30 Nine Months Ended June 30 2019 2018 2019 2018 (In thousands, except per share amounts) Basic Earnings Per Share Net income $ 80,466 $ 71,193 $ 453,000 $ 564,317 Less: Income allocated to participating securities 64 59 386 545 Income available to common shareholders $ 80,402 $ 71,134 $ 452,614 $ 563,772 Basic weighted average shares outstanding 118,075 111,851 116,485 110,707 Net income per share — Basic $ 0.68 $ 0.64 $ 3.89 $ 5.09 Diluted Earnings Per Share Income available to common shareholders $ 80,402 $ 71,134 $ 452,614 $ 563,772 Effect of dilutive shares — — — — Income available to common shareholders $ 80,402 $ 71,134 $ 452,614 $ 563,772 Basic weighted average shares outstanding 118,075 111,851 116,485 110,707 Dilutive shares 355 — 188 — Diluted weighted average shares outstanding 118,430 111,851 116,673 110,707 Net income per share - Diluted $ 0.68 $ 0.64 $ 3.88 $ 5.09

Revenue

Revenue	9 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer	Revenue Effective October 1, 2018, we adopted the new guidance under Accounting Standards Codification (ASC) Topic 606. The implementation of the new guidance did not have a material impact on our financial position, results of operations, cash flow or business processes. However, the guidance introduced new disclosures which are presented below. The following table disaggregates our revenue from contracts with customers by customer type and segment and provides a reconciliation to total revenues for the period presented. Three Months Ended June 30, 2019 Nine Months Ended June 30, 2019 Distribution Pipeline and Storage Distribution Pipeline and Storage (In thousands) Gas sales revenues: Residential $ 269,484 $ — $ 1,513,239 $ — Commercial 113,591 — 611,474 — Industrial 25,277 — 95,701 — Public authority and other 6,305 — 36,677 — Total gas sales revenues 414,657 — 2,257,091 — Transportation revenues 22,923 166,864 76,005 456,558 Miscellaneous revenues 6,125 2,407 20,439 6,862 Revenues from contracts with customers 443,705 169,271 2,353,535 463,420 Alternative revenue program revenues 748 (20,073 ) (13,388 ) (44,102 ) Other revenues 491 — 1,521 — Total operating revenues $ 444,944 $ 149,198 $ 2,341,668 $ 419,318 Distribution Revenues Distribution revenues represent the delivery of natural gas to residential, commercial, industrial and public authority customers at prices based on tariff rates established by regulatory authorities in the states in which we operate. Revenue is recognized and our performance obligation is satisfied over time when natural gas is delivered and simultaneously consumed by our customer. We have elected to use the invoice practical expedient and recognize revenue for volumes delivered that we have the right to invoice our customers. We read meters and bill our customers on a monthly cycle basis. Accordingly, we estimate volumes from the last meter read to the balance sheet date and accrue revenue for gas delivered but not yet billed. In our Texas and Mississippi jurisdictions, we pay franchise fees and gross receipt taxes to operate in these service areas. These franchise fees and gross receipts taxes are required to be paid regardless of our ability to collect from our customers. Accordingly, we account for these amounts on a gross basis in revenue and we record the associated tax expense as a component of taxes, other than income. Pipeline and Storage Revenues Pipeline and storage revenues primarily represent the transportation and storage of natural gas on our Atmos Pipeline-Texas (APT) system and the transmission of natural gas through our 21-mile pipeline in Louisiana. APT provides transportation and storage services to our Mid-Tex Division, other third party local distribution companies and certain industrial customers under tariff rates approved by the Railroad Commission of Texas (RRC). APT also provides certain transportation and storage services to industrial and electric generation customers, as well as marketers and producers, under negotiated rates. Our pipeline in Louisiana is primarily used to aggregate gas supply for our Louisiana Division under a long-term contract and on a more limited basis to third parties. The demand fee charged to our Louisiana Division is subject to regulatory approval by the Louisiana Public Service Commission. We also manage two asset management plans with distribution affiliates of the Company at terms that have been approved by the applicable state regulatory commissions. The performance obligations for these transportation customers are satisfied by means of transporting customer-supplied gas to the designated location. Revenue is recognized and our performance obligation is satisfied over time when natural gas is delivered to the customer. Management determined that these arrangements qualify for the invoice practical expedient for recognizing revenue. For demand fee arrangements, revenue is recognized and our performance obligation is satisfied by standing ready to transport natural gas over the period of each individual month. Alternative Revenue Program Revenues In our distribution segment, we have weather-normalization adjustment mechanisms that serve to minimize the effects of weather on our contribution margin. 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 revenue benchmark of $69.4 million that was established in its most recent rate case. Differences between actual revenues and revenues calculated under these mechanisms adjust the amount billed to customers. These mechanisms are considered to be alternative revenue programs under accounting standards generally accepted in the United States as they are deemed to be contracts between us and our regulator. Accordingly, revenue under these mechanisms are excluded from revenue from contracts with customers.

Debt

Debt	9 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Debt	Debt The nature and terms of our debt instruments and credit facilities are described in detail in Note 5 to the consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2018 . Other than as described below, there were no material changes in the terms of our debt instruments during the nine months ended June 30, 2019 . Long-term debt at June 30, 2019 and September 30, 2018 consisted of the following: June 30, 2019 September 30, 2018 (In thousands) Unsecured 8.50% Senior Notes, due March 2019 $ — $ 450,000 Unsecured 3.00% Senior Notes, due 2027 500,000 500,000 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 — Unsecured 4.125% Senior Notes, due 2049 450,000 — 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 Floating-rate term loan, due September 2019 (1) 125,000 125,000 Total long-term debt 3,685,000 3,085,000 Less: Original issue (premium) / discount on unsecured senior notes and debentures 225 (4,439 ) Debt issuance cost 30,640 20,774 Current maturities 125,000 575,000 $ 3,529,135 $ 2,493,665 (1) Up to $200 million can be drawn under this term loan. On March 4, 2019, we completed a public offering of $450 million of 4.125% senior notes due 2049. The effective interest rate of these notes is 4.86% , after giving effect to the offering costs and the settlement of the associated forward starting interest rate swaps. The net proceeds, after the underwriting discount and offering expenses, of $443.4 million , together with available cash, was used to repay at maturity our $450 million 8.50% unsecured senior notes due March 15, 2019 and the related settlement of our interest rate swaps. On October 4, 2018, we completed a public offering of $600 million of 4.30% senior notes due 2048. We received net proceeds from the offering, after the underwriting discount and offering expenses, of $590.6 million , that were used to repay working capital borrowings pursuant to our commercial paper program. The effective interest rate of these notes is 4.37% after giving effect to the offering costs. 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. Changes in the price of natural gas and the amount of natural gas we need to supply our customers’ needs could significantly affect our borrowing requirements. Our short-term borrowings typically reach their highest levels in the winter months. Currently, our short-term borrowing requirements are satisfied through a combination of a $1.5 billion commercial paper program and three committed revolving credit facilities with third-party lenders that provide approximately $1.5 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 29, 2019, we executed our final one-year extension option which extended the maturity date from September 25, 2022 to September 25, 2023 . The facility bears interest at a base rate or at a LIBOR-based rate for the applicable interest period, plus a margin ranging from zero percent to 1.25 percent , 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 June 30, 2019 and September 30, 2018 , a total of $74.9 million and $575.8 million was outstanding under our commercial paper program. Additionally, we have a $25 million 364-day unsecured facility, which was renewed effective April 1, 2019 and expires March 31, 2020, and a $10 million 364-day unsecured revolving credit facility, which is used primarily to issue letters of credit. At June 30, 2019 , there were no borrowings outstanding under either of these facilities; however, outstanding letters of credit reduced the total amount available to us under our $10 million facility to $4.4 million . 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 June 30, 2019 , our total-debt-to-total-capitalization ratio, as defined in the agreements, was 41 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 June 30, 2019 . 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	9 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Shareholders' Equity and Accumulated Other Comprehensive Income	Shareholders' Equity The following tables present a reconciliation of changes in stockholders' equity for the three and nine months ended June 30, 2019 and 2018 . Common stock Additional Accumulated Retained Total Number of Stated (In thousands, except share and per share data) Balance, September 30, 2018 111,273,683 $ 556 $ 2,974,926 $ (83,647 ) $ 1,878,116 $ 4,769,951 Net income — — — — 157,646 157,646 Other comprehensive loss — — — (22,258 ) — (22,258 ) Cash dividends ($0.525 per share) — — — — (58,722 ) (58,722 ) Cumulative effect of accounting change (See Note 2) — — — (8,210 ) 8,210 — Common stock issued: Public and other stock offerings 5,434,812 27 498,948 — — 498,975 Stock-based compensation plans 184,464 1 2,602 — — 2,603 Balance, December 31, 2018 116,892,959 584 3,476,476 (114,115 ) 1,985,250 5,348,195 Net income — — — — 214,888 214,888 Other comprehensive loss — — — (2,695 ) — (2,695 ) Cash dividends ($0.525 per share) — — — — (61,606 ) (61,606 ) Common stock issued: Public and other stock offerings 61,006 1 5,453 — — 5,454 Stock-based compensation plans 28,938 — 3,865 — — 3,865 Balance, March 31, 2019 116,982,903 585 3,485,794 (116,810 ) 2,138,532 5,508,101 Net income — — — — 80,466 80,466 Other comprehensive income — — — 1,147 — 1,147 Cash dividends ($0.525 per share) — — — — (61,654 ) (61,654 ) Common stock issued: Public and other stock offerings 1,127,244 5 103,425 — — 103,430 Stock-based compensation plans 85,966 1 10,505 — — 10,506 Balance, June 30, 2019 118,196,113 $ 591 $ 3,599,724 $ (115,663 ) $ 2,157,344 $ 5,641,996 Common stock Additional Accumulated Retained Total Number of Stated (In thousands, except share and per share data) Balance, September 30, 2017 106,104,634 $ 531 $ 2,536,365 $ (105,254 ) $ 1,467,024 $ 3,898,666 Net income — — — — 314,132 314,132 Other comprehensive loss — — — (1,062 ) — (1,062 ) Cash dividends ($0.485 per share) — — — — (51,837 ) (51,837 ) Common stock issued: Public and other stock offerings 4,621,518 22 400,737 — — 400,759 Stock-based compensation plans 235,960 2 2,960 — — 2,962 Balance, December 31, 2017 110,962,112 555 2,940,062 (106,316 ) 1,729,319 4,563,620 Net income — — — — 178,992 178,992 Other comprehensive income — — — 21,305 — 21,305 Cash dividends ($0.485 per share) — — — — (54,054 ) (54,054 ) Common stock issued: Public and other stock offerings 76,776 — 6,235 — — 6,235 Stock-based compensation plans 21,440 — 5,248 — — 5,248 Balance, March 31, 2018 111,060,328 555 2,951,545 (85,011 ) 1,854,257 4,721,346 Net income — — — — 71,193 71,193 Other comprehensive income — — — 8,630 — 8,630 Cash dividends ($0.485 per share) — — — — (54,116 ) (54,116 ) Common stock issued: Public and other stock offerings 45,307 1 3,947 — — 3,948 Stock-based compensation plans 89,813 — 8,551 — — 8,551 Balance, June 30, 2018 111,195,448 $ 556 $ 2,964,043 $ (76,381 ) $ 1,871,334 $ 4,759,552 Shelf Registration, At-the-Market Equity Sales Program and Equity Issuances On November 13, 2018 , we filed a registration statement with the Securities and Exchange Commission (SEC) to issue, from time to time, up to $3.0 billion in common stock and/or debt securities, which expires November 13, 2021. This registration statement replaced our previous registration statement that was effectively exhausted in October 2018. At June 30, 2019 , approximately $1.3 billion of securities remained available for issuance under the shelf registration statement. On November 19, 2018 , we filed a prospectus supplement under the 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 $500 million (including shares of common stock that may be sold pursuant to a forward sale agreement entered into concurrently with the ATM equity sales program), which expires November 13, 2021. As of June 30, 2019 , the ATM program had approximately $231 million of equity available for issuance. On November 30, 2018 , we filed a prospectus supplement under the registration statement relating to an underwriting agreement to sell 5,390,836 shares of our common stock for $500 million . After expenses, net proceeds from the offering were $494.1 million . Concurrently, we entered into separate forward sale agreements with two forward sellers, collectively referred to as the block. The following table presents information relevant to the forward sales during fiscal year 2019. Maturity September 30, 2020 March 31, 2020 Total Shares Price (1) Proceeds Shares Price (1) Proceeds Shares Price (1) Proceeds (in millions) Available Balance September 30, 2018 — $ — $ — — $ — $ — — $ — $ — Issued via Block — — 2,668,464 91.77 2,668,464 91.77 Available Balance December 31, 2018 (2) — — — 2,668,464 91.90 245.2 2,668,464 91.90 245.2 Issued via ATM — — 1,670,509 95.46 1,670,509 95.46 Available Balance March 31, 2019 (2) — — — 4,338,973 93.08 403.9 4,338,973 93.08 403.9 Issued via ATM 1,050,563 101.41 — — 1,050,563 101.41 Settled Block — — (1,089,700 ) 91.44 (1,089,700 ) 91.44 Available Balance June 30, 2019 (2) 1,050,563 $ 101.11 $ 106.2 3,249,273 $ 93.34 $ 303.3 4,299,836 $ 95.24 $ 409.5 (1) Issued price as disclosed is calculated as the weighted average price for activity occurring during the quarter. (2) If we had settled all shares available under the forward agreements as of the period end, including forward price adjustments, we would receive proceeds based on the stated net price. On November 30, 2017, we filed a prospectus supplement under the previous registration statement relating to an underwriting agreement to sell 4,558,404 shares of our common stock for $400 million . After expenses, net proceeds from the offering were $395.1 million . 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- for-Sale Securities (1) Interest Rate Agreement Cash Flow Hedges Total (In thousands) September 30, 2018 $ 8,124 $ (91,771 ) $ (83,647 ) Other comprehensive income (loss) before reclassifications 192 (25,966 ) (25,774 ) Amounts reclassified from accumulated other comprehensive income (1 ) 1,969 1,968 Net current-period other comprehensive income (loss) 191 (23,997 ) (23,806 ) Cumulative effect of accounting change (See Note 2) (8,210 ) — (8,210 ) June 30, 2019 $ 105 $ (115,768 ) $ (115,663 ) Available- for-Sale Securities (1) Interest Rate Agreement Cash Flow Hedges Total (In thousands) September 30, 2017 $ 7,048 $ (112,302 ) $ (105,254 ) Other comprehensive income before reclassifications 148 28,315 28,463 Amounts reclassified from accumulated other comprehensive income (884 ) 1,294 410 Net current-period other comprehensive income (loss) (736 ) 29,609 28,873 June 30, 2018 $ 6,312 $ (82,693 ) $ (76,381 ) (1) Available-for-sale-securities reported in fiscal 2018 include both debt and equity securities, while fiscal 2019 includes only debt securities. See Note 2 for further discussion regarding our adoption of the new accounting standard.

