Atmos Energy (ATO) 10-Q 5 Feb 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Dec. 31, 2018	Jan. 30, 2019
Document And Entity Information [Abstract]
Entity Registrant Name	Atmos Energy Corporation
Entity Central Index Key	731,802
Current Fiscal Year End Date	--09-30
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,019
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		116,897,373
Entity Small Business	false
Entity Emerging Growth Company	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Sep. 30, 2018
ASSETS
Property, plant and equipment	$ 12,948,229	$ 12,567,373
Less accumulated depreciation and amortization	2,250,000	2,196,226
Net property, plant and equipment	10,698,229	10,371,147
Current assets
Cash and cash equivalents	218,197	13,771
Accounts receivable, net	478,373	253,295
Gas stored underground	146,552	165,732
Other current assets	69,616	46,055
Total current assets	912,738	478,853
Goodwill	730,419	730,419
Deferred charges and other assets	274,403	294,018
Total assets	12,615,789	11,874,437
Shareholders’ equity
Common stock, no par value (stated at $0.005 per share); 200,000,000 shares authorized; issued and outstanding: December 31, 2018 — 116,892,959 shares; September 30, 2018 — 111,273,683 shares	584	556
Additional paid-in capital	3,476,476	2,974,926
Accumulated other comprehensive loss	(114,115)	(83,647)
Retained earnings	1,985,250	1,878,116
Shareholders’ equity	5,348,195	4,769,951
Long-term debt	3,084,779	2,493,665
Total capitalization	8,432,974	7,263,616
Current liabilities
Accounts payable and accrued liabilities	301,734	217,283
Other current liabilities	578,764	547,068
Short-term debt	0	575,780
Current maturities of long-term debt	575,000	575,000
Total current liabilities	1,455,498	1,915,131
Deferred income taxes	1,191,824	1,154,067
Regulatory excess deferred taxes (See Note 13)	717,758	739,670
Regulatory Cost Of Removal Liability Noncurrent	468,825	466,405
Pension and postretirement liabilities	176,582	177,520
Deferred credits and other liabilities	172,328	158,028
Total shareholders' equity and liabilities	$ 12,615,789	$ 11,874,437

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (PARENTHETICAL) - $ / shares	Dec. 31, 2018	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)	116,892,959	111,273,683
Common stock outstanding (in shares)	116,892,959	111,273,683

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Operating revenues
Total operating revenues	$ 877,782	$ 889,192
Operation and maintenance expense	138,600	129,045
Depreciation and amortization expense	96,065	88,374
Taxes, other than income	64,488	62,773
Operating income	236,464	242,083
Other non-operating expense	(7,723)	(2,557)
Interest charges	27,849	31,509
Income before income taxes	200,892	208,017
Income tax expense (benefit)	43,246	(106,115)
Net income	$ 157,646	$ 314,132
Basic net income per share	$ 1.38	$ 2.89
Diluted net income per share	1.38	2.89
Cash dividends per share	$ 0.525	$ 0.485
Basic weighted average shares outstanding	113,800	108,564
Diluted weighted average shares outstanding	113,832	108,564
Other comprehensive income (loss), net of tax
Net unrealized holding gains (losses) on available-for-sale securities, net of tax of $92, $490, $(246) and $893	$ 0	$ (107)
Cash flow hedges:
Amortization and unrealized gain (loss) on interest rate agreements, net of tax of $2,460, $(10,667), $8,486 and $44,194	(22,258)	(955)
Total other comprehensive income (loss)	(22,258)	(1,062)
Total comprehensive income	135,388	313,070
Operating Segments | Distribution segment
Operating revenues
Total operating revenues	838,835	860,792
Operation and maintenance expense	105,767	103,215
Depreciation and amortization expense	69,709	65,434
Taxes, other than income	56,190	55,107
Operating income	169,437	173,278
Other non-operating expense	(6,477)	(1,922)
Interest charges	18,210	21,368
Income before income taxes	144,750	149,988
Income tax expense (benefit)	30,365	(99,111)
Net income	114,385	249,099
Operating Segments | Pipeline and storage segment
Operating revenues
Total operating revenues	134,470	126,463
Operation and maintenance expense	33,147	26,140
Depreciation and amortization expense	26,356	22,940
Taxes, other than income	8,298	7,666
Operating income	67,027	68,805
Other non-operating expense	(1,246)	(635)
Interest charges	9,639	10,141
Income before income taxes	56,142	58,029
Income tax expense (benefit)	12,881	(7,004)
Net income	43,261	65,033
Intersegment eliminations
Operating revenues
Total operating revenues	(95,523)	(98,063)
Operation and maintenance expense	(314)	(310)
Depreciation and amortization expense	0	0
Taxes, other than income	0	0
Operating income	0	0
Other non-operating expense	0	0
Interest charges	0	0
Income before income taxes	0	0
Income tax expense (benefit)	0	0
Net income	0	0
Natural Gas, US Regulated
Operating revenues
Cost of Revenue	342,165	366,917
Natural Gas, US Regulated | Operating Segments | Distribution segment
Operating revenues
Cost of Revenue	437,732	463,758
Natural Gas, US Regulated | Operating Segments | Pipeline and storage segment
Operating revenues
Cost of Revenue	(358)	912
Natural Gas, US Regulated | Intersegment eliminations
Operating revenues
Cost of Revenue	$ (95,209)	$ (97,753)

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (PARENTHETICAL) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Net unrealized holding gains (losses) on available-for-sale securities, tax	$ 0	$ (62)
Amortization and unrealized gain (loss) on interest rate agreements, tax	$ (6,580)	$ (549)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Cash Flows From Operating Activities
Net income	$ 157,646	$ 314,132
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	96,065	88,374
Deferred income taxes	40,339	53,149
One-time income tax benefit	0	(161,884)
Other	6,231	6,915
Net assets / liabilities from risk management activities	(2,458)	2,030
Net change in operating assets and liabilities	(133,139)	(129,478)
Net cash provided by operating activities	164,684	173,238
Cash Flows From Investing Activities
Capital expenditures	(416,404)	(383,238)
Debt and equity securities activities, net	(963)	(135)
Other, net	2,074	2,001
Net cash used in investing activities	(415,293)	(381,372)
Cash Flows From Financing Activities
Net decrease in short-term debt	(575,780)	(110,929)
Net proceeds from equity offering	494,734	395,099
Issuance of common stock through stock purchase and employee retirement plans	4,241	5,660
Proceeds from issuance of long-term debt	596,994	0
Cash dividends paid	(58,722)	(51,837)
Debt issuance costs	(6,432)	0
Other	0	(1,518)
Net cash provided by financing activities	455,035	236,475
Net increase in cash and cash equivalents	204,426	28,341
Cash and cash equivalents at beginning of period	13,771	26,409
Cash and cash equivalents at end of period	$ 218,197	$ 54,750

