Atmos Energy (ATO) 10-Q 2 Aug 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Jun. 30, 2017	Jul. 28, 2017
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	Jun. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		106,065,596

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($)	Jun. 30, 2017	Sep. 30, 2016
ASSETS
Property, plant and equipment	$ 10,952,422,000	$ 10,142,506,000
Less accumulated depreciation and amortization	2,028,041,000	1,873,900,000
Net property, plant and equipment	8,924,381,000	8,268,606,000
Current assets
Cash and cash equivalents	69,777,000	47,534,000
Accounts receivable, net	250,224,000	215,880,000
Gas stored underground	151,656,000	179,070,000
Current assets held for sale	0	151,117,000
Other current assets	62,725,000	88,085,000
Total current assets	534,382,000	681,686,000
Goodwill	729,673,000	726,962,000
Noncurrent assets held for sale	0	28,616,000
Deferred charges and other assets	310,339,000	305,019,000
Total assets	10,498,775,000	10,010,889,000
Shareholders' equity
Common stock, no par value (stated at $.005 per share)	530,000	520,000
Additional paid-in capital	2,525,752,000	2,388,027,000
Accumulated other comprehensive income (loss)	(104,599,000)	(188,022,000)
Retained earnings	1,480,027,000	1,262,534,000
Shareholders' equity	3,901,710,000	3,463,059,000
Long-term debt	3,066,734,000	2,188,779,000
Total capitalization	6,968,444,000	5,651,838,000
Current liabilities
Accounts payable and accrued liabilities	164,365,000	196,485,000
Current liabilities held for sale	0	72,900,000
Other current liabilities	322,721,000	439,085,000
Short-term debt	258,573,000	829,811,000
Current maturities of long-term debt	0	250,000,000
Total current liabilities	745,659,000	1,788,281,000
Deferred income taxes	1,853,564,000	1,603,056,000
Regulatory cost of removal obligation	457,060,000	424,281,000
Pension and postretirement liabilities	304,919,000	297,743,000
Noncurrent liabilities held for sale	0	316,000
Deferred credits and other liabilities	169,129,000	245,374,000
Total shareholders' equity and liabilities	$ 10,498,775,000	$ 10,010,889,000

CONDENSED CONSOLIDATED BALANCE3

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (PARENTHETICALS) - $ / shares	Jun. 30, 2017	Sep. 30, 2016
Statement of Financial Position [Abstract]
Common Stock, No Par Value	$ 0.005	$ 0.005
Common Stock, Shares Authorized	200,000,000	200,000,000
Common Stock, Shares, Issued	106,059,875	103,930,560
Common Stock, Shares, Outstanding	106,059,875	103,930,560