Interim Pension and Other Postr

Interim Pension and Other Postretirement Benefit Plan Information	9 Months Ended
	Jun. 30, 2019
Retirement Benefits, Description [Abstract]
Interim Pension and Other Postretirement Benefit Plan Information	Interim Pension and Other Postretirement Benefit Plan Information The components of our net periodic pension cost for our pension and other postretirement benefit plans for the three and nine months ended June 30, 2019 and 2018 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 June 30 Pension Benefits Other Benefits 2019 2018 2019 2018 (In thousands) Components of net periodic pension cost: Service cost $ 4,044 $ 4,794 $ 2,702 $ 3,020 Interest cost (1) 6,799 6,448 2,960 2,726 Expected return on assets (1) (7,113 ) (6,917 ) (2,664 ) (2,002 ) Amortization of prior service cost (credit) (1) (57 ) (57 ) 43 2 Amortization of actuarial (gain) loss (1) 1,606 3,050 (2,045 ) (1,618 ) Settlements (1) — 888 — — Net periodic pension cost $ 5,279 $ 8,206 $ 996 $ 2,128 Nine Months Ended June 30 Pension Benefits Other Benefits 2019 2018 2019 2018 (In thousands) Components of net periodic pension cost: Service cost $ 12,134 $ 13,929 $ 8,107 $ 9,059 Interest cost (1) 20,399 19,311 8,879 8,180 Expected return on assets (1) (21,339 ) (20,750 ) (7,994 ) (6,005 ) Amortization of prior service cost (credit) (1) (173 ) (173 ) 130 8 Amortization of actuarial (gain) loss (1) 4,821 9,224 (6,134 ) (4,855 ) Settlements (1) — 3,303 — — Net periodic pension cost $ 15,842 $ 24,844 $ 2,988 $ 6,387 (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 statement of comprehensive income or are capitalized on the condensed consolidated balance sheets as a regulatory asset or liability, as described in Note 2.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Jun. 30, 2019
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) is investigating an incident that occurred at a Dallas, Texas residence on February 23, 2018 that resulted in one fatality and injuries to four other residents. Together with the Railroad Commission of Texas (RRC) and the Pipeline and Hazardous Materials Safety Administration, Atmos Energy is a party to the investigation and in that capacity is working closely with the NTSB to help determine the cause of this incident. On March 29, 2018 , a civil action was filed in Dallas, Texas against Atmos Energy in response to the February 23rd incident. In May 2019, the parties resolved the civil action to their mutual satisfaction subject to our self-insured retention noted above. 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. These purchase commitment contracts are detailed in our Annual Report on Form 10-K for the fiscal year ended September 30, 2018 . At June 30, 2019 , we were committed to purchase 53.9 Bcf within one year and 1.8 Bcf within two to three years under indexed contracts. Leases We have entered into operating leases for towers, office and warehouse space, vehicles and heavy equipment used in our operations. During the nine months ended June 30, 2019 , we executed amendments to some of our lease agreements that impacted terms as well as our future minimum lease payments. As of June 30, 2019 , the remaining lease terms range from one to 20 years and generally provide for the payment of taxes, insurance and maintenance by the lessee. Renewal options exist for certain of these leases. The related future minimum lease payments at June 30, 2019 totaled $194.9 million . Rate Regulatory Proceedings Except for routine rate regulatory proceedings as discussed below, there were no material changes to rate regulatory proceedings for the nine months ended June 30, 2019 . As of June 30, 2019 , rate regulatory proceedings were in progress in some of our service areas. These rate regulatory proceedings are discussed in further detail below in Management’s Discussion and Analysis — Recent Ratemaking Developments . Additionally, as discussed in further detail in Note 13

Financial Instruments

Financial Instruments	9 Months Ended
	Jun. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instruments	Financial Instruments We currently use financial instruments to mitigate commodity price risk and in the past have also used financial instruments to mitigate 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 13 to the consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2018 . During the nine months ended June 30, 2019 , 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 2018 - 2019 heating season (generally October through March), in the jurisdictions where we are permitted to utilize financial instruments, we hedged approximately 33 percent , or 18.9 Bcf of the winter flowing gas requirements. We have not designated these financial instruments as hedges for accounting purposes. Interest Rate Risk Management Activities Historically, we managed interest rate risk by periodically entering into financial instruments to effectively fix the Treasury yield component of the interest cost associated with anticipated financings. In fiscal 2014 and 2015, we entered into forward starting interest rate swaps to fix the Treasury yield component associated with $450 million of the then anticipated issuance of $450 million unsecured senior notes in fiscal 2019. These notes were issued as planned in March 2019 and we settled the swaps with the payment of $90.1 million . Because the swaps were effective, the realized loss was recorded as a component of AOCI and is being recognized as a component of interest expense over the 30-year life of the senior notes. As of June 30, 2019 , we had $115.8 million of net realized losses in AOCI associated with the settlement of financial instruments used to fix the Treasury yield component of the interest cost of financing various issuances of long-term debt and senior notes, which will be recognized as a component of interest expense over the life of the associated notes from the date of settlement. The remaining amortization periods for these settled amounts extend through fiscal 2049. 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 June 30, 2019 , 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 June 30, 2019 , we had 16,784 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 June 30, 2019 and September 30, 2018 . 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, for June 30, 2019 and September 30, 2018 , no gross amounts and no cash collateral were netted within our consolidated balance sheet. Balance Sheet Location Assets Liabilities (In thousands) June 30, 2019 Not Designated As Hedges: Commodity contracts Other current assets / Other current liabilities $ 2,408 $ (3,358 ) Commodity contracts Deferred charges and other assets / Deferred credits and other liabilities 149 (513 ) Total 2,557 (3,871 ) Gross / Net Financial Instruments $ 2,557 $ (3,871 ) Balance Sheet Location Assets Liabilities (In thousands) September 30, 2018 Designated As Hedges: Interest rate swaps Other current assets / $ — $ (56,499 ) Total — (56,499 ) Not Designated As Hedges: Commodity contracts Other current assets / Other current liabilities 1,369 (235 ) Commodity contracts Deferred charges and other assets / Deferred credits and other liabilities 250 (103 ) Total 1,619 (338 ) Gross / Net Financial Instruments $ 1,619 $ (56,837 ) Impact of Financial Instruments on the Statement of Comprehensive Income Cash Flow Hedges As discussed above, in the past our distribution segment had 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 June 30, 2019 and 2018 was $1.4 million and $0.6 million and for the nine months ended June 30, 2019 and 2018 was $2.6 million and $1.8 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 nine months ended June 30, 2019 and 2018 . 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 June 30 Nine Months Ended June 30 2019 2018 2019 2018 (In thousands) Increase (decrease) in fair value: Interest rate agreements $ — $ 7,861 $ (25,966 ) $ 28,315 Recognition of losses in earnings due to settlements: Interest rate agreements 1,053 459 1,969 1,294 Total other comprehensive income (loss) from hedging, net of tax $ 1,053 $ 8,320 $ (23,997 ) $ 29,609 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. The following amounts, net of deferred taxes, represent the expected recognition in earnings, as of June 30, 2019 , of the deferred losses recorded in AOCI associated with our financial instruments, based upon the fair values of these financial instruments at the date of settlement. Interest Rate Agreements (In thousands) Next twelve months $ (4,212 ) Thereafter (111,556 ) Total $ (115,768 ) 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	9 Months Ended
	Jun. 30, 2019
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 financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2018 . During the nine months ended June 30, 2019 , 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 7 to the financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2018 . 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 June 30, 2019 and September 30, 2018 . Assets and liabilities are categorized in their entirety based on the lowest level of input that is significant to the fair value measurement. Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) (1) Significant Other Unobservable Inputs (Level 3) Netting and Cash Collateral June 30, 2019 (In thousands) Assets: Financial instruments $ — $ 2,557 $ — $ — $ 2,557 Debt and equity securities Registered investment companies 43,798 — — — 43,798 Bond mutual funds 25,778 — — — 25,778 Bonds (2) — 31,097 — — 31,097 Money market funds — 1,369 — — 1,369 Total debt and equity securities 69,576 32,466 — — 102,042 Total assets $ 69,576 $ 35,023 $ — $ — $ 104,599 Liabilities: Financial instruments $ — $ 3,871 $ — $ — $ 3,871 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) (1) Significant Other Unobservable Inputs (Level 3) Netting and Cash Collateral September 30, 2018 (In thousands) Assets: Financial instruments $ — $ 1,619 $ — $ — $ 1,619 Debt and equity securities Registered investment companies 42,644 — — — 42,644 Bond mutual funds 21,507 — — — 21,507 Bonds (2) — 31,400 — — 31,400 Money market funds — 3,834 — — 3,834 Total debt and equity securities 64,151 35,234 — — 99,385 Total assets $ 64,151 $ 36,853 $ — $ — $ 101,004 Liabilities: Financial instruments $ — $ 56,837 $ — $ — $ 56,837 (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 as described in Note 2. Debt and equity securities are comprised of our available-for-sale debt securities and our equity securities. We regularly 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 and current returns. If a determination is made that a decline in fair value is other than temporary, the related investment is written down to its estimated fair value and the other-than-temporary impairment is recognized in the statement of comprehensive income. At June 30, 2019 and September 30, 2018 , our available-for-sale debt securities amortized cost was $31.0 million and $31.5 million . At June 30, 2019 , we maintained investments in bonds that have contractual maturity dates ranging from July 2019 through February 2022. Other Fair Value Measures Our debt is recorded at carrying value. The fair value of our debt 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 following table presents the carrying value and fair value of our debt as of June 30, 2019 and September 30, 2018 : June 30, 2019 September 30, 2018 (In thousands) Carrying Amount $ 3,685,000 $ 3,085,000 Fair Value $ 4,144,253 $ 3,161,679

Concentration of Credit Risk

Concentration of Credit Risk	9 Months Ended
	Jun. 30, 2019
Risks and Uncertainties [Abstract]
Concentration of Credit Risk	Concentration of Credit Risk Information regarding our concentration of credit risk is disclosed in Note 16 to the financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2018 . During the nine months ended June 30, 2019 , there were no material changes in our concentration of credit risk.