Nature of Business

Nature of Business	3 Months Ended
	Dec. 31, 2018
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 December 31, 2018 , 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	3 Months Ended
	Dec. 31, 2018
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 three -month period ended December 31, 2018 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 . Accounting pronouncements adopted in fiscal 2019 In May 2014, the Financial Accounting Standards Board (FASB) issued a comprehensive new revenue recognition standard that superseded virtually all existing revenue recognition guidance under generally accepted accounting principles in the United States. Under the new standard, an entity recognizes revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. We adopted the new guidance October 1, 2018 using the modified retrospective method. See Note 5 for our discussion of the effects of implementing this standard. In January 2016, the FASB issued guidance related to the classification and measurement of financial instruments. The amendments modify the accounting and presentation for certain financial liabilities and equity investments not consolidated or reported using the equity method. Effective October 1, 2018, changes in the fair value of our equity securities formerly designated as available-for-sale are now recognized in other non-operating expense on our condensed consolidated statement of comprehensive income. 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 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 accumulated other comprehensive income. In March 2017, the FASB issued new guidance related to the statement of comprehensive income presentation of the components of net periodic benefit cost for an entity’s sponsored defined benefit pension and other postretirement plans. The new guidance requires entities to disaggregate the current service cost component of the net benefit cost from the other components and present it with other current compensation costs for related employees in the statement of comprehensive income. The other components of net benefit cost will be presented outside of income from operations on the statement of comprehensive income. 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). The Federal Energy Regulatory Commission (FERC), which regulates interstate transmission pipelines and also establishes, through its Uniform System of Accounts, accounting practices for rate-regulated entities, has issued guidance that states it will permit an election to either continue to capitalize non-service benefit costs or to cease capitalizing such costs for regulatory purposes. Accounting guidelines by the FERC are typically also followed by state commissions. As such, we continue to capitalize into property, plant and equipment all components of net periodic benefit cost for ratemaking purposes and will defer the non-service cost components as a regulatory asset for U.S. GAAP reporting purposes on a prospective basis in accordance with the new guidance. We adopted the new guidance beginning on October 1, 2018. We continue to present the service cost component of net periodic benefit cost within operation and maintenance expense; however, other components of the net periodic benefit cost are now presented separately within other non-operating expense on our condensed consolidated statement of comprehensive income. The changes in presentation were implemented on a retrospective basis in accordance with the guidance. In lieu of determining how each component of the net periodic benefit cost was actually reflected in the condensed statement of comprehensive income, we elected to utilize a practical expedient that permits the use of the amounts disclosed for each component of the net periodic benefit cost in our pension and post-retirement benefit plans footnote as the basis to retroactively apply this standard to all prior periods presented. The new standard did not have a material impact on our financial position, results of operations or cash flows. In August 2018, the FASB issued new guidance aligning the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract 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, beginning October 1, 2018. As a result of the new guidance, we will defer onto the balance sheet those up-front costs of cloud computing arrangements if they would have been capitalized in a similar on-premise software solution. The new standard did not have a material impact on our financial position, results of operations or cash flows. Accounting pronouncements that will be effective after fiscal 2019 In February 2016, the 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. The new standard will be effective for us beginning on October 1, 2019. The new leasing standard requires modified retrospective transition, which requires application of the new guidance at the beginning of the earliest comparative period presented in the year of adoption. In January 2018, the FASB issued a practical expedient to allow entities to not evaluate existing or expired land easements that were not previously accounted for as leases under the current guidance. In July 2018, the FASB issued a practical expedient providing an additional and optional transition method to adopt the standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. We are currently evaluating the effect of this standard and amendments on our financial position, results of operations, cash flows and business processes. 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, 2021; 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; however we are still evaluating the timing of our adoption. 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 December 31, 2018 and September 30, 2018 included the following: December 31, September 30, (In thousands) Regulatory assets: Pension and postretirement benefit costs $ 7,188 $ 6,496 Infrastructure mechanisms (1) 85,071 96,739 Deferred gas costs 11,621 1,927 Recoverable loss on reacquired debt 8,076 8,702 Deferred pipeline record collection costs 22,122 20,467 Rate case costs 1,866 2,741 Other 6,422 6,739 $ 142,366 $ 143,811 Regulatory liabilities: Regulatory excess deferred taxes (2) $ 740,896 $ 744,895 Regulatory cost of service reserve (3) 19,281 22,508 Regulatory cost of removal obligation 523,644 522,175 Deferred gas costs 85,820 94,705 Asset retirement obligation 12,887 12,887 APT annual adjustment mechanism 44,619 35,228 Pension and postretirement benefit costs 70,969 69,113 Other 14,354 9,486 $ 1,512,470 $ 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, $23.1 million 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

Segment Information	3 Months Ended
	Dec. 31, 2018
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 months ended December 31, 2018 and 2017 by segment are presented in the following tables: Three Months Ended December 31, 2018 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 838,181 $ 39,601 $ — $ 877,782 Intersegment revenues 654 94,869 (95,523 ) — Total operating revenues 838,835 134,470 (95,523 ) 877,782 Purchased gas cost 437,732 (358 ) (95,209 ) 342,165 Operation and maintenance expense 105,767 33,147 (314 ) 138,600 Depreciation and amortization expense 69,709 26,356 — 96,065 Taxes, other than income 56,190 8,298 — 64,488 Operating income 169,437 67,027 — 236,464 Other non-operating expense (6,477 ) (1,246 ) — (7,723 ) Interest charges 18,210 9,639 — 27,849 Income before income taxes 144,750 56,142 — 200,892 Income tax expense 30,365 12,881 — 43,246 Net income $ 114,385 $ 43,261 $ — $ 157,646 Capital expenditures $ 302,545 $ 113,859 $ — $ 416,404 Three Months Ended December 31, 2017 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 860,453 $ 28,739 $ — $ 889,192 Intersegment revenues 339 97,724 (98,063 ) — Total operating revenues 860,792 126,463 (98,063 ) 889,192 Purchased gas cost 463,758 912 (97,753 ) 366,917 Operation and maintenance expense 103,215 26,140 (310 ) 129,045 Depreciation and amortization expense 65,434 22,940 — 88,374 Taxes, other than income 55,107 7,666 — 62,773 Operating income 173,278 68,805 — 242,083 Other non-operating expense (1,922 ) (635 ) — (2,557 ) Interest charges 21,368 10,141 — 31,509 Income before income taxes 149,988 58,029 — 208,017 Income tax benefit (99,111 ) (7,004 ) — (106,115 ) Net income $ 249,099 $ 65,033 $ — $ 314,132 Capital expenditures $ 241,249 $ 141,989 $ — $ 383,238 Balance sheet information at December 31, 2018 and September 30, 2018 by segment is presented in the following tables: December 31, 2018 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Property, plant and equipment, net $ 7,889,901 $ 2,808,328 $ — $ 10,698,229 Total assets $ 11,836,888 $ 3,040,831 $ (2,261,930 ) $ 12,615,789 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	3 Months Ended
	Dec. 31, 2018
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. 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 months ended December 31, 2018 and 2017 are calculated as follows: Three Months Ended 2018 2017 (In thousands, except per share amounts) Basic Earnings Per Share Net income $ 157,646 $ 314,132 Less: Income allocated to participating securities 135 328 Income available to common shareholders $ 157,511 $ 313,804 Basic weighted average shares outstanding 113,800 108,564 Net income per share — Basic $ 1.38 $ 2.89 Diluted Earnings Per Share Income available to common shareholders $ 157,511 $ 313,804 Effect of dilutive shares — — Income available to common shareholders $ 157,511 $ 313,804 Basic weighted average shares outstanding 113,800 108,564 Dilutive shares (1) 32 — Diluted weighted average shares outstanding 113,832 108,564 Net income per share - Diluted $ 1.38 $ 2.89 (1) Dilutive shares were the result of the forward sale agreements entered into during fiscal 2019. See Note 7 for further discussion.

Revenue

Revenue	3 Months Ended
	Dec. 31, 2018
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 December 31, 2018 Distribution Pipeline and Storage (In thousands) Gas sales revenues: Residential $ 547,928 $ — Commercial 218,938 — Industrial 34,537 — Public authority and other 13,285 — Total gas sales revenues 814,688 — Transportation revenues 25,400 147,424 Miscellaneous revenues 6,950 1,682 Revenues from contracts with customers 847,038 149,106 Alternative revenue program revenues (8,739 ) (14,636 ) Other revenues 536 — Total operating revenues $ 838,835 $ 134,470 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 prices 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. These amounts can be either additional revenue or given back to customers depending on actual results as compared to the weather in our distribution segment or versus the benchmark in our pipeline and storage segment. 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	3 Months Ended
	Dec. 31, 2018
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 three months ended December 31, 2018 . Long-term debt at December 31, 2018 and September 30, 2018 consisted of the following: December 31, 2018 September 30, 2018 (In thousands) Unsecured 8.50% Senior Notes, due March 2019 $ 450,000 $ 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 — 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 (1,472 ) (4,439 ) Debt issuance cost 26,693 20,774 Current maturities 575,000 575,000 $ 3,084,779 $ 2,493,665 (1) Up to $200 million can be drawn under this term loan. 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 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 that expires on September 25, 2022 . The facility bears interest at a base rate or at a LIBOR-based rate for the applicable interest period, plus a spread 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 December 31, 2018 , there were no amounts outstanding under our commercial paper program. At September 30, 2018 , a total of $575.8 million was outstanding. Additionally, we have a $25 million 364-day unsecured facility and a $10 million 364-day unsecured revolving credit facility, which is used primarily to issue letters of credit. At December 31, 2018 , 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 December 31, 2018 , our total-debt-to-total-capitalization ratio, as defined in the agreements, was 42 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 December 31, 2018 . 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	3 Months Ended
	Dec. 31, 2018
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 months ended December 31, 2018 and 2017 . 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 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 Shelf Registration, At-the-Market Equity Sales Program and Equity Issuance 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 December 31, 2018 , approximately $1.8 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. During the three months ended December 31, 2018 , no shares of common stock were sold under the ATM equity sales program. 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 the underwriting discount, net proceeds from the offering were $494.7 million . Concurrently, we entered into separate forward sale agreements with two underwriters who borrowed and sold 2,668,464 shares of our common stock. Under the agreements we have the ability to settle these shares before March 31, 2020 at a price based on the offering price established on November 28, 2018. During the three months ended December 31, 2018 , no shares of common stock were settled under the forward sale agreements. If we had settled all shares under the forward agreements at December 31, 2018 , we would have received approximately $245.2 million , based on a net price of $91.90 per share. 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 loss before reclassifications — (22,716 ) (22,716 ) Amounts reclassified from accumulated other comprehensive income — 458 458 Net current-period other comprehensive loss — (22,258 ) (22,258 ) Cumulative effect of accounting change (See Note 2) (8,210 ) — (8,210 ) December 31, 2018 $ (86 ) $ (114,029 ) $ (114,115 ) 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 loss before reclassifications (107 ) (1,332 ) (1,439 ) Amounts reclassified from accumulated other comprehensive income — 377 377 Net current-period other comprehensive loss (107 ) (955 ) (1,062 ) December 31, 2017 $ 6,941 $ (113,257 ) $ (106,316 ) (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	3 Months Ended
	Dec. 31, 2018
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 months ended December 31, 2018 and 2017 are presented in the following table. 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 December 31 Pension Benefits Other Benefits 2018 2017 2018 2017 (In thousands) Components of net periodic pension cost: Service cost $ 4,045 $ 4,560 $ 2,702 $ 3,020 Interest cost (1) 6,799 6,430 2,961 2,727 Expected return on assets (1) (7,113 ) (6,917 ) (2,665 ) (2,002 ) Amortization of prior service cost (credit) (1) (58 ) (58 ) 43 3 Amortization of actuarial (gain) loss (1) 1,608 3,089 (2,045 ) (1,618 ) Net periodic pension cost $ 5,281 $ 7,104 $ 996 $ 2,130 (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	3 Months Ended
	Dec. 31, 2018
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. The plaintiffs seek over $1.0 million in damages for, among with others, wrongful death and personal injury. 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. There were no material changes to the purchase commitments for the three months ended December 31, 2018 . Leases We have entered into operating leases for towers, office and warehouse space, vehicles and heavy equipment used in our operations. During the three months ended December 31, 2018 , we executed amendments to some of our lease agreements that impacted terms as well as our future minimum lease payments. As of December 31, 2018 , 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 December 31, 2018 totaled $194.2 million Regulatory Matters Except for routine regulatory proceedings as discussed below, there were no material changes to regulatory matters for the three months ended December 31, 2018 . As of December 31, 2018 , regulatory proceedings were in progress in our Colorado, Kansas, Kentucky, Louisiana, Mid-Tex, Tennessee, Virginia and West Texas service areas. These 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 , all jurisdictions are addressing impacts of the TCJA.

Financial Instruments

Financial Instruments	3 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instruments	Financial Instruments We currently use financial instruments to mitigate commodity price risk and interest rate risk. The objectives and strategies for using financial instruments and the related accounting for these financial instruments are fully described in Notes 2 and 13 to the consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2018 . During the three months ended December 31, 2018 , 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 anticipate hedging 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 We periodically manage interest rate risk by entering into financial instruments to effectively fix the Treasury yield component of the interest cost associated with anticipated financings. As of December 31, 2018 , we had forward starting interest rate swaps to effectively fix the Treasury yield component associated with the anticipated issuance of $450 million unsecured senior notes in fiscal 2019 at 3.78% , which we designated as a cash flow hedge at the time the swaps were executed. As of December 31, 2018 , we had $47.7 million of net realized losses in accumulated other comprehensive income (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 2045. 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 December 31, 2018 , 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 December 31, 2018 , we had 14,353 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 December 31, 2018 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 December 31, 2018 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) December 31, 2018 Designated As Hedges: Interest rate swap agreements Other current assets / Other current liabilities $ — $ (85,930 ) Total — (85,930 ) Not Designated As Hedges: Commodity contracts Other current assets / Other current liabilities 3,241 (1,265 ) Commodity contracts Deferred charges and other assets / Deferred credits and other liabilities 285 — Total 3,526 (1,265 ) Gross / Net Financial Instruments $ 3,526 $ (87,195 ) Balance Sheet Location Assets Liabilities (In thousands) September 30, 2018 Designated As Hedges: Interest rate swap agreements 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, our distribution segment has interest rate swap agreements, which we designated as a cash flow hedge at the time the swaps 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 December 31, 2018 and 2017 was $0.6 million and $0.6 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 months ended December 31, 2018 and 2017 . 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 2018 2017 (In thousands) Increase (decrease) in fair value: Interest rate agreements $ (22,716 ) $ (1,332 ) Recognition of losses in earnings due to settlements: Interest rate agreements 458 377 Total other comprehensive income (loss) from hedging, net of tax $ (22,258 ) $ (955 ) 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 December 31, 2018 , 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. However, the table below does not include the expected recognition in earnings of our outstanding interest rate agreements as those instruments have not yet settled. Interest Rate Agreements (In thousands) Next twelve months $ (1,878 ) Thereafter (45,827 ) Total $ (47,705 ) Financial Instruments Not Designated as Hedges As discussed above, financial instruments 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	3 Months Ended
	Dec. 31, 2018
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 three months ended December 31, 2018 , 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 December 31, 2018 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 December 31, 2018 (In thousands) Assets: Financial instruments $ — $ 3,526 $ — $ — $ 3,526 Debt and equity securities Registered investment companies 37,241 — — — 37,241 Bond mutual funds 21,523 — — — 21,523 Bonds (2) — 30,096 — — 30,096 Money market funds — 3,319 — — 3,319 Total debt and equity securities 58,764 33,415 — — 92,179 Total assets $ 58,764 $ 36,941 $ — $ — $ 95,705 Liabilities: Financial instruments $ — $ 87,195 $ — $ — $ 87,195 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 December 31, 2018 and September 30, 2018 , our available-for-sale debt securities were recorded at amortized cost of $30.2 million and $31.5 million . At December 31, 2018 , we maintained investments in bonds that have contractual maturity dates ranging from January 2019 through December 2021. 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 December 31, 2018 and September 30, 2018 : December 31, 2018 September 30, 2018 (In thousands) Carrying Amount $ 3,685,000 $ 3,085,000 Fair Value $ 3,746,697 $ 3,161,679