Impact of the Tax Cuts and Jobs

Impact of the Tax Cuts and Jobs Act of 2017	9 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Impact of the Tax Cuts and Jobs Act of 2017	Impact of the Tax Cuts and Jobs Act of 2017 On December 22, 2017, the Tax Cuts and Jobs Act of 2017 (the "TCJA") was signed into law. As a result of the implementation of the TCJA, we recognized a $165.5 million income tax benefit in our condensed consolidated statement of comprehensive income during the nine months ended June 30, 2018 related to a change in deferred taxes that were not related to our cost of service ratemaking. The change in deferred taxes related to our cost of service ratemaking (referred to as excess deferred taxes) was reclassified into a regulatory liability and will be returned to ratepayers in accordance with regulatory requirements. As of June 30, 2019 and September 30, 2018 , this liability totaled $731.8 million and $744.9 million . We have worked and continue to work with our regulators in each jurisdiction to fully incorporate the effects of the TCJA into customer bills. As of June 30, 2019 , we have received approval from regulators to update our cost of service rates to reflect the decrease in the statutory income tax rate in all of our service areas. Regulators in all of our service areas issued accounting orders that required us to establish, effective January 1, 2018, a separate regulatory liability for the difference in taxes included in our rates that were calculated based on a 35% statutory income tax rate and rates based on the new 21% statutory income tax rate until the new rates could be established. As of June 30, 2019 , we received approval from substantially all regulators to return these liabilities to customers. This regulatory liability totaled $6.1 million and $22.5 million as of June 30, 2019 and September 30, 2018 . As of June 30, 2019 , we received approval from regulators to return excess deferred taxes in most of our jurisdictions in accordance with regulatory proceedings on a provisional basis over periods ranging from 13 to 51 years. In our remaining jurisdictions, the treatment of the effects of the TCJA in rates is being addressed in ongoing or will be addressed in future regulatory proceedings. The SEC issued guidance in Staff Accounting Bulletin 118 (SAB 118), which allowed us to record provisional amounts during a one-year measurement period, similar to the measurement period in accounting for business combinations. The Company recorded provisional amounts for the income tax effects of the TCJA for the fiscal year ended September 30, 2018. Although the Company no longer considers the accounting effects of the TCJA to be provisional under SAB 118, many aspects of the TCJA remain unclear and its impact on the Company's income tax balances may change following further interpretation of TCJA provisions by issuance of U.S. Treasury regulations or guidance from the Internal Revenue Service. We continue to monitor and assess the accounting implications of the TCJA developments on the consolidated financial statements.

Unaudited Financial Informati_2

Unaudited Financial Information (Policies)	9 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Significant accounting policies	Accounting pronouncements adopted in fiscal 2019 During the first quarter of fiscal 2019, we adopted the following accounting guidance updates, effective October 1, 2018. The adoption of this new guidance, individually and collectively, did not have a material impact on our financial position, results of operations or cash flows. • Revenue recognition - Under the new guidance, we are required to recognize revenue when we transfer promised goods or services to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those goods or services. See Note 5 for our discussion of the effects of implementing this standard. • Classification and measurement of financial instruments - The new guidance requires that we recognize changes in the fair value of our equity securities formerly designated as available-for-sale in other non-operating income (expense) in our condensed consolidated statement of comprehensive income on a prospective basis from the date of adoption. However, we continue to classify cash flows from purchases and sales of equity securities within investing activities given the nature of these securities. Additionally, in accordance with the guidance, we reclassified a net $8.2 million unrealized gain related to these equity securities from accumulated other comprehensive income (AOCI) to retained earnings. The accounting for debt securities designated as available-for-sale did not change as a result of this new guidance. Accordingly, changes in the fair value of these securities will continue to be recorded as a component of AOCI. • Presentation of the Components of Net Periodic Benefit Cost - The new guidance requires us to present only the current service cost component of the net benefit cost within operations and maintenance expense in the statement of comprehensive income. The remaining components of net benefit cost are now recorded in other non-operating income (expense) in our condensed consolidated statements of comprehensive income. The change in presentation of these costs was implemented on a retrospective basis as required by the guidance. In lieu of determining how each component of the net periodic benefit cost was actually reflected in the prior periods’ condensed statement of comprehensive income, we elected to utilize a practical expedient that permits the use of the amounts disclosed for these costs in our pension and post-retirement benefit plans footnote as the basis to retroactively apply this standard. In addition, under the new guidance, only the service cost component of net benefit cost is eligible for capitalization (e.g., as part of inventory or property, plant, and equipment). We continue to capitalize these costs into property, plant and equipment. However, the Federal Energy Regulatory Commission (FERC), which establishes the regulatory accounting practices for rate-regulated entities, issued guidance that permits such entities the option to continue to capitalize non-service benefit costs for regulatory purposes. Since the accounting guidelines by the FERC are typically followed by our state regulatory authorities, for U.S. GAAP reporting purposes, we are prospectively deferring into a regulatory asset the portion of non-service components of net periodic benefit cost that are capitalizable for regulatory purposes. • Accounting for Implementation Costs Incurred in A Hosting Arrangement That Is A Service Contract - The new guidance aligns the requirements for capitalizing implementation costs incurred for these contracts with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). We elected to early adopt the new guidance on a prospective basis. Accordingly, we will capitalize the up-front costs incurred for cloud computing arrangements had they been capitalizable in a similar on-premise software solution. Accounting pronouncements that will be effective after fiscal 2019 In February 2016, the Financial Accounting Standards Board (FASB) issued a comprehensive new leasing standard that will require lessees to recognize a lease liability and a right-of-use asset for all leases, including operating leases, with a term greater than 12 months on its balance sheet. Subsequently, the FASB issued practical expedients to 1) allow entities to not evaluate existing or expired land easements that were not previously accounted for as leases under the current guidance and 2) allow entities the option to adopt the standard and recognize a cumulative–effect adjustment to the opening balance of retained earnings in the period of adoption rather than applying the new guidance at the beginning of the earliest comparative period presented in the year of adoption. The new standard will be effective for us beginning on October 1, 2019. The impact of this change on our financial position is not reasonably estimable at this time. We do not anticipate the adoption of this standard will have a material impact to our results of operations or cash flows. We continue to evaluate our adoption of certain practical expedients, however we currently anticipate adopting the following practical expedients: • land easements under the provisions of ASU 2018-01, as described above, • package of three practical expedients described in ASC 842-10-65-1 and • transition method practical expedient provided in ASU 2018-11, as described above. We are implementing a new lease accounting system, which we will utilize to capture, track and account for lease data. The new system will also aid in automating the compilation of disclosure information. In June 2016, the FASB issued new guidance which will require credit losses on most financial assets measured at amortized cost and certain other instruments to be measured using an expected credit loss model. Under this model, entities will estimate credit losses over the entire contractual term of the instrument from the date of initial recognition of that instrument. In contrast, current U.S. GAAP is based on an incurred loss model that delays recognition of credit losses until it is probable the loss has been incurred. The new guidance also introduces a new impairment recognition model for available-for-sale debt securities that will require credit losses for available-for-sale debt securities to be recorded through an allowance account. The new standard will be effective for us beginning on October 1, 2020; early adoption is permitted. We are currently evaluating the potential impact of this new guidance on our financial position, results of operations and cash flows. In August 2018, the FASB issued new guidance that modifies the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. The guidance removes the disclosure requirements for the amounts of gain/loss and prior service cost/credit amortization expected in the following year and the disclosure of the effect of a one-percentage-point change in the health care cost trend rate, among other changes. The guidance adds certain disclosures including the weighted average interest crediting rate for cash balance plans and a narrative description for the significant change in gains and losses as well as any other significant change in the plan obligations or assets. The new guidance is effective for us in the fiscal year beginning October 1, 2020 and should be applied on a retrospective basis to all periods presented. Early adoption is permitted. The adoption of this new guidance impacts only our disclosures. We intend to early adopt the guidance as of September 30, 2019.
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 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 and our regulatory excess deferred taxes and regulatory cost of removal obligation are reported separately.
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
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 financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2018 . During the nine months ended June 30, 2019 , there were no changes in these methods.
Revenue from Contract with Customer	Distribution Revenues Distribution revenues represent the delivery of natural gas to residential, commercial, industrial and public authority customers at prices based on tariff rates established by regulatory authorities in the states in which we operate. Revenue is recognized and our performance obligation is satisfied over time when natural gas is delivered and simultaneously consumed by our customer. We have elected to use the invoice practical expedient and recognize revenue for volumes delivered that we have the right to invoice our customers. We read meters and bill our customers on a monthly cycle basis. Accordingly, we estimate volumes from the last meter read to the balance sheet date and accrue revenue for gas delivered but not yet billed. In our Texas and Mississippi jurisdictions, we pay franchise fees and gross receipt taxes to operate in these service areas. These franchise fees and gross receipts taxes are required to be paid regardless of our ability to collect from our customers. Accordingly, we account for these amounts on a gross basis in revenue and we record the associated tax expense as a component of taxes, other than income. Pipeline and Storage Revenues Pipeline and storage revenues primarily represent the transportation and storage of natural gas on our Atmos Pipeline-Texas (APT) system and the transmission of natural gas through our 21-mile pipeline in Louisiana. APT provides transportation and storage services to our Mid-Tex Division, other third party local distribution companies and certain industrial customers under tariff rates approved by the Railroad Commission of Texas (RRC). APT also provides certain transportation and storage services to industrial and electric generation customers, as well as marketers and producers, under negotiated rates. Our pipeline in Louisiana is primarily used to aggregate gas supply for our Louisiana Division under a long-term contract and on a more limited basis to third parties. The demand fee charged to our Louisiana Division is subject to regulatory approval by the Louisiana Public Service Commission. We also manage two asset management plans with distribution affiliates of the Company at terms that have been approved by the applicable state regulatory commissions. The performance obligations for these transportation customers are satisfied by means of transporting customer-supplied gas to the designated location. Revenue is recognized and our performance obligation is satisfied over time when natural gas is delivered to the customer. Management determined that these arrangements qualify for the invoice practical expedient for recognizing revenue. For demand fee arrangements, revenue is recognized and our performance obligation is satisfied by standing ready to transport natural gas over the period of each individual month.
Revenue Recognition for Alternative Revenue Programs	Alternative Revenue Program Revenues In our distribution segment, we have weather-normalization adjustment mechanisms that serve to minimize the effects of weather on our contribution margin. 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 revenue benchmark of $69.4 million that was established in its most recent rate case. Differences between actual revenues and revenues calculated under these mechanisms adjust the amount billed to customers. These mechanisms are considered to be alternative revenue programs under accounting standards generally accepted in the United States as they are deemed to be contracts between us and our regulator. Accordingly, revenue under these mechanisms are excluded from revenue from contracts with customers.