Concentration of Credit Risk

Concentration of Credit Risk	3 Months Ended
	Dec. 31, 2018
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 three months ended December 31, 2018 , 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	3 Months Ended
	Dec. 31, 2018
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 $161.9 million income tax benefit in our condensed consolidated statement of comprehensive income during the first quarter of fiscal 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 December 31, 2018 and September 30, 2018, this liability totaled $740.9 million and $744.9 million . We have and continue to work with our regulators in each jurisdiction to fully incorporate the effects of the TCJA into customer bills. As of December 31, 2018, we have received approval from regulators to update our cost of service rates to reflect the decrease in the statutory income tax rate in our Colorado, Kansas, Kentucky, Louisiana, Mississippi, Tennessee and Texas service areas. We continue to work with regulators in Virginia to reflect the effects of the lower statutory income tax rate in our cost of service in rates. 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 December 31, 2018, we received approval from regulators to return these liabilities to customers in Colorado, Kansas, Louisiana and Texas. This regulatory liability totaled $19.3 million and $22.5 million as of December 31, 2018 and September 30, 2018. As of December 31, 2018, we received approval from regulators to return excess deferred taxes in Colorado, Kentucky, Louisiana, Mississippi, Tennessee and Texas 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)	3 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Significant accounting policies	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 . Accounting pronouncements adopted in fiscal 2019 In May 2014, the Financial Accounting Standards Board (FASB) issued a comprehensive new revenue recognition standard that superseded virtually all existing revenue recognition guidance under generally accepted accounting principles in the United States. Under the new standard, an entity recognizes revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. We adopted the new guidance October 1, 2018 using the modified retrospective method. See Note 5 for our discussion of the effects of implementing this standard. In January 2016, the FASB issued guidance related to the classification and measurement of financial instruments. The amendments modify the accounting and presentation for certain financial liabilities and equity investments not consolidated or reported using the equity method. Effective October 1, 2018, changes in the fair value of our equity securities formerly designated as available-for-sale are now recognized in other non-operating expense on our condensed consolidated statement of comprehensive income. 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 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 accumulated other comprehensive income. In March 2017, the FASB issued new guidance related to the statement of comprehensive income presentation of the components of net periodic benefit cost for an entity’s sponsored defined benefit pension and other postretirement plans. The new guidance requires entities to disaggregate the current service cost component of the net benefit cost from the other components and present it with other current compensation costs for related employees in the statement of comprehensive income. The other components of net benefit cost will be presented outside of income from operations on the statement of comprehensive income. 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). The Federal Energy Regulatory Commission (FERC), which regulates interstate transmission pipelines and also establishes, through its Uniform System of Accounts, accounting practices for rate-regulated entities, has issued guidance that states it will permit an election to either continue to capitalize non-service benefit costs or to cease capitalizing such costs for regulatory purposes. Accounting guidelines by the FERC are typically also followed by state commissions. As such, we continue to capitalize into property, plant and equipment all components of net periodic benefit cost for ratemaking purposes and will defer the non-service cost components as a regulatory asset for U.S. GAAP reporting purposes on a prospective basis in accordance with the new guidance. We adopted the new guidance beginning on October 1, 2018. We continue to present the service cost component of net periodic benefit cost within operation and maintenance expense; however, other components of the net periodic benefit cost are now presented separately within other non-operating expense on our condensed consolidated statement of comprehensive income. The changes in presentation were implemented on a retrospective basis in accordance with the guidance. In lieu of determining how each component of the net periodic benefit cost was actually reflected in the condensed statement of comprehensive income, we elected to utilize a practical expedient that permits the use of the amounts disclosed for each component of the net periodic benefit cost in our pension and post-retirement benefit plans footnote as the basis to retroactively apply this standard to all prior periods presented. The new standard did not have a material impact on our financial position, results of operations or cash flows. In August 2018, the FASB issued new guidance aligning the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract 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, beginning October 1, 2018. As a result of the new guidance, we will defer onto the balance sheet those up-front costs of cloud computing arrangements if they would have been capitalized in a similar on-premise software solution. The new standard did not have a material impact on our financial position, results of operations or cash flows. Accounting pronouncements that will be effective after fiscal 2019 In February 2016, the 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. The new standard will be effective for us beginning on October 1, 2019. The new leasing standard requires modified retrospective transition, which requires application of the new guidance at the beginning of the earliest comparative period presented in the year of adoption. In January 2018, the FASB issued a practical expedient to allow entities to not evaluate existing or expired land easements that were not previously accounted for as leases under the current guidance. In July 2018, the FASB issued a practical expedient providing an additional and optional transition method to adopt the standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. We are currently evaluating the effect of this standard and amendments on our financial position, results of operations, cash flows and business processes. 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, 2021; 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; however we are still evaluating the timing of our adoption.
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.
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 .
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 prices 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. These amounts can be either additional revenue or given back to customers depending on actual results as compared to the weather in our distribution segment or versus the benchmark in our pipeline and storage segment. 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)	3 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Schedule of Regulatory Assets	Significant regulatory assets and liabilities as of December 31, 2018 and September 30, 2018 included the following: December 31, September 30, (In thousands) Regulatory assets: Pension and postretirement benefit costs $ 7,188 $ 6,496 Infrastructure mechanisms (1) 85,071 96,739 Deferred gas costs 11,621 1,927 Recoverable loss on reacquired debt 8,076 8,702 Deferred pipeline record collection costs 22,122 20,467 Rate case costs 1,866 2,741 Other 6,422 6,739 $ 142,366 $ 143,811 Regulatory liabilities: Regulatory excess deferred taxes (2) $ 740,896 $ 744,895 Regulatory cost of service reserve (3) 19,281 22,508 Regulatory cost of removal obligation 523,644 522,175 Deferred gas costs 85,820 94,705 Asset retirement obligation 12,887 12,887 APT annual adjustment mechanism 44,619 35,228 Pension and postretirement benefit costs 70,969 69,113 Other 14,354 9,486 $ 1,512,470 $ 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, $23.1 million 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.
Schedule of Regulatory Liabilities	Significant regulatory assets and liabilities as of December 31, 2018 and September 30, 2018 included the following: December 31, September 30, (In thousands) Regulatory assets: Pension and postretirement benefit costs $ 7,188 $ 6,496 Infrastructure mechanisms (1) 85,071 96,739 Deferred gas costs 11,621 1,927 Recoverable loss on reacquired debt 8,076 8,702 Deferred pipeline record collection costs 22,122 20,467 Rate case costs 1,866 2,741 Other 6,422 6,739 $ 142,366 $ 143,811 Regulatory liabilities: Regulatory excess deferred taxes (2) $ 740,896 $ 744,895 Regulatory cost of service reserve (3) 19,281 22,508 Regulatory cost of removal obligation 523,644 522,175 Deferred gas costs 85,820 94,705 Asset retirement obligation 12,887 12,887 APT annual adjustment mechanism 44,619 35,228 Pension and postretirement benefit costs 70,969 69,113 Other 14,354 9,486 $ 1,512,470 $ 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, $23.1 million 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)	3 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Income statements and capital expenditures for the three months ended December 31, 2018 and 2017 by segment are presented in the following tables: Three Months Ended December 31, 2018 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 838,181 $ 39,601 $ — $ 877,782 Intersegment revenues 654 94,869 (95,523 ) — Total operating revenues 838,835 134,470 (95,523 ) 877,782 Purchased gas cost 437,732 (358 ) (95,209 ) 342,165 Operation and maintenance expense 105,767 33,147 (314 ) 138,600 Depreciation and amortization expense 69,709 26,356 — 96,065 Taxes, other than income 56,190 8,298 — 64,488 Operating income 169,437 67,027 — 236,464 Other non-operating expense (6,477 ) (1,246 ) — (7,723 ) Interest charges 18,210 9,639 — 27,849 Income before income taxes 144,750 56,142 — 200,892 Income tax expense 30,365 12,881 — 43,246 Net income $ 114,385 $ 43,261 $ — $ 157,646 Capital expenditures $ 302,545 $ 113,859 $ — $ 416,404 Three Months Ended December 31, 2017 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Operating revenues from external parties $ 860,453 $ 28,739 $ — $ 889,192 Intersegment revenues 339 97,724 (98,063 ) — Total operating revenues 860,792 126,463 (98,063 ) 889,192 Purchased gas cost 463,758 912 (97,753 ) 366,917 Operation and maintenance expense 103,215 26,140 (310 ) 129,045 Depreciation and amortization expense 65,434 22,940 — 88,374 Taxes, other than income 55,107 7,666 — 62,773 Operating income 173,278 68,805 — 242,083 Other non-operating expense (1,922 ) (635 ) — (2,557 ) Interest charges 21,368 10,141 — 31,509 Income before income taxes 149,988 58,029 — 208,017 Income tax benefit (99,111 ) (7,004 ) — (106,115 ) Net income $ 249,099 $ 65,033 $ — $ 314,132 Capital expenditures $ 241,249 $ 141,989 $ — $ 383,238 Balance sheet information at December 31, 2018 and September 30, 2018 by segment is presented in the following tables: December 31, 2018 Distribution Pipeline and Storage Eliminations Consolidated (In thousands) Property, plant and equipment, net $ 7,889,901 $ 2,808,328 $ — $ 10,698,229 Total assets $ 11,836,888 $ 3,040,831 $ (2,261,930 ) $ 12,615,789 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)	3 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	Basic and diluted earnings per share for the three months ended December 31, 2018 and 2017 are calculated as follows: Three Months Ended 2018 2017 (In thousands, except per share amounts) Basic Earnings Per Share Net income $ 157,646 $ 314,132 Less: Income allocated to participating securities 135 328 Income available to common shareholders $ 157,511 $ 313,804 Basic weighted average shares outstanding 113,800 108,564 Net income per share — Basic $ 1.38 $ 2.89 Diluted Earnings Per Share Income available to common shareholders $ 157,511 $ 313,804 Effect of dilutive shares — — Income available to common shareholders $ 157,511 $ 313,804 Basic weighted average shares outstanding 113,800 108,564 Dilutive shares (1) 32 — Diluted weighted average shares outstanding 113,832 108,564 Net income per share - Diluted $ 1.38 $ 2.89 (1) Dilutive shares were the result of the forward sale agreements entered into during fiscal 2019. See Note 7 for further discussion.

Revenue (Table)

Revenue (Table)	3 Months Ended
	Dec. 31, 2018
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 December 31, 2018 Distribution Pipeline and Storage (In thousands) Gas sales revenues: Residential $ 547,928 $ — Commercial 218,938 — Industrial 34,537 — Public authority and other 13,285 — Total gas sales revenues 814,688 — Transportation revenues 25,400 147,424 Miscellaneous revenues 6,950 1,682 Revenues from contracts with customers 847,038 149,106 Alternative revenue program revenues (8,739 ) (14,636 ) Other revenues 536 — Total operating revenues $ 838,835 $ 134,470

Debt (Table)

Debt (Table)	3 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	Long-term debt at December 31, 2018 and September 30, 2018 consisted of the following: December 31, 2018 September 30, 2018 (In thousands) Unsecured 8.50% Senior Notes, due March 2019 $ 450,000 $ 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 — 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 (1,472 ) (4,439 ) Debt issuance cost 26,693 20,774 Current maturities 575,000 575,000 $ 3,084,779 $ 2,493,665 (1) Up to $200 million can be drawn under this term loan.

Shareholders' Equity (Table)

Shareholders' Equity (Table)	3 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Schedule of Stockholders Equity	The following tables present a reconciliation of changes in stockholders' equity for the three months ended December 31, 2018 and 2017 . 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 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
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 loss before reclassifications — (22,716 ) (22,716 ) Amounts reclassified from accumulated other comprehensive income — 458 458 Net current-period other comprehensive loss — (22,258 ) (22,258 ) Cumulative effect of accounting change (See Note 2) (8,210 ) — (8,210 ) December 31, 2018 $ (86 ) $ (114,029 ) $ (114,115 ) 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 loss before reclassifications (107 ) (1,332 ) (1,439 ) Amounts reclassified from accumulated other comprehensive income — 377 377 Net current-period other comprehensive loss (107 ) (955 ) (1,062 ) December 31, 2017 $ 6,941 $ (113,257 ) $ (106,316 ) (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)	3 Months Ended
	Dec. 31, 2018
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 months ended December 31, 2018 and 2017 are presented in the following table. 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 December 31 Pension Benefits Other Benefits 2018 2017 2018 2017 (In thousands) Components of net periodic pension cost: Service cost $ 4,045 $ 4,560 $ 2,702 $ 3,020 Interest cost (1) 6,799 6,430 2,961 2,727 Expected return on assets (1) (7,113 ) (6,917 ) (2,665 ) (2,002 ) Amortization of prior service cost (credit) (1) (58 ) (58 ) 43 3 Amortization of actuarial (gain) loss (1) 1,608 3,089 (2,045 ) (1,618 ) Net periodic pension cost $ 5,281 $ 7,104 $ 996 $ 2,130 (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)	3 Months Ended
	Dec. 31, 2018
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 December 31, 2018 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 December 31, 2018 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) December 31, 2018 Designated As Hedges: Interest rate swap agreements Other current assets / Other current liabilities $ — $ (85,930 ) Total — (85,930 ) Not Designated As Hedges: Commodity contracts Other current assets / Other current liabilities 3,241 (1,265 ) Commodity contracts Deferred charges and other assets / Deferred credits and other liabilities 285 — Total 3,526 (1,265 ) Gross / Net Financial Instruments $ 3,526 $ (87,195 ) Balance Sheet Location Assets Liabilities (In thousands) September 30, 2018 Designated As Hedges: Interest rate swap agreements 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 months ended December 31, 2018 and 2017 . 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 2018 2017 (In thousands) Increase (decrease) in fair value: Interest rate agreements $ (22,716 ) $ (1,332 ) Recognition of losses in earnings due to settlements: Interest rate agreements 458 377 Total other comprehensive income (loss) from hedging, net of tax $ (22,258 ) $ (955 )
Schedule Of Expected Deferred Gains (Losses) Recognition	The following amounts, net of deferred taxes, represent the expected recognition in earnings, as of December 31, 2018 , 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. However, the table below does not include the expected recognition in earnings of our outstanding interest rate agreements as those instruments have not yet settled. Interest Rate Agreements (In thousands) Next twelve months $ (1,878 ) Thereafter (45,827 ) Total $ (47,705 )