Unaudited Financial Informati_3

Unaudited Financial Information (Table)	9 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Schedule of Regulatory Assets	Significant regulatory assets and liabilities as of June 30, 2019 and September 30, 2018 included the following: June 30, September 30, (In thousands) Regulatory assets: Pension and postretirement benefit costs $ 8,007 $ 6,496 Infrastructure mechanisms (1) 111,211 96,739 Deferred gas costs 7,227 1,927 Recoverable loss on reacquired debt 7,000 8,702 Deferred pipeline record collection costs 25,347 20,467 Rate case costs 1,413 2,741 Other 4,465 6,739 $ 164,670 $ 143,811 Regulatory liabilities: Regulatory excess deferred taxes (2) $ 731,837 $ 744,895 Regulatory cost of service reserve (3) 6,079 22,508 Regulatory cost of removal obligation 526,403 522,175 Deferred gas costs 66,171 94,705 Asset retirement obligation 12,887 12,887 APT annual adjustment mechanism 63,130 35,228 Pension and postretirement benefit costs 80,330 69,113 Other 3,038 9,486 $ 1,489,875 $ 1,510,997 (1) Infrastructure mechanisms in Texas and Louisiana 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) The TCJA resulted in the remeasurement of the net deferred tax liability included in our rate base. Of this amount, $21.9 million as of June 30, 2019 and $5.2 million as of September 30, 2018 is recorded in other current liabilities. The period and timing of the return of the excess deferred taxes is being determined by regulators in each of our jurisdictions. See Note 13 for further information. (3) Effective January 1, 2018, regulators in each of our service areas required us to establish a regulatory liability for the difference in recoverable federal taxes included in revenues based on the former 35% federal statutory rate and the new 21% federal statutory rate for service provided on or after January 1, 2018. The period and timing of the return of this liability to utility customers is being determined by regulators in each of our jurisdictions. See Note 13
Schedule of Regulatory Liabilities	Significant regulatory assets and liabilities as of June 30, 2019 and September 30, 2018 included the following: June 30, September 30, (In thousands) Regulatory assets: Pension and postretirement benefit costs $ 8,007 $ 6,496 Infrastructure mechanisms (1) 111,211 96,739 Deferred gas costs 7,227 1,927 Recoverable loss on reacquired debt 7,000 8,702 Deferred pipeline record collection costs 25,347 20,467 Rate case costs 1,413 2,741 Other 4,465 6,739 $ 164,670 $ 143,811 Regulatory liabilities: Regulatory excess deferred taxes (2) $ 731,837 $ 744,895 Regulatory cost of service reserve (3) 6,079 22,508 Regulatory cost of removal obligation 526,403 522,175 Deferred gas costs 66,171 94,705 Asset retirement obligation 12,887 12,887 APT annual adjustment mechanism 63,130 35,228 Pension and postretirement benefit costs 80,330 69,113 Other 3,038 9,486 $ 1,489,875 $ 1,510,997 (1) Infrastructure mechanisms in Texas and Louisiana 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) The TCJA resulted in the remeasurement of the net deferred tax liability included in our rate base. Of this amount, $21.9 million as of June 30, 2019 and $5.2 million as of September 30, 2018 is recorded in other current liabilities. The period and timing of the return of the excess deferred taxes is being determined by regulators in each of our jurisdictions. See Note 13 for further information. (3) Effective January 1, 2018, regulators in each of our service areas required us to establish a regulatory liability for the difference in recoverable federal taxes included in revenues based on the former 35% federal statutory rate and the new 21% federal statutory rate for service provided on or after January 1, 2018. The period and timing of the return of this liability to utility customers is being determined by regulators in each of our jurisdictions. See Note 13 for further information.

Segment Information (Table)

Segment Information (Table)	9 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Income statements and capital expenditures for the three and nine months ended June 30, 2019 and 2018 by segment are presented in the following tables: Three Months Ended June 30, 2019 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 444,287 $ 41,451 $ — $ 485,738 Intersegment revenues 657 107,747 (108,404 ) — Total operating revenues 444,944 149,198 (108,404 ) 485,738 Purchased gas cost 139,518 (96 ) (108,096 ) 31,326 Operation and maintenance expense 123,998 40,855 (308 ) 164,545 Depreciation and amortization expense 70,611 27,089 — 97,700 Taxes, other than income 62,134 7,831 — 69,965 Operating income 48,683 73,519 — 122,202 Other non-operating income (expense) 3,005 (1,360 ) — 1,645 Interest charges 10,597 8,995 — 19,592 Income before income taxes 41,091 63,164 — 104,255 Income tax expense 8,693 15,096 — 23,789 Net income $ 32,398 $ 48,068 $ — $ 80,466 Capital expenditures $ 316,825 $ 104,788 $ — $ 421,613 Three Months Ended June 30, 2018 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 534,816 $ 27,429 $ — $ 562,245 Intersegment revenues 672 100,204 (100,876 ) — Total operating revenues 535,488 127,633 (100,876 ) 562,245 Purchased gas cost 230,887 561 (100,562 ) 130,886 Operation and maintenance expense 110,568 33,494 (314 ) 143,748 Depreciation and amortization expense 66,504 24,167 — 90,671 Taxes, other than income 64,420 8,200 — 72,620 Operating income 63,109 61,211 — 124,320 Other non-operating expense (2,518 ) (812 ) — (3,330 ) Interest charges 13,315 10,034 — 23,349 Income before income taxes 47,276 50,365 — 97,641 Income tax expense 11,932 14,516 — 26,448 Net income $ 35,344 $ 35,849 $ — $ 71,193 Capital expenditures $ 284,209 $ 110,285 $ — $ 394,494 Nine Months Ended June 30, 2019 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 2,339,660 $ 118,505 $ — $ 2,458,165 Intersegment revenues 2,008 300,813 (302,821 ) — Total operating revenues 2,341,668 419,318 (302,821 ) 2,458,165 Purchased gas cost 1,147,598 (544 ) (301,887 ) 845,167 Operation and maintenance expense 347,386 106,120 (934 ) 452,572 Depreciation and amortization expense 210,224 80,313 — 290,537 Taxes, other than income 189,377 24,169 — 213,546 Operating income 447,083 209,260 — 656,343 Other non-operating income (expense) 1,791 (3,637 ) — (1,846 ) Interest charges 44,703 29,687 — 74,390 Income before income taxes 404,171 175,936 — 580,107 Income tax expense 85,195 41,912 — 127,107 Net income $ 318,976 $ 134,024 $ — $ 453,000 Capital expenditures $ 912,640 $ 286,559 $ — $ 1,199,199 Nine Months Ended June 30, 2018 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 2,593,578 $ 77,268 $ — $ 2,670,846 Intersegment revenues 1,993 297,783 (299,776 ) — Total operating revenues 2,595,571 375,051 (299,776 ) 2,670,846 Purchased gas cost 1,421,698 1,906 (298,841 ) 1,124,763 Operation and maintenance expense 343,860 89,027 (935 ) 431,952 Depreciation and amortization expense 197,587 70,839 — 268,426 Taxes, other than income 184,219 24,181 — 208,400 Operating income 448,207 189,098 — 637,305 Other non-operating expense (5,961 ) (2,093 ) — (8,054 ) Interest charges 51,581 30,581 — 82,162 Income before income taxes 390,665 156,424 — 547,089 Income tax (benefit) expense (39,021 ) 21,793 — (17,228 ) Net income $ 429,686 $ 134,631 $ — $ 564,317 Capital expenditures $ 749,693 $ 338,779 $ — $ 1,088,472 Balance sheet information at June 30, 2019 and September 30, 2018 by segment is presented in the following tables: June 30, 2019 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Property, plant and equipment, net $ 8,404,238 $ 2,936,358 $ — $ 11,340,596 Total assets $ 12,083,315 $ 3,174,516 $ (2,376,733 ) $ 12,881,098 September 30, 2018 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Property, plant and equipment, net $ 7,644,693 $ 2,726,454 $ — $ 10,371,147 Total assets $ 11,109,128 $ 2,963,480 $ (2,198,171 ) $ 11,874,437

Earnings Per Share (Table)

Earnings Per Share (Table)	9 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	Basic and diluted earnings per share for the three and nine months ended June 30, 2019 and 2018 are calculated as follows: Three Months Ended June 30 Nine Months Ended June 30 2019 2018 2019 2018 (In thousands, except per share amounts) Basic Earnings Per Share Net income $ 80,466 $ 71,193 $ 453,000 $ 564,317 Less: Income allocated to participating securities 64 59 386 545 Income available to common shareholders $ 80,402 $ 71,134 $ 452,614 $ 563,772 Basic weighted average shares outstanding 118,075 111,851 116,485 110,707 Net income per share — Basic $ 0.68 $ 0.64 $ 3.89 $ 5.09 Diluted Earnings Per Share Income available to common shareholders $ 80,402 $ 71,134 $ 452,614 $ 563,772 Effect of dilutive shares — — — — Income available to common shareholders $ 80,402 $ 71,134 $ 452,614 $ 563,772 Basic weighted average shares outstanding 118,075 111,851 116,485 110,707 Dilutive shares 355 — 188 — Diluted weighted average shares outstanding 118,430 111,851 116,673 110,707 Net income per share - Diluted $ 0.68 $ 0.64 $ 3.88 $ 5.09

Revenue (Table)

Revenue (Table)	9 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table disaggregates our revenue from contracts with customers by customer type and segment and provides a reconciliation to total revenues for the period presented. Three Months Ended June 30, 2019 Nine Months Ended June 30, 2019 Distribution Pipeline and Storage Distribution Pipeline and Storage (In thousands) Gas sales revenues: Residential $ 269,484 $ — $ 1,513,239 $ — Commercial 113,591 — 611,474 — Industrial 25,277 — 95,701 — Public authority and other 6,305 — 36,677 — Total gas sales revenues 414,657 — 2,257,091 — Transportation revenues 22,923 166,864 76,005 456,558 Miscellaneous revenues 6,125 2,407 20,439 6,862 Revenues from contracts with customers 443,705 169,271 2,353,535 463,420 Alternative revenue program revenues 748 (20,073 ) (13,388 ) (44,102 ) Other revenues 491 — 1,521 — Total operating revenues $ 444,944 $ 149,198 $ 2,341,668 $ 419,318

Debt (Table)

Debt (Table)	9 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	Long-term debt at June 30, 2019 and September 30, 2018 consisted of the following: June 30, 2019 September 30, 2018 (In thousands) Unsecured 8.50% Senior Notes, due March 2019 $ — $ 450,000 Unsecured 3.00% Senior Notes, due 2027 500,000 500,000 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 — Unsecured 4.125% Senior Notes, due 2049 450,000 — 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 Floating-rate term loan, due September 2019 (1) 125,000 125,000 Total long-term debt 3,685,000 3,085,000 Less: Original issue (premium) / discount on unsecured senior notes and debentures 225 (4,439 ) Debt issuance cost 30,640 20,774 Current maturities 125,000 575,000 $ 3,529,135 $ 2,493,665 (1) Up to $200 million can be drawn under this term loan.