Fair Value Measurements (Table)

Fair Value Measurements (Table)	3 Months Ended
	Dec. 31, 2018
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 December 31, 2018 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 December 31, 2018 (In thousands) Assets: Financial instruments $ — $ 3,526 $ — $ — $ 3,526 Debt and equity securities Registered investment companies 37,241 — — — 37,241 Bond mutual funds 21,523 — — — 21,523 Bonds (2) — 30,096 — — 30,096 Money market funds — 3,319 — — 3,319 Total debt and equity securities 58,764 33,415 — — 92,179 Total assets $ 58,764 $ 36,941 $ — $ — $ 95,705 Liabilities: Financial instruments $ — $ 87,195 $ — $ — $ 87,195 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 December 31, 2018 and September 30, 2018 : December 31, 2018 September 30, 2018 (In thousands) Carrying Amount $ 3,685,000 $ 3,085,000 Fair Value $ 3,746,697 $ 3,161,679

Nature of Business (Details)

Nature of Business (Details)	Dec. 31, 2018customerstateregulated_distribution_division
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of customers serviced | customer	3,000,000
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	Dec. 31, 2018	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	$ 142,366		$ 143,811
Regulatory Liabilities [Line Items]
Regulatory liabilities	1,512,470		1,510,997
Regulatory excess deferred taxes
Regulatory Liabilities [Line Items]
Regulatory liabilities	740,896		744,895
Regulatory cost of service reserve
Regulatory Liabilities [Line Items]
Regulatory liabilities	19,281		22,508
Regulatory cost of removal obligation
Regulatory Liabilities [Line Items]
Regulatory liabilities	523,644		522,175
Deferred gas costs
Regulatory Liabilities [Line Items]
Regulatory liabilities	85,820		94,705
Asset retirement obligation
Regulatory Liabilities [Line Items]
Regulatory liabilities	12,887		12,887
Other
Regulatory Liabilities [Line Items]
Regulatory liabilities	14,354		9,486
APT annual adjustment mechanism
Regulatory Liabilities [Line Items]
Regulatory liabilities	44,619		35,228
Pension and other postreitrement plans costs
Regulatory Liabilities [Line Items]
Regulatory liabilities	70,969		69,113
Pension and other postreitrement plans costs
Regulatory Asset [Line Items]
Regulatory assets	7,188		6,496
Infrastructure mechanisms
Regulatory Asset [Line Items]
Regulatory assets	85,071		96,739
Deferred gas costs
Regulatory Asset [Line Items]
Regulatory assets	11,621		1,927
Recoverable loss on reacquired debt
Regulatory Asset [Line Items]
Regulatory assets	8,076		8,702
Deferred pipeline record collection costs
Regulatory Asset [Line Items]
Regulatory assets	22,122		20,467
Rate case costs
Regulatory Asset [Line Items]
Regulatory assets	1,866		2,741
Other
Regulatory Asset [Line Items]
Regulatory assets	6,422		$ 6,739
Other Current Liabilities | Regulatory excess deferred taxes
Regulatory Liabilities [Line Items]
Regulatory liabilities	$ 23,100

Segment Information (Details)

Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2018
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	$ 877,782	$ 889,192
Operation and maintenance expense	138,600	129,045
Depreciation and amortization expense	96,065	88,374
Taxes, other than income	64,488	62,773
Operating income	236,464	242,083
Other non-operating expense	(7,723)	(2,557)
Interest charges	27,849	31,509
Income before income taxes	200,892	208,017
Income tax (benefit) expense	43,246	(106,115)
Net income	157,646	314,132
Capital expenditures	416,404	383,238
Segment Reporting Information, Balance Sheet [Abstract]
Property, plant and equipment, net	10,698,229		$ 10,371,147
Total assets	12,615,789		11,874,437
Operating Segments | Distribution
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	838,835	860,792
Operation and maintenance expense	105,767	103,215
Depreciation and amortization expense	69,709	65,434
Taxes, other than income	56,190	55,107
Operating income	169,437	173,278
Other non-operating expense	(6,477)	(1,922)
Interest charges	18,210	21,368
Income before income taxes	144,750	149,988
Income tax (benefit) expense	30,365	(99,111)
Net income	114,385	249,099
Capital expenditures	302,545	241,249
Segment Reporting Information, Balance Sheet [Abstract]
Property, plant and equipment, net	7,889,901		7,644,693
Total assets	11,836,888		11,109,128
Operating Segments | Pipeline and Storage
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	134,470	126,463
Operation and maintenance expense	33,147	26,140
Depreciation and amortization expense	26,356	22,940
Taxes, other than income	8,298	7,666
Operating income	67,027	68,805
Other non-operating expense	(1,246)	(635)
Interest charges	9,639	10,141
Income before income taxes	56,142	58,029
Income tax (benefit) expense	12,881	(7,004)
Net income	43,261	65,033
Capital expenditures	113,859	141,989
Segment Reporting Information, Balance Sheet [Abstract]
Property, plant and equipment, net	2,808,328		2,726,454
Total assets	3,040,831		2,963,480
Intersegment eliminations
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	(95,523)	(98,063)
Operation and maintenance expense	(314)	(310)
Depreciation and amortization expense	0	0
Taxes, other than income	0	0
Operating income	0	0
Other non-operating expense	0	0
Interest charges	0	0
Income before income taxes	0	0
Income tax (benefit) expense	0	0
Net income	0	0
Capital expenditures	0	0
Intersegment eliminations | Intersegment eliminations
Segment Reporting Information, Balance Sheet [Abstract]
Property, plant and equipment, net	0		0
Total assets	(2,261,930)		$ (2,198,171)
Reportable Subsegments
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	877,782	889,192
Reportable Subsegments | Distribution
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	838,181	860,453
Reportable Subsegments | Pipeline and Storage
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	39,601	28,739
Reportable Subsegments | Intersegment eliminations
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	0	0
Intersubsegment Eliminations
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	0	0
Intersubsegment Eliminations | Distribution
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	654	339
Intersubsegment Eliminations | Pipeline and Storage
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	94,869	97,724
Intersubsegment Eliminations | Intersegment eliminations
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	(95,523)	(98,063)
Natural Gas, US Regulated
Segment Reporting Information Profit Loss [Abstract]
Cost of Revenue	342,165	366,917
Natural Gas, US Regulated | Operating Segments | Distribution
Segment Reporting Information Profit Loss [Abstract]
Cost of Revenue	437,732	463,758
Natural Gas, US Regulated | Operating Segments | Pipeline and Storage
Segment Reporting Information Profit Loss [Abstract]
Cost of Revenue	(358)	912
Natural Gas, US Regulated | Intersegment eliminations
Segment Reporting Information Profit Loss [Abstract]
Cost of Revenue	$ (95,209)	$ (97,753)

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Basic and Diluted Earnings Per Share, Continuing Operations [Abstract]
Net Income	$ 157,646	$ 314,132
Income allocated to participating securities	135	328
Income available to common shareholders	$ 157,511	$ 313,804
Basic weighted average shares outstanding	113,800	108,564
Basic net income per share	$ 1.38	$ 2.89
Effect of dilutive shares	$ 0	$ 0
Income available to common shareholders, diluted	$ 157,511	$ 313,804
Additional dilutive shares	32	0
Diluted weighted average shares outstanding	113,832	108,564
Diluted net income per share	$ 1.38	$ 2.89

Revenue (Details)

Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 877,782	$ 889,192
Distribution segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	847,038
Alternative Revenue Program Revenues	(8,739)
Other Revenues	536
Pipeline and storage segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	149,106
Alternative Revenue Program Revenues	(14,636)
Other Revenues	0
Gas sales revenue [Member] | Distribution segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	814,688
Gas sales revenue [Member] | Pipeline and storage segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	0
Gas sales revenue [Member] | Residential Customers [Member] | Distribution segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	547,928
Gas sales revenue [Member] | Residential Customers [Member] | Pipeline and storage segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	0
Gas sales revenue [Member] | Commercial Customers [Member] | Distribution segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	218,938
Gas sales revenue [Member] | Commercial Customers [Member] | Pipeline and storage segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	0
Gas sales revenue [Member] | Industrial Customers [Member] | Distribution segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	34,537
Gas sales revenue [Member] | Industrial Customers [Member] | Pipeline and storage segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	0
Gas sales revenue [Member] | Public Authority and Other Customers [Member] | Distribution segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	13,285
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
Transportation revenue [Member] | Distribution segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	25,400
Transportation revenue [Member] | Pipeline and storage segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	147,424
Miscellaneous revenue [Member] | Distribution segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	6,950
Miscellaneous revenue [Member] | Pipeline and storage segment
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customer	1,682
Operating Segments | Distribution segment
Disaggregation of Revenue [Line Items]
Total operating revenues	838,835	860,792
Operating Segments | Pipeline and storage segment
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 134,470	$ 126,463

Debt - Schedule of Long-term De

Debt - Schedule of Long-term Debt Instruments (Details) - USD ($)	Dec. 31, 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	(1,472,000)	(4,439,000)
Debt issuance cost	26,693,000	20,774,000
Current maturities	575,000,000	575,000,000
Long-term debt	3,084,779,000	2,493,665,000
Unsecured 8.50% Senior Notes, due March 2019
Debt Instrument [Line Items]
Total long-term debt	$ 450,000,000	$ 450,000,000
Interest rate	8.50%	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
Unsecured 4.30% Senior Notes, due 2048 [Member]
Debt Instrument [Line Items]
Total long-term debt	$ 600,000,000	$ 0
Interest rate	4.30%	4.30%

Debt - Narrative (Details)

Debt - Narrative (Details) - USD ($)	3 Months Ended
	Dec. 31, 2018	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	42.00%
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	0	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 [Member]
Line Of Credit Facility [Line Items]
Total long-term debt	$ 600,000,000	$ 0
Interest rate	4.30%	4.30%
Proceeds from Issuance of Debt	$ 590,600,000
Effective interest rate	4.37%
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
	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2018	Sep. 30, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock outstanding (in shares)	116,892,959		111,273,683
Shareholders' equity, beginning balance	$ 4,769,951	$ 3,898,666
Net Income	157,646	314,132
Other Comprehensive Loss, Net of Tax	(22,258)	(1,062)
Cash dividends	(58,722)	(51,837)
Stock Issued or Granted During Period, Share-based Compensation [Abstract]
Public and other stock offerings	498,975	400,759
Stock-based compensation plans	2,603	2,962
Shareholders' equity, ending balance	$ 5,348,195	$ 4,563,620
Cash dividends per share	$ 0.525	$ 0.485
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock outstanding (in shares)	116,892,959	110,962,112	111,273,683	106,104,634
Shareholders' equity, beginning balance	$ 556	$ 531
Stock Issued or Granted During Period, Share-based Compensation [Abstract]
Public and other stock offerings (in shares)	5,434,812	4,621,518
Public and other stock offerings	$ 27	$ 22
Stock-based compensation plans (in shares)	184,464	235,960
Stock-based compensation plans	$ 1	$ 2
Shareholders' equity, ending balance	584	555
Additional Paid-in Capital [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shareholders' equity, beginning balance	2,974,926	2,536,365
Stock Issued or Granted During Period, Share-based Compensation [Abstract]
Public and other stock offerings	498,948	400,737
Stock-based compensation plans	2,602	2,960
Shareholders' equity, ending balance	3,476,476	2,940,062
Accumulated Other Comprehensive Income
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shareholders' equity, beginning balance	(83,647)	(105,254)
Other Comprehensive Loss, Net of Tax	(22,258)	(1,062)
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	(114,115)	(106,316)
Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shareholders' equity, beginning balance	1,878,116	1,467,024
Net Income	157,646	314,132
Cash dividends	(58,722)	(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	$ 1,985,250	$ 1,729,319

Shareholders' Equity - Schedule

Shareholders' Equity - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Oct. 01, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Shareholders' equity, beginning balance	$ 4,769,951	$ 3,898,666
Net current-period other comprehensive loss	(22,258)	(1,062)
Cummulative effect on accounting change, on equity or net assets			$ 8,200
Shareholders' equity, ending balance	5,348,195	4,563,620
Available- for-Sale Securities(1)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Shareholders' equity, beginning balance	8,124	7,048
Other comprehensive loss before reclassifications	0	(107)
Amounts reclassified from accumulated other comprehensive income	0	0
Net current-period other comprehensive loss	0	(107)
Cummulative effect on accounting change, on equity or net assets			(8,210)
Shareholders' equity, ending balance	(86)	6,941
Cash Flow Hedges | Interest rate agreements
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Shareholders' equity, beginning balance	(91,771)	(112,302)
Other comprehensive loss before reclassifications	(22,716)	(1,332)
Amounts reclassified from accumulated other comprehensive income	458	377
Net current-period other comprehensive loss	(22,258)	(955)
Cummulative effect on accounting change, on equity or net assets			$ 0
Shareholders' equity, ending balance	(114,029)	(113,257)
Accumulated Other Comprehensive Income
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Shareholders' equity, beginning balance	(83,647)	(105,254)
Other comprehensive loss before reclassifications	(22,716)	(1,439)
Amounts reclassified from accumulated other comprehensive income	458	377
Net current-period other comprehensive loss	(22,258)	(1,062)
Cummulative effect on accounting change, on equity or net assets	(8,210)
Shareholders' equity, ending balance	$ (114,115)	$ (106,316)