Shareholders' Equity (Table)

Shareholders' Equity (Table)	9 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Schedule of Stockholders Equity	The following tables present a reconciliation of changes in stockholders' equity for the three and nine months ended June 30, 2019 and 2018 . Common stock Additional Accumulated Retained Total Number of Stated (In thousands, except share and per share data) Balance, September 30, 2018 111,273,683 $ 556 $ 2,974,926 $ (83,647 ) $ 1,878,116 $ 4,769,951 Net income — — — — 157,646 157,646 Other comprehensive loss — — — (22,258 ) — (22,258 ) Cash dividends ($0.525 per share) — — — — (58,722 ) (58,722 ) Cumulative effect of accounting change (See Note 2) — — — (8,210 ) 8,210 — Common stock issued: Public and other stock offerings 5,434,812 27 498,948 — — 498,975 Stock-based compensation plans 184,464 1 2,602 — — 2,603 Balance, December 31, 2018 116,892,959 584 3,476,476 (114,115 ) 1,985,250 5,348,195 Net income — — — — 214,888 214,888 Other comprehensive loss — — — (2,695 ) — (2,695 ) Cash dividends ($0.525 per share) — — — — (61,606 ) (61,606 ) Common stock issued: Public and other stock offerings 61,006 1 5,453 — — 5,454 Stock-based compensation plans 28,938 — 3,865 — — 3,865 Balance, March 31, 2019 116,982,903 585 3,485,794 (116,810 ) 2,138,532 5,508,101 Net income — — — — 80,466 80,466 Other comprehensive income — — — 1,147 — 1,147 Cash dividends ($0.525 per share) — — — — (61,654 ) (61,654 ) Common stock issued: Public and other stock offerings 1,127,244 5 103,425 — — 103,430 Stock-based compensation plans 85,966 1 10,505 — — 10,506 Balance, June 30, 2019 118,196,113 $ 591 $ 3,599,724 $ (115,663 ) $ 2,157,344 $ 5,641,996 Common stock Additional Accumulated Retained Total Number of Stated (In thousands, except share and per share data) Balance, September 30, 2017 106,104,634 $ 531 $ 2,536,365 $ (105,254 ) $ 1,467,024 $ 3,898,666 Net income — — — — 314,132 314,132 Other comprehensive loss — — — (1,062 ) — (1,062 ) Cash dividends ($0.485 per share) — — — — (51,837 ) (51,837 ) Common stock issued: Public and other stock offerings 4,621,518 22 400,737 — — 400,759 Stock-based compensation plans 235,960 2 2,960 — — 2,962 Balance, December 31, 2017 110,962,112 555 2,940,062 (106,316 ) 1,729,319 4,563,620 Net income — — — — 178,992 178,992 Other comprehensive income — — — 21,305 — 21,305 Cash dividends ($0.485 per share) — — — — (54,054 ) (54,054 ) Common stock issued: Public and other stock offerings 76,776 — 6,235 — — 6,235 Stock-based compensation plans 21,440 — 5,248 — — 5,248 Balance, March 31, 2018 111,060,328 555 2,951,545 (85,011 ) 1,854,257 4,721,346 Net income — — — — 71,193 71,193 Other comprehensive income — — — 8,630 — 8,630 Cash dividends ($0.485 per share) — — — — (54,116 ) (54,116 ) Common stock issued: Public and other stock offerings 45,307 1 3,947 — — 3,948 Stock-based compensation plans 89,813 — 8,551 — — 8,551 Balance, June 30, 2018 111,195,448 $ 556 $ 2,964,043 $ (76,381 ) $ 1,871,334 $ 4,759,552
Schedule of Forward Sales Executed	The following table presents information relevant to the forward sales during fiscal year 2019. Maturity September 30, 2020 March 31, 2020 Total Shares Price (1) Proceeds Shares Price (1) Proceeds Shares Price (1) Proceeds (in millions) Available Balance September 30, 2018 — $ — $ — — $ — $ — — $ — $ — Issued via Block — — 2,668,464 91.77 2,668,464 91.77 Available Balance December 31, 2018 (2) — — — 2,668,464 91.90 245.2 2,668,464 91.90 245.2 Issued via ATM — — 1,670,509 95.46 1,670,509 95.46 Available Balance March 31, 2019 (2) — — — 4,338,973 93.08 403.9 4,338,973 93.08 403.9 Issued via ATM 1,050,563 101.41 — — 1,050,563 101.41 Settled Block — — (1,089,700 ) 91.44 (1,089,700 ) 91.44 Available Balance June 30, 2019 (2) 1,050,563 $ 101.11 $ 106.2 3,249,273 $ 93.34 $ 303.3 4,299,836 $ 95.24 $ 409.5 (1) Issued price as disclosed is calculated as the weighted average price for activity occurring during the quarter. (2) If we had settled all shares available under the forward agreements as of the period end, including forward price adjustments, we would receive proceeds based on the stated net price.
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- for-Sale Securities (1) Interest Rate Agreement Cash Flow Hedges Total (In thousands) September 30, 2018 $ 8,124 $ (91,771 ) $ (83,647 ) Other comprehensive income (loss) before reclassifications 192 (25,966 ) (25,774 ) Amounts reclassified from accumulated other comprehensive income (1 ) 1,969 1,968 Net current-period other comprehensive income (loss) 191 (23,997 ) (23,806 ) Cumulative effect of accounting change (See Note 2) (8,210 ) — (8,210 ) June 30, 2019 $ 105 $ (115,768 ) $ (115,663 ) Available- for-Sale Securities (1) Interest Rate Agreement Cash Flow Hedges Total (In thousands) September 30, 2017 $ 7,048 $ (112,302 ) $ (105,254 ) Other comprehensive income before reclassifications 148 28,315 28,463 Amounts reclassified from accumulated other comprehensive income (884 ) 1,294 410 Net current-period other comprehensive income (loss) (736 ) 29,609 28,873 June 30, 2018 $ 6,312 $ (82,693 ) $ (76,381 ) (1) Available-for-sale-securities reported in fiscal 2018 include both debt and equity securities, while fiscal 2019 includes only debt securities. See Note 2 for further discussion regarding our adoption of the new accounting standard.

Interim Pension and Other Pos_2

Interim Pension and Other Postretirement Benefit Plan Information (Table)	9 Months Ended
	Jun. 30, 2019
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 nine months ended June 30, 2019 and 2018 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 June 30 Pension Benefits Other Benefits 2019 2018 2019 2018 (In thousands) Components of net periodic pension cost: Service cost $ 4,044 $ 4,794 $ 2,702 $ 3,020 Interest cost (1) 6,799 6,448 2,960 2,726 Expected return on assets (1) (7,113 ) (6,917 ) (2,664 ) (2,002 ) Amortization of prior service cost (credit) (1) (57 ) (57 ) 43 2 Amortization of actuarial (gain) loss (1) 1,606 3,050 (2,045 ) (1,618 ) Settlements (1) — 888 — — Net periodic pension cost $ 5,279 $ 8,206 $ 996 $ 2,128 Nine Months Ended June 30 Pension Benefits Other Benefits 2019 2018 2019 2018 (In thousands) Components of net periodic pension cost: Service cost $ 12,134 $ 13,929 $ 8,107 $ 9,059 Interest cost (1) 20,399 19,311 8,879 8,180 Expected return on assets (1) (21,339 ) (20,750 ) (7,994 ) (6,005 ) Amortization of prior service cost (credit) (1) (173 ) (173 ) 130 8 Amortization of actuarial (gain) loss (1) 4,821 9,224 (6,134 ) (4,855 ) Settlements (1) — 3,303 — — Net periodic pension cost $ 15,842 $ 24,844 $ 2,988 $ 6,387 (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 statement of comprehensive income or are capitalized on the condensed consolidated balance sheets as a regulatory asset or liability, as described in Note 2.

Financial Instruments (Table)

Financial Instruments (Table)	9 Months Ended
	Jun. 30, 2019
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 June 30, 2019 and September 30, 2018 . 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, for June 30, 2019 and September 30, 2018 , no gross amounts and no cash collateral were netted within our consolidated balance sheet. Balance Sheet Location Assets Liabilities (In thousands) June 30, 2019 Not Designated As Hedges: Commodity contracts Other current assets / Other current liabilities $ 2,408 $ (3,358 ) Commodity contracts Deferred charges and other assets / Deferred credits and other liabilities 149 (513 ) Total 2,557 (3,871 ) Gross / Net Financial Instruments $ 2,557 $ (3,871 ) Balance Sheet Location Assets Liabilities (In thousands) September 30, 2018 Designated As Hedges: Interest rate swaps Other current assets / $ — $ (56,499 ) Total — (56,499 ) Not Designated As Hedges: Commodity contracts Other current assets / Other current liabilities 1,369 (235 ) Commodity contracts Deferred charges and other assets / Deferred credits and other liabilities 250 (103 ) Total 1,619 (338 ) Gross / Net Financial Instruments $ 1,619 $ (56,837 )
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 nine months ended June 30, 2019 and 2018 . 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 June 30 Nine Months Ended June 30 2019 2018 2019 2018 (In thousands) Increase (decrease) in fair value: Interest rate agreements $ — $ 7,861 $ (25,966 ) $ 28,315 Recognition of losses in earnings due to settlements: Interest rate agreements 1,053 459 1,969 1,294 Total other comprehensive income (loss) from hedging, net of tax $ 1,053 $ 8,320 $ (23,997 ) $ 29,609
Schedule Of Expected Deferred Gains (Losses) Recognition	The following amounts, net of deferred taxes, represent the expected recognition in earnings, as of June 30, 2019 , of the deferred losses recorded in AOCI associated with our financial instruments, based upon the fair values of these financial instruments at the date of settlement. Interest Rate Agreements (In thousands) Next twelve months $ (4,212 ) Thereafter (111,556 ) Total $ (115,768 )

Fair Value Measurements (Table)

Fair Value Measurements (Table)	9 Months Ended
	Jun. 30, 2019
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 June 30, 2019 and September 30, 2018 . Assets and liabilities are categorized in their entirety based on the lowest level of input that is significant to the fair value measurement. Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) (1) Significant Other Unobservable Inputs (Level 3) Netting and Cash Collateral June 30, 2019 (In thousands) Assets: Financial instruments $ — $ 2,557 $ — $ — $ 2,557 Debt and equity securities Registered investment companies 43,798 — — — 43,798 Bond mutual funds 25,778 — — — 25,778 Bonds (2) — 31,097 — — 31,097 Money market funds — 1,369 — — 1,369 Total debt and equity securities 69,576 32,466 — — 102,042 Total assets $ 69,576 $ 35,023 $ — $ — $ 104,599 Liabilities: Financial instruments $ — $ 3,871 $ — $ — $ 3,871 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) (1) Significant Other Unobservable Inputs (Level 3) Netting and Cash Collateral September 30, 2018 (In thousands) Assets: Financial instruments $ — $ 1,619 $ — $ — $ 1,619 Debt and equity securities Registered investment companies 42,644 — — — 42,644 Bond mutual funds 21,507 — — — 21,507 Bonds (2) — 31,400 — — 31,400 Money market funds — 3,834 — — 3,834 Total debt and equity securities 64,151 35,234 — — 99,385 Total assets $ 64,151 $ 36,853 $ — $ — $ 101,004 Liabilities: Financial instruments $ — $ 56,837 $ — $ — $ 56,837 (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 as described in Note 2.
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments	The following table presents the carrying value and fair value of our debt as of June 30, 2019 and September 30, 2018 : June 30, 2019 September 30, 2018 (In thousands) Carrying Amount $ 3,685,000 $ 3,085,000 Fair Value $ 4,144,253 $ 3,161,679

Nature of Business (Details)

Nature of Business (Details)	Jun. 30, 2019customerstateregulated_distribution_division
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of customers serviced | customer	3,000,000,000,000
Number of regulated distribution divisions | regulated_distribution_division	6
Number of states with service areas | state	8