Shareholders' Equity - Narrativ

Shareholders' Equity - Narrative (Details) - USD ($)	Nov. 30, 2018	Nov. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Nov. 19, 2018	Nov. 13, 2018
Class of Stock [Line Items]
Gross proceeds from equity offering		$ 400,000,000
Net proceeds from equity offering		$ 395,100,000	$ 494,734,000	$ 395,099,000
Forward sales equity agreement, shares	2,668,464
Forward sales equity agreement, settlement date			Mar. 31, 2020
Forward sales equity agreement, settlements			$ 0
Forward sales equity agreement, settlement alternatives, cash, at fair value			$ 245,200,000
Forward sales equity agreement, forward rate per share			$ 91.90
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			$ 1,800,000,000
At-The-Market
Class of Stock [Line Items]
Value of shares authorized for issuance					$ 500,000,000
Stock Issued During Period, New Issues (in shares)			0
Common Stock Block Trade
Class of Stock [Line Items]
Stock Issued During Period, New Issues (in shares)	5,390,836	4,558,404
Gross proceeds from equity offering	$ 500,000,000
Net proceeds from equity offering	$ 494,700,000

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
	Dec. 31, 2018	Dec. 31, 2017
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4,045	$ 4,560
Interest cost	6,799	6,430
Expected return on assets	(7,113)	(6,917)
Amortization of prior service cost (credit)	(58)	(58)
Amortization of actuarial (gain) loss	1,608	3,089
Net periodic pension cost	5,281	7,104
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	2,702	3,020
Interest cost	2,961	2,727
Expected return on assets	(2,665)	(2,002)
Amortization of prior service cost (credit)	43	3
Amortization of actuarial (gain) loss	(2,045)	(1,618)
Net periodic pension cost	$ 996	$ 2,130

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Thousands	Mar. 29, 2018	Dec. 31, 2018
Loss Contingencies [Line Items]
Self-insurance retention expense		$ 1,000
Operating Leased Assets [Line Items]
Operating leases, future minimum payments due		$ 194,197
Minimum
Operating Leased Assets [Line Items]
Lease term of contract		1 year
Maximum
Operating Leased Assets [Line Items]
Lease term of contract		20 years
Civil Action, Dallas, Texas
Loss Contingencies [Line Items]
Damages sought	$ 1,000

Financial Instruments - Narrati

Financial Instruments - Narrative (Details)	3 Months Ended
	Dec. 31, 2018USD ($)MMcfBcf	Dec. 31, 2017USD ($)
Derivative [Line Items]
Net realized gain (loss)	$ (47,700,000)
Net gain (loss) on settled interest rate agreements	$ (600,000)	$ (600,000)
Gas Purchases | Not Designated as Hedging Instrument | Commodity contracts
Derivative [Line Items]
Hedging percent	33.00%
Energy measure | Bcf	18,900
Minimum | Gas Purchases | Not Designated as Hedging Instrument | Commodity contracts
Derivative [Line Items]
Hedging percent	25.00%
Maximum | Gas Purchases | Not Designated as Hedging Instrument | Commodity contracts
Derivative [Line Items]
Hedging percent	50.00%
Cash Flow Hedging | Designated as Hedging Instrument | Interest Rate Swap
Derivative [Line Items]
Notional amount	$ 450,000,000
Interest rate hedged	3.78%
Long | Gas Purchases | Not Designated as Hedging Instrument | Commodity contracts
Derivative [Line Items]
Energy measure | MMcf	14,353

Financial Instruments - Schedul

Financial Instruments - Schedule of Derivative Instruments in Statement of Financial Position, Fair Value (Details) - USD ($)	Dec. 31, 2018	Sep. 30, 2018
Derivatives Fair Value [Line Items]
Contract Netting	$ 0	$ 0
Net Financial Instruments, Assets	3,526,000	1,619,000
Cash collateral	0
Net Financial Instruments, Liabilities	(87,195,000)	(56,837,000)
Designated as Hedging Instrument
Derivatives Fair Value [Line Items]
Gross Financial Instruments, Assets	0	0
Gross Financial Instruments, Liabilities	(85,930,000)	(56,499,000)
Designated as Hedging Instrument | Other Current Assets | Interest rate agreements
Derivatives Fair Value [Line Items]
Gross Financial Instruments, Assets	0	0
Designated as Hedging Instrument | Other Current Liabilities | Interest rate agreements
Derivatives Fair Value [Line Items]
Gross Financial Instruments, Liabilities	(85,930,000)	(56,499,000)
Not Designated as Hedging Instrument
Derivatives Fair Value [Line Items]
Gross Financial Instruments, Assets	3,526,000	1,619,000
Gross Financial Instruments, Liabilities	(1,265,000)	(338,000)
Not Designated as Hedging Instrument | Other Current Assets | Commodity contracts
Derivatives Fair Value [Line Items]
Gross Financial Instruments, Assets	3,241,000	1,369,000
Not Designated as Hedging Instrument | Other Current Liabilities | Commodity contracts
Derivatives Fair Value [Line Items]
Gross Financial Instruments, Liabilities	(1,265,000)	(235,000)
Not Designated as Hedging Instrument | Deferred Charges and Other Assets | Commodity contracts
Derivatives Fair Value [Line Items]
Gross Financial Instruments, Assets	285,000	250,000
Not Designated as Hedging Instrument | Deferred Credits and Other Liabilities | Commodity contracts
Derivatives Fair Value [Line Items]
Gross Financial Instruments, Liabilities	$ 0	$ (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
	Dec. 31, 2018	Dec. 31, 2017
Increase (decrease) in fair value:
Interest rate agreements	$ (22,716)	$ (1,332)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Interest rate agreements	458	377
Total other comprehensive income (loss) from hedging, net of tax	$ (22,258)	$ (955)

Financial Instruments - Sched_3

Financial Instruments - Schedule Of Expected Deferred Gains (Losses) Recognition (Details) $ in Thousands	Dec. 31, 2018USD ($)
Derivative [Line Items]
Interest Rate Agreements	$ (47,705)
Next twelve months
Derivative [Line Items]
Interest Rate Agreements	(1,878)
Thereafter
Derivative [Line Items]
Interest Rate Agreements	$ (45,827)

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2018	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	3,526	1,619
Debt and equity securities	92,179	99,385
Total assets	95,705	101,004
Netting and Cash Collateral	0	0
Financial instruments net liability	87,195	56,837
Registered investment companies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity Securities	37,241	42,644
Bond mutual funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity Securities	21,523	21,507
Bonds2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	30,096	31,400
Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity Securities	3,319	3,834
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	58,764	64,151
Total assets	58,764	64,151
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	37,241	42,644
Fair Value Inputs Level 1 | Bond mutual funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity Securities	21,523	21,507
Fair Value Inputs Level 1 | Bonds(2)
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	3,526	1,619
Debt and equity securities	33,415	35,234
Total assets	36,941	36,853
Financial instruments gross liability	87,195	56,837
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(2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	30,096	31,400
Fair Value Inputs Level 2 | Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity Securities	3,319	3,834
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(2)
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 Thousands	Dec. 31, 2018	Sep. 30, 2018
Bonds2
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 30,207	$ 31,511

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Carrying Values and Estimated Fair Values of Debt Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Total long-term debt	$ 3,685,000	$ 3,085,000
Fair Value	$ 3,746,697	$ 3,161,679

Impact of the Tax Cuts and Jo_2

Impact of the Tax Cuts and Jobs Act of 2017 (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2018
Income Tax Examination [Line Items]
TCJA Income Tax Benefit		$ 161.9
Regulated operations recorded as a regulatory liability	$ 740.9		$ 744.9
TCJA additional liability due to tax rates used in rates	$ 19.3		$ 22.5
Minimum
Income Tax Examination [Line Items]
Return issuance period	13 years
Maximum
Income Tax Examination [Line Items]
Return issuance period	51 years