Unaudited Financial Informati_4

Unaudited Financial Information (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Oct. 01, 2018	Sep. 30, 2018
Accounting Policies [Abstract]
Cummulative effect on accounting change, on equity or net assets		$ 8,200
Regulatory Asset [Line Items]
Regulatory assets	$ 164,670		$ 143,811
Regulatory Liabilities [Line Items]
Regulatory liabilities	1,489,875		1,510,997
Regulatory excess deferred taxes
Regulatory Liabilities [Line Items]
Regulatory liabilities	731,837		744,895
Regulatory cost of service reserve
Regulatory Liabilities [Line Items]
Regulatory liabilities	6,079		22,508
Regulatory cost of removal obligation
Regulatory Liabilities [Line Items]
Regulatory liabilities	526,403		522,175
Deferred gas costs
Regulatory Liabilities [Line Items]
Regulatory liabilities	66,171		94,705
Asset retirement obligation
Regulatory Liabilities [Line Items]
Regulatory liabilities	12,887		12,887
Other
Regulatory Liabilities [Line Items]
Regulatory liabilities	3,038		9,486
APT annual adjustment mechanism
Regulatory Liabilities [Line Items]
Regulatory liabilities	63,130		35,228
Pension and other postreitrement plans costs
Regulatory Liabilities [Line Items]
Regulatory liabilities	80,330		69,113
Pension and other postreitrement plans costs
Regulatory Asset [Line Items]
Regulatory assets	8,007		6,496
Infrastructure mechanisms
Regulatory Asset [Line Items]
Regulatory assets	111,211		96,739
Deferred gas costs
Regulatory Asset [Line Items]
Regulatory assets	7,227		1,927
Recoverable loss on reacquired debt
Regulatory Asset [Line Items]
Regulatory assets	7,000		8,702
Deferred pipeline record collection costs
Regulatory Asset [Line Items]
Regulatory assets	25,347		20,467
Rate case costs
Regulatory Asset [Line Items]
Regulatory assets	1,413		2,741
Other
Regulatory Asset [Line Items]
Regulatory assets	4,465		6,739
Other Current Liabilities | Regulatory excess deferred taxes
Regulatory Liabilities [Line Items]
Regulatory liabilities	$ 21,900		$ 5,200

Segment Information (Details)

Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2018
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	$ 485,738			$ 562,245			$ 2,458,165	$ 2,670,846
Cost of Revenue	31,326			130,886			845,167	1,124,763
Operation and maintenance expense	164,545			143,748			452,572	431,952
Depreciation and amortization expense	97,700			90,671			290,537	268,426
Taxes, other than income	69,965			72,620			213,546	208,400
Operating income	122,202			124,320			656,343	637,305
Other non-operating income (expense)	1,645			(3,330)			(1,846)	(8,054)
Interest charges	19,592			23,349			74,390	82,162
Income before income taxes	104,255			97,641			580,107	547,089
Income tax (benefit) expense	23,789			26,448			127,107	(17,228)
Net income	80,466	$ 214,888	$ 157,646	71,193	$ 178,992	$ 314,132	453,000	564,317
Capital expenditures	421,613			394,494			1,199,199	1,088,472
Segment Reporting Information, Balance Sheet [Abstract]
Property, plant and equipment, net	11,340,596						11,340,596		$ 10,371,147
Total assets	12,881,098						12,881,098		11,874,437
Operating Segments | Distribution
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	444,944			535,488			2,341,668	2,595,571
Operation and maintenance expense	123,998			110,568			347,386	343,860
Depreciation and amortization expense	70,611			66,504			210,224	197,587
Taxes, other than income	62,134			64,420			189,377	184,219
Operating income	48,683			63,109			447,083	448,207
Other non-operating income (expense)	3,005			(2,518)			1,791	(5,961)
Interest charges	10,597			13,315			44,703	51,581
Income before income taxes	41,091			47,276			404,171	390,665
Income tax (benefit) expense	8,693			11,932			85,195	(39,021)
Net income	32,398			35,344			318,976	429,686
Capital expenditures	316,825			284,209			912,640	749,693
Segment Reporting Information, Balance Sheet [Abstract]
Property, plant and equipment, net	8,404,238						8,404,238		7,644,693
Total assets	12,083,315						12,083,315		11,109,128
Operating Segments | Pipeline and Storage
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	149,198			127,633			419,318	375,051
Operation and maintenance expense	40,855			33,494			106,120	89,027
Depreciation and amortization expense	27,089			24,167			80,313	70,839
Taxes, other than income	7,831			8,200			24,169	24,181
Operating income	73,519			61,211			209,260	189,098
Other non-operating income (expense)	(1,360)			(812)			(3,637)	(2,093)
Interest charges	8,995			10,034			29,687	30,581
Income before income taxes	63,164			50,365			175,936	156,424
Income tax (benefit) expense	15,096			14,516			41,912	21,793
Net income	48,068			35,849			134,024	134,631
Capital expenditures	104,788			110,285			286,559	338,779
Segment Reporting Information, Balance Sheet [Abstract]
Property, plant and equipment, net	2,936,358						2,936,358		2,726,454
Total assets	3,174,516						3,174,516		2,963,480
Intersegment eliminations
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	(108,404)			(100,876)			(302,821)	(299,776)
Operation and maintenance expense	(308)			(314)			(934)	(935)
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 (expense)	0			0			0	0
Interest charges	0			0			0	0
Income before income taxes	0			0			0	0
Income tax (benefit) expense	0			0			0	0
Net income	0			0			0	0
Capital expenditures	0			0			0	0
Intersegment eliminations | Intersegment eliminations
Segment Reporting Information, Balance Sheet [Abstract]
Property, plant and equipment, net	0						0		0
Total assets	(2,376,733)						(2,376,733)		$ (2,198,171)
Reportable Subsegments
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	485,738			562,245			2,458,165	2,670,846
Reportable Subsegments | Distribution
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	444,287			534,816			2,339,660	2,593,578
Reportable Subsegments | Pipeline and Storage
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	41,451			27,429			118,505	77,268
Reportable Subsegments | Intersegment eliminations
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	0			0			0	0
Intersubsegment Eliminations
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	0			0			0	0
Intersubsegment Eliminations | Distribution
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	657			672			2,008	1,993
Intersubsegment Eliminations | Pipeline and Storage
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	107,747			100,204			300,813	297,783
Intersubsegment Eliminations | Intersegment eliminations
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	(108,404)			(100,876)			(302,821)	(299,776)
Natural Gas, US Regulated
Segment Reporting Information Profit Loss [Abstract]
Cost of Revenue	31,326			130,886			845,167	1,124,763
Natural Gas, US Regulated | Operating Segments | Distribution
Segment Reporting Information Profit Loss [Abstract]
Cost of Revenue	139,518			230,887			1,147,598	1,421,698
Natural Gas, US Regulated | Operating Segments | Pipeline and Storage
Segment Reporting Information Profit Loss [Abstract]
Cost of Revenue	(96)			561			(544)	1,906
Natural Gas, US Regulated | Intersegment eliminations
Segment Reporting Information Profit Loss [Abstract]
Cost of Revenue	$ (108,096)			$ (100,562)			$ (301,887)	$ (298,841)

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2019	Jun. 30, 2018
Basic and Diluted Earnings Per Share, Continuing Operations [Abstract]
Net income	$ 80,466	$ 214,888	$ 157,646	$ 71,193	$ 178,992	$ 314,132	$ 453,000	$ 564,317
Income allocated to participating securities	64			59			386	545
Income available to common shareholders	$ 80,402			$ 71,134			$ 452,614	$ 563,772
Basic weighted average shares outstanding	118,075			111,851			116,485	110,707
Basic net income per share	$ 0.68			$ 0.64			$ 3.89	$ 5.09
Effect of dilutive shares	$ 0			$ 0			$ 0	$ 0
Income available to common shareholders	$ 80,402			$ 71,134			$ 452,614	$ 563,772
Additional dilutive shares	355			0			188	0
Diluted weighted average shares outstanding	118,430			111,851			116,673	110,707
Diluted net income per share	$ 0.68			$ 0.64			$ 3.88	$ 5.09

Revenue (Details)

Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 485,738	$ 562,245	$ 2,458,165	$ 2,670,846
Distribution segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	443,705		2,353,535
Alternative Revenue Program Revenues	748		(13,388)
Other Revenues	491		1,521
Pipeline and storage segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	169,271		463,420
Alternative Revenue Program Revenues	(20,073)		(44,102)
Other Revenues	0		0
Gas sales revenue [Member] | Distribution segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	414,657		2,257,091
Gas sales revenue [Member] | Pipeline and storage segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	0		0
Gas sales revenue [Member] | Residential Customers [Member] | Distribution segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	269,484		1,513,239
Gas sales revenue [Member] | Residential Customers [Member] | Pipeline and storage segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	0		0
Gas sales revenue [Member] | Commercial Customers [Member] | Distribution segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	113,591		611,474
Gas sales revenue [Member] | Commercial Customers [Member] | Pipeline and storage segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	0		0
Gas sales revenue [Member] | Industrial Customers [Member] | Distribution segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	25,277		95,701
Gas sales revenue [Member] | Industrial Customers [Member] | Pipeline and storage segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	0		0
Gas sales revenue [Member] | Public Authority and Other Customers [Member] | Distribution segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	6,305		36,677
Gas sales revenue [Member] | Public Authority and Other Customers [Member] | Pipeline and storage segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	0		0
Transportation revenue [Member] | Distribution segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	22,923		76,005
Transportation revenue [Member] | Pipeline and storage segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	166,864		456,558
Miscellaneous revenue [Member] | Distribution segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	6,125		20,439
Miscellaneous revenue [Member] | Pipeline and storage segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	2,407		6,862
Operating Segments | Distribution segment
Disaggregation of Revenue [Line Items]
Total operating revenues	444,944	535,488	2,341,668	2,595,571
Operating Segments | Pipeline and storage segment
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 149,198	$ 127,633	$ 419,318	$ 375,051

Revenue Narrative (Details)

Revenue Narrative (Details) $ in Millions	9 Months Ended
	Jun. 30, 2019USD ($)
Alternative Revenue Program [Line Items]
Rate Case Revenue Benchmark	$ 69.4
Regulatory Mechanism Threshold	75.00%

Debt - Schedule of Long-term De

Debt - Schedule of Long-term Debt Instruments (Details) - USD ($)	Jun. 30, 2019	Mar. 04, 2019	Oct. 04, 2018	Sep. 30, 2018
Debt Instrument [Line Items]
Total long-term debt	$ 3,685,000,000			$ 3,085,000,000
Original issue (premium) / discount on unsecured senior notes and debentures	225,000			(4,439,000)
Debt issuance cost	30,640,000			20,774,000
Current maturities	125,000,000			575,000,000
Long-term debt	3,529,135,000			2,493,665,000
Unsecured 8.50% Senior Notes, due March 2019
Debt Instrument [Line Items]
Total long-term debt	0			$ 450,000,000
Interest rate				8.50%
Unsecured 3.00% Senior Notes, due 2027
Debt Instrument [Line Items]
Total long-term debt	$ 500,000,000			$ 500,000,000
Interest rate	3.00%			3.00%
Unsecured 5.95% Senior Notes, due 2034
Debt Instrument [Line Items]
Total long-term debt	$ 200,000,000			$ 200,000,000
Interest rate	5.95%			5.95%
Unsecured 5.50% Senior Notes, due 2041
Debt Instrument [Line Items]
Total long-term debt	$ 400,000,000			$ 400,000,000
Interest rate	5.50%			5.50%
Unsecured 4.15% Senior Notes, due 2043
Debt Instrument [Line Items]
Total long-term debt	$ 500,000,000			$ 500,000,000
Interest rate	4.15%			4.15%
Unsecured 4.125% Senior Notes, due 2044
Debt Instrument [Line Items]
Total long-term debt	$ 750,000,000			$ 750,000,000
Interest rate	4.125%			4.125%
Medium-term note Series A, 1995-1, 6.67%, due 2025
Debt Instrument [Line Items]
Total long-term debt	$ 10,000,000			$ 10,000,000
Interest rate	6.67%			6.67%
Unsecured 6.75% Debentures, due 2028
Debt Instrument [Line Items]
Total long-term debt	$ 150,000,000			$ 150,000,000
Interest rate	6.75%			6.75%
Floating-rate term loan, due September 2019
Debt Instrument [Line Items]
Total long-term debt	$ 125,000,000			$ 125,000,000
Maximum borrowing capacity	200,000,000			200,000,000
Unsecured 4.30% Senior Notes, due 2048
Debt Instrument [Line Items]
Total long-term debt	$ 600,000,000		$ 600,000,000	0
Interest rate	4.30%		4.30%
Unsecured 4.125% Senior Notes, due 2049
Debt Instrument [Line Items]
Total long-term debt	$ 450,000,000	$ 450,000,000		$ 0
Interest rate	4.125%	4.125%

Debt - Narrative (Details)

Debt - Narrative (Details) - USD ($)	Mar. 04, 2019	Oct. 04, 2018	Jun. 30, 2019	Sep. 30, 2018
Line Of Credit Facility [Line Items]
Total long-term debt			$ 3,685,000,000	$ 3,085,000,000
Maximum borrowing capacity			$ 1,500,000,000
Maximum debt-to-total-capitalization ratio			70.00%
Debt-to-total-capitalization ratio			0.41
Minimum
Line Of Credit Facility [Line Items]
Equity-to-total-capitalization ratio			50.00%
Outstanding indebtedness			$ 15,000,000
Maximum
Line Of Credit Facility [Line Items]
Equity-to-total-capitalization ratio			60.00%
Outstanding indebtedness			$ 100,000,000
Five Year Unsecured Revolving Credit Agreement
Line Of Credit Facility [Line Items]
Outstanding commercial paper			74,900,000	575,800,000
Five Year Unsecured Revolving Credit Agreement | Commercial Paper
Line Of Credit Facility [Line Items]
Maximum borrowing capacity			1,500,000,000
Accordion feature			250,000,000
Maximum borrowing capacity post accordion feature			1,750,000,000
$25 Million Bank Loan Agreement | Line of Credit
Line Of Credit Facility [Line Items]
Maximum borrowing capacity			25,000,000
Outstanding borrowings			0
$10 Million Revolving Credit Note | Revolving Credit Facility
Line Of Credit Facility [Line Items]
Maximum borrowing capacity			10,000,000
Remaining borrowing capacity			4,400,000
Unsecured 4.30% Senior Notes, due 2048
Line Of Credit Facility [Line Items]
Total long-term debt		$ 600,000,000	$ 600,000,000	0
Interest rate		4.30%	4.30%
Proceeds from Issuance of Debt		$ 590,600,000
Effective interest rate		4.37%
Unsecured 4.125% Senior Notes, due 2049
Line Of Credit Facility [Line Items]
Total long-term debt	$ 450,000,000		$ 450,000,000	0
Interest rate	4.125%		4.125%
Proceeds from Issuance of Debt	$ 443,400,000
Effective interest rate	4.86%
Unsecured 8.50% Senior Notes, due March 2019
Line Of Credit Facility [Line Items]
Total long-term debt			$ 0	$ 450,000,000
Interest rate				8.50%
LIBOR | Five Year Unsecured Revolving Credit Agreement | Commercial Paper | Minimum
Line Of Credit Facility [Line Items]
Interest rate spread			0.00%
LIBOR | Five Year Unsecured Revolving Credit Agreement | Commercial Paper | Maximum
Line Of Credit Facility [Line Items]
Interest rate spread			1.25%

Shareholders' Equity Statement

Shareholders' Equity Statement of Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2019	Jun. 30, 2018	Oct. 01, 2018	Sep. 30, 2018	Sep. 30, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock outstanding (in shares)	118,196,113						118,196,113			111,273,683
Shareholders' equity, beginning balance	$ 5,508,101	$ 5,348,195	$ 4,769,951	$ 4,721,346	$ 4,563,620	$ 3,898,666	$ 4,769,951	$ 3,898,666
Net income	80,466	214,888	157,646	71,193	178,992	314,132	453,000	564,317
Other Comprehensive Loss, Net of Tax	1,147	(2,695)	(22,258)	8,630	21,305	(1,062)
Cash dividends	(61,654)	(61,606)	(58,722)	(54,116)	(54,054)	(51,837)
Stock Issued or Granted During Period, Share-based Compensation [Abstract]
Public and other stock offerings	103,430	5,454	498,975	3,948	6,235	400,759
Stock-based compensation plans	10,506	3,865	2,603	8,551	5,248	2,962
Shareholders' equity, ending balance	$ 5,641,996	$ 5,508,101	$ 5,348,195	$ 4,759,552	$ 4,721,346	$ 4,563,620	$ 5,641,996	$ 4,759,552
Cash dividends per share	$ 0.525	$ 0.525	$ 0.525	$ 0.485	$ 0.485	$ 0.485	$ 1.575	$ 1.455
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock outstanding (in shares)	118,196,113	116,982,903	116,892,959	111,195,448	111,060,328	110,962,112	118,196,113	111,195,448		111,273,683	106,104,634
Shareholders' equity, beginning balance	$ 585	$ 584	$ 556	$ 555	$ 555	$ 531	$ 556	$ 531
Stock Issued or Granted During Period, Share-based Compensation [Abstract]
Public and other stock offerings (in shares)	1,127,244	61,006	5,434,812	45,307	76,776	4,621,518
Public and other stock offerings	$ 5	$ 1	$ 27	$ 1	$ 0	$ 22
Stock-based compensation plans (in shares)	85,966	28,938	184,464	89,813	21,440	235,960
Stock-based compensation plans	$ 1	$ 0	$ 1	$ 0	$ 0	$ 2
Shareholders' equity, ending balance	591	585	584	556	555	555	591	556
Additional Paid-in Capital [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shareholders' equity, beginning balance	3,485,794	3,476,476	2,974,926	2,951,545	2,940,062	2,536,365	2,974,926	2,536,365
Stock Issued or Granted During Period, Share-based Compensation [Abstract]
Public and other stock offerings	103,425	5,453	498,948	3,947	6,235	400,737
Stock-based compensation plans	10,505	3,865	2,602	8,551	5,248	2,960
Shareholders' equity, ending balance	3,599,724	3,485,794	3,476,476	2,964,043	2,951,545	2,940,062	3,599,724	2,964,043
Accumulated Other Comprehensive Income
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shareholders' equity, beginning balance	(116,810)	(114,115)	(83,647)	(85,011)	(106,316)	(105,254)	(83,647)	(105,254)
Other Comprehensive Loss, Net of Tax	1,147	(2,695)	(22,258)	8,630	21,305	(1,062)	(23,806)	28,873
Cumulative Effect of New Accounting Principle in Period of Adoption									$ (8,210)
Stock Issued or Granted During Period, Share-based Compensation [Abstract]
Shareholders' equity, ending balance	(115,663)	(116,810)	(114,115)	(76,381)	(85,011)	(106,316)	(115,663)	(76,381)
Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shareholders' equity, beginning balance	2,138,532	1,985,250	1,878,116	1,854,257	1,729,319	1,467,024	1,878,116	1,467,024
Net income	80,466	214,888	157,646	71,193	178,992	314,132
Cash dividends	(61,654)	(61,606)	(58,722)	(54,116)	(54,054)	(51,837)
Cumulative Effect of New Accounting Principle in Period of Adoption									$ 8,210
Stock Issued or Granted During Period, Share-based Compensation [Abstract]
Shareholders' equity, ending balance	$ 2,157,344	$ 2,138,532	$ 1,985,250	$ 1,871,334	$ 1,854,257	$ 1,729,319	$ 2,157,344	$ 1,871,334

Shareholders' Equity Schedule o

Shareholders' Equity Schedule of Forward Sales Executed (Details) - USD ($) $ / shares in Units, $ in Millions	May 28, 2019	May 24, 2019	Feb. 19, 2019	Nov. 30, 2018	Nov. 30, 2017	Dec. 31, 2018	Mar. 31, 2019	Jun. 30, 2019	Sep. 30, 2018
Forward Contract Indexed to Issuer's Equity [Line Items]
Forward sales equity agreement, forward rate per share						$ 91.90	$ 93.08	$ 95.24	$ 0
Forward sales equity agreement, settlement in cash						$ 245.2	$ 403.9	$ 409.5	$ 0
Forward sales equity agreement, settlement in shares						2,668,464	4,338,973	4,299,836	0
At-The-Market
Forward Contract Indexed to Issuer's Equity [Line Items]
Forward sales equity agreement, shares		1,050,563	1,670,509
Forward sales equity agreement, forward rate per share		$ 101.41	$ 95.46
Common Stock Block Trade
Forward Contract Indexed to Issuer's Equity [Line Items]
Forward sales equity agreement, shares				2,668,464
Forward sales equity agreement, forward rate per share				$ 91.77
Stock Issued During Period, New Issues (in shares)	1,089,700			5,390,836	4,558,404
Stock Issued During Period, New Issues (Per Share)	$ 91.44
Forward Sales Equity, Maturity September 2020
Forward Contract Indexed to Issuer's Equity [Line Items]
Forward sales equity agreement, forward rate per share						$ 0	$ 0	$ 101.11	$ 0
Forward sales equity agreement, settlement date								Sep. 30, 2020
Forward sales equity agreement, settlement in cash						$ 0	$ 0	$ 106.2	$ 0
Forward sales equity agreement, settlement in shares						0	0	1,050,563	0
Forward Sales Equity, Maturity September 2020 | At-The-Market
Forward Contract Indexed to Issuer's Equity [Line Items]
Forward sales equity agreement, shares		1,050,563	0
Forward sales equity agreement, forward rate per share		$ 101.41	$ 0
Forward Sales Equity, Maturity September 2020 | Common Stock Block Trade
Forward Contract Indexed to Issuer's Equity [Line Items]
Forward sales equity agreement, shares				0
Forward sales equity agreement, forward rate per share				$ 0
Stock Issued During Period, New Issues (in shares)	0
Stock Issued During Period, New Issues (Per Share)	$ 0
Forward Sales Equity, Maturity March 2020
Forward Contract Indexed to Issuer's Equity [Line Items]
Forward sales equity agreement, forward rate per share						$ 91.90	$ 93.08	$ 93.34	$ 0
Forward sales equity agreement, settlement date								Mar. 31, 2020
Forward sales equity agreement, settlement in cash						$ 245.2	$ 403.9	$ 303.3	$ 0
Forward sales equity agreement, settlement in shares						2,668,464	4,338,973	3,249,273	0
Forward Sales Equity, Maturity March 2020 | At-The-Market
Forward Contract Indexed to Issuer's Equity [Line Items]
Forward sales equity agreement, shares		0	1,670,509
Forward sales equity agreement, forward rate per share		$ 0	$ 95.46
Forward Sales Equity, Maturity March 2020 | Common Stock Block Trade
Forward Contract Indexed to Issuer's Equity [Line Items]
Forward sales equity agreement, shares				2,668,464
Forward sales equity agreement, forward rate per share				$ 91.77
Stock Issued During Period, New Issues (in shares)	1,089,700
Stock Issued During Period, New Issues (Per Share)	$ 91.44

Shareholders' Equity Schedule_2

Shareholders' Equity Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2019	Jun. 30, 2018	Oct. 01, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Shareholders' equity, beginning balance	$ 5,508,101	$ 5,348,195	$ 4,769,951	$ 4,721,346	$ 4,563,620	$ 3,898,666	$ 4,769,951	$ 3,898,666
Net current-period other comprehensive income (loss)	1,147	(2,695)	(22,258)	8,630	21,305	(1,062)
Cummulative effect on accounting change, on equity or net assets									$ 8,200
Shareholders' equity, ending balance	5,641,996	5,508,101	5,348,195	4,759,552	4,721,346	4,563,620	5,641,996	4,759,552
Available- for-Sale Securities(1)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Shareholders' equity, beginning balance			8,124			7,048	8,124	7,048
Other comprehensive income (loss) before reclassifications							192	148
Amounts reclassified from accumulated other comprehensive income							(1)	(884)
Net current-period other comprehensive income (loss)							191	(736)
Cummulative effect on accounting change, on equity or net assets									(8,210)
Shareholders' equity, ending balance	105			6,312			105	6,312
Cash Flow Hedges | Interest rate agreements
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Shareholders' equity, beginning balance			(91,771)			(112,302)	(91,771)	(112,302)
Other comprehensive income (loss) before reclassifications							(25,966)	28,315
Amounts reclassified from accumulated other comprehensive income							1,969	1,294
Net current-period other comprehensive income (loss)							(23,997)	29,609
Cummulative effect on accounting change, on equity or net assets									0
Shareholders' equity, ending balance	(115,768)			(82,693)			(115,768)	(82,693)
Accumulated Other Comprehensive Income
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Shareholders' equity, beginning balance	(116,810)	(114,115)	(83,647)	(85,011)	(106,316)	(105,254)	(83,647)	(105,254)
Other comprehensive income (loss) before reclassifications							(25,774)	28,463
Amounts reclassified from accumulated other comprehensive income							1,968	410
Net current-period other comprehensive income (loss)	1,147	(2,695)	(22,258)	8,630	21,305	(1,062)	(23,806)	28,873
Cummulative effect on accounting change, on equity or net assets									$ (8,210)
Shareholders' equity, ending balance	$ (115,663)	$ (116,810)	$ (114,115)	$ (76,381)	$ (85,011)	$ (106,316)	$ (115,663)	$ (76,381)

Shareholders' Equity Narrative

Shareholders' Equity Narrative (Details) - USD ($)	May 28, 2019	Nov. 30, 2018	Nov. 30, 2017	Jun. 30, 2019	Jun. 30, 2018	Nov. 19, 2018	Nov. 13, 2018
Class of Stock [Line Items]
Net proceeds from equity offering				$ 593,731,000	$ 395,092,000
Shelf Registration Statement
Class of Stock [Line Items]
Debt and equity securities authorized for issuance							$ 3,000,000,000
Debt and equity securities authorized for issuance value remaining				1,300,000,000
At-The-Market
Class of Stock [Line Items]
Value of shares authorized for issuance						$ 500,000,000
Value of shares available for issuance				$ 231,000,000
Common Stock Block Trade
Class of Stock [Line Items]
Stock Issued During Period, New Issues (in shares)	1,089,700	5,390,836	4,558,404
Gross proceeds from equity offering		$ 500,000,000	$ 400,000,000
Net proceeds from equity offering		$ 494,100,000	$ 395,100,000

Interim Pension and Other Pos_3

Interim Pension and Other Postretirement Benefit Plan Information - Schedule of Net Benefit Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4,044	$ 4,794	$ 12,134	$ 13,929
Interest cost	6,799	6,448	20,399	19,311
Expected return on assets	(7,113)	(6,917)	(21,339)	(20,750)
Amortization of prior service cost (credit)	(57)	(57)	(173)	(173)
Amortization of actuarial (gain) loss	1,606	3,050	4,821	9,224
Settlements	0	(888)	0	(3,303)
Net periodic pension cost	5,279	8,206	15,842	24,844
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	2,702	3,020	8,107	9,059
Interest cost	2,960	2,726	8,879	8,180
Expected return on assets	(2,664)	(2,002)	(7,994)	(6,005)
Amortization of prior service cost (credit)	43	2	130	8
Amortization of actuarial (gain) loss	(2,045)	(1,618)	(6,134)	(4,855)
Settlements	0	0	0	0
Net periodic pension cost	$ 996	$ 2,128	$ 2,988	$ 6,387

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Millions	9 Months Ended
	Jun. 30, 2019USD ($)Bcf
Loss Contingencies [Line Items]
Self-insurance retention expense | $	$ 1
Operating Leased Assets [Line Items]
Operating leases, future minimum payments due | $	$ 194.9
Minimum
Operating Leased Assets [Line Items]
Lease term of contract	1 year
Maximum
Operating Leased Assets [Line Items]
Lease term of contract	20 years
Long-term Contract with Customer | Supply Commitment
Long-term Purchase Commitment [Line Items]
Long-term Purchase Commitment, Minimum Volume Required | Bcf	1,800
Short-term Contract with Customer | Supply Commitment
Long-term Purchase Commitment [Line Items]
Long-term Purchase Commitment, Minimum Volume Required | Bcf	53,900

Financial Instruments - Narrati

Financial Instruments - Narrative (Details)	3 Months Ended		9 Months Ended
	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)BcfMMcf	Jun. 30, 2018USD ($)	Sep. 30, 2018USD ($)
Derivative [Line Items]
Net realized gain (loss) in AOCI	$ (115,800,000)		$ (115,800,000)
Net gain (loss) on settled interest rate agreements	(1,400,000)	$ (600,000)	2,600,000	$ 1,800,000
Total long-term debt	3,685,000,000		3,685,000,000		$ 3,085,000,000
Unsecured 8.50% Senior Notes, due March 2019
Derivative [Line Items]
Total long-term debt	$ 0		$ 0		$ 450,000,000
Gas Purchases | Not Designated as Hedging Instrument | Commodity contracts
Derivative [Line Items]
Hedging percent	33.00%		33.00%
Energy measure | Bcf			18,900
Minimum | Gas Purchases | Not Designated as Hedging Instrument | Commodity contracts
Derivative [Line Items]
Hedging percent	25.00%		25.00%
Maximum | Gas Purchases | Not Designated as Hedging Instrument | Commodity contracts
Derivative [Line Items]
Hedging percent	50.00%		50.00%
Cash Flow Hedging | Designated as Hedging Instrument | Interest Rate Swap
Derivative [Line Items]
Notional amount	$ 450,000,000		$ 450,000,000
Net gain (loss) on settled interest rate agreements			90,100,000
Cash Flow Hedging | Designated as Hedging Instrument | Interest Rate Swap | Unsecured 8.50% Senior Notes, due March 2019
Derivative [Line Items]
Total long-term debt	$ 450,000,000		$ 450,000,000
Long | Gas Purchases | Not Designated as Hedging Instrument | Commodity contracts
Derivative [Line Items]
Energy measure | MMcf			16,784

Financial Instruments - Schedul

Financial Instruments - Schedule of Derivative Instruments in Statement of Financial Position, Fair Value (Details) - USD ($)	Jun. 30, 2019	Sep. 30, 2018
Derivatives Fair Value [Line Items]
Contract Netting	$ 0	$ 0
Net Financial Instruments, Assets	2,557,000	1,619,000
Cash collateral	0
Net Financial Instruments, Liabilities	(3,871,000)	(56,837,000)
Designated as Hedging Instrument
Derivatives Fair Value [Line Items]
Gross Financial Instruments, Assets		0
Gross Financial Instruments, Liabilities		(56,499,000)
Designated as Hedging Instrument | Other Current Assets | Interest rate agreements
Derivatives Fair Value [Line Items]
Gross Financial Instruments, Assets		0
Designated as Hedging Instrument | Other Current Liabilities | Interest rate agreements
Derivatives Fair Value [Line Items]
Gross Financial Instruments, Liabilities		(56,499,000)
Not Designated as Hedging Instrument
Derivatives Fair Value [Line Items]
Gross Financial Instruments, Assets	2,557,000	1,619,000
Gross Financial Instruments, Liabilities	(3,871,000)	(338,000)
Not Designated as Hedging Instrument | Other Current Assets | Commodity contracts
Derivatives Fair Value [Line Items]
Gross Financial Instruments, Assets	2,408,000	1,369,000
Not Designated as Hedging Instrument | Other Current Liabilities | Commodity contracts
Derivatives Fair Value [Line Items]
Gross Financial Instruments, Liabilities	(3,358,000)	(235,000)
Not Designated as Hedging Instrument | Deferred Charges and Other Assets | Commodity contracts
Derivatives Fair Value [Line Items]
Gross Financial Instruments, Assets	149,000	250,000
Not Designated as Hedging Instrument | Deferred Credits and Other Liabilities | Commodity contracts
Derivatives Fair Value [Line Items]
Gross Financial Instruments, Liabilities	$ (513,000)	$ (103,000)

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		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Increase (decrease) in fair value:
Interest rate agreements	$ 0	$ 7,861	$ (25,966)	$ 28,315
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Interest rate agreements	1,053	459	1,969	1,294
Total other comprehensive income (loss) from hedging, net of tax	$ 1,053	$ 8,320	$ (23,997)	$ 29,609

Financial Instruments - Sched_3

Financial Instruments - Schedule Of Expected Deferred Gains (Losses) Recognition (Details) $ in Thousands	Jun. 30, 2019USD ($)
Derivative [Line Items]
Interest Rate Agreements	$ (115,768)
Next twelve months
Derivative [Line Items]
Interest Rate Agreements	(4,212)
Thereafter
Derivative [Line Items]
Interest Rate Agreements	$ (111,556)

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($)	Jun. 30, 2019	Sep. 30, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Netting and Cash Collateral	$ 0	$ 0
Financial instruments net assets	2,557,000	1,619,000
Debt and equity securities	102,042,000	99,385,000
Total assets	104,599,000	101,004,000
Netting and Cash Collateral	0	0
Financial instruments net liability	3,871,000	56,837,000
Registered investment companies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity Securities	43,798,000	42,644,000
Bond mutual funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity Securities	25,778,000	21,507,000
Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	31,097,000	31,400,000
Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity Securities	1,369,000	3,834,000
Fair Value Inputs 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	69,576,000	64,151,000
Total assets	69,576,000	64,151,000
Financial instruments gross liability	0	0
Fair Value Inputs Level 1 | Registered investment companies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity Securities	43,798,000	42,644,000
Fair Value Inputs Level 1 | Bond mutual funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity Securities	25,778,000	21,507,000
Fair Value Inputs Level 1 | Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0	0
Fair Value Inputs Level 1 | Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity Securities	0	0
Fair Value Inputs Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial instruments gross assets	2,557,000	1,619,000
Debt and equity securities	32,466,000	35,234,000
Total assets	35,023,000	36,853,000
Financial instruments gross liability	3,871,000	56,837,000
Fair Value Inputs Level 2 | Registered investment companies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity Securities	0	0
Fair Value Inputs Level 2 | Bond mutual funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity Securities	0	0
Fair Value Inputs Level 2 | Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	31,097,000	31,400,000
Fair Value Inputs Level 2 | Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity Securities	1,369,000	3,834,000
Fair Value 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
Fair Value Inputs Level 3 | Registered investment companies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity Securities	0	0
Fair Value Inputs Level 3 | Bond mutual funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity Securities	0	0
Fair Value Inputs Level 3 | Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0	0
Fair Value 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 Narrati

Fair Value Measurements Narrative (Details) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Bonds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 31	$ 31.5

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Carrying Values and Estimated Fair Values of Debt Instruments (Details) - USD ($)	Jun. 30, 2019	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Total long-term debt	$ 3,685,000,000	$ 3,085,000,000
Long-term Debt, Fair Value	$ 4,144,253,000	$ 3,161,679,000

Impact of the Tax Cuts and Jo_2

Impact of the Tax Cuts and Jobs Act of 2017 (Details) - USD ($) $ in Millions	9 Months Ended
	Jun. 30, 2019	Sep. 30, 2018
Income Tax Examination [Line Items]
TCJA Income Tax Benefit	$ 165.5
Regulated operations recorded as a regulatory liability	731.8	$ 744.9
TCJA additional regulatory liability due to tax rates used in rates	$ 6.1	$ 22.5
Minimum
Income Tax Examination [Line Items]
Return issuance period	13 years
Maximum
Income Tax Examination [Line Items]
Return issuance period	51 years