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Operating revenues [Abstract]
Operating revenues	$ 526,501	$ 456,212	$ 2,294,855	$ 2,021,005
Purchase Gas Cost [Abstract]
Purchased gas cost	114,176	64,583	852,975	682,265
Operation and maintenance expense	128,690	131,388	385,867	379,073
Depreciation and amortization expense	80,023	72,880	234,648	214,927
Taxes, other than income, expense	62,948	58,965	185,611	171,959
Operating income	140,664	128,396	635,754	572,781
Miscellaneous income (expense)	(289)	1,118	(450)	(90)
Interest charges	28,498	27,679	86,472	84,775
Income (loss) from continuing operations before income taxes	111,877	101,835	548,832	487,916
Income tax expense (benefit)	41,069	35,692	201,974	177,224
Income from continuing operations	70,808	66,143	346,858	310,692
Income from discontinued operations, net of tax, before gain on disposal	0	5,050	10,994	5,172
Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			2,716	0
Income from discontinued operations, net of tax	0	5,050	13,710	5,172
Net income (loss)	$ 70,808	$ 71,193	$ 360,568	$ 315,864
Income (Loss) from Continuing Operations, Per Basic and Diluted Share	$ 0.67	$ 0.64	$ 3.27	$ 3.01
Income (Loss) from Discontinued Operation, Net of Tax, Per Basic and Diluted Share	0	0.05	0.13	0.05
Basic and diluted net income per share	0.67	0.69	3.40	3.06
Cash dividends per share	$ 0.45	$ 0.42	$ 1.35	$ 1.26
Weighted average shares outstanding:
Weighted Average Number of Shares Outstanding, Basic and Diluted	106,364	103,750	105,862	103,137
Distribution Segment [Member]
Operating revenues [Abstract]
Operating revenues	$ 494,060	$ 424,905	$ 2,211,257	$ 1,936,475
Purchase Gas Cost [Abstract]
Purchased gas cost	197,767	147,569	1,106,209	912,231
Operation and maintenance expense	99,631	101,819	296,048	294,154
Depreciation and amortization expense	62,760	59,193	185,219	174,748
Taxes, other than income, expense	56,850	52,662	165,032	153,198
Operating income	77,052	63,662	458,749	402,144
Miscellaneous income (expense)	(62)	1,243	334	804
Interest charges	18,394	18,677	56,437	57,481
Income (loss) from continuing operations before income taxes	58,596	46,228	402,646	345,467
Income tax expense (benefit)	22,082	15,867	149,623	126,090
Income from continuing operations		30,361	253,023	219,377
Income from discontinued operations, net of tax, before gain on disposal		0	0	0
Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			0
Net income (loss)	36,514	30,361	253,023	219,377
Pipeline and Storage Segment [Member]
Operating revenues [Abstract]
Operating revenues	117,283	113,855	339,207	314,424
Purchase Gas Cost [Abstract]
Purchased gas cost	1,251	(438)	2,331	(72)
Operation and maintenance expense	29,059	29,569	89,863	84,919
Depreciation and amortization expense	17,263	13,687	49,429	40,179
Taxes, other than income, expense	6,098	6,303	20,579	18,761
Operating income	63,612	64,734	177,005	170,637
Miscellaneous income (expense)	(227)	(125)	(784)	(894)
Interest charges	10,104	9,002	30,035	27,294
Income (loss) from continuing operations before income taxes	53,281	55,607	146,186	142,449
Income tax expense (benefit)	18,987	19,825	52,351	51,134
Income from continuing operations		35,782	93,835	91,315
Income from discontinued operations, net of tax, before gain on disposal		0	0	0
Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			0
Net income (loss)	34,294	35,782	93,835	91,315
Intersegment Elimination [Member]
Operating revenues [Abstract]
Operating revenues	(84,842)	(82,548)	(255,609)	(229,894)
Purchase Gas Cost [Abstract]
Purchased gas cost	(84,842)	(82,548)	(255,565)	(229,894)
Operation and maintenance expense	0	0	(44)	0
Depreciation and amortization expense	0	0	0	0
Taxes, other than income, expense	0	0	0	0
Operating income	0	0	0	0
Miscellaneous income (expense)	0	0	0	0
Interest charges	0	0	0	0
Income (loss) from continuing operations before income taxes	0	0	0	0
Income tax expense (benefit)	0	0	0	0
Income from continuing operations		0	0	0
Income from discontinued operations, net of tax, before gain on disposal		0	0	0
Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			0
Net income (loss)	$ 0	$ 0	$ 0	$ 0

CONDENSED CONSOLIDATED STATEME5

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) (PARENTHETICALS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Discontinued Operation, Tax Effect of Discontinued Operation		$ 3,414	$ 6,841	$ 3,495
Discontinued Operation, Tax Effect of Gain (Loss) from Disposal of Discontinued Operation	$ 0	$ 0	$ 10,215	$ 0
Natural Gas Marketing Segment [Member]
Discontinued Operation, Tax Effect of Discontinued Operation	$ 0

CONDENSED CONSOLIDATED STATEME6

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 70,808	$ 71,193	$ 360,568	$ 315,864
Other comprehensive income (loss), net of tax
Net unrealized holding gains (losses) on available-for-sale securities, net of tax	851	151	1,553	(1,496)
Schedule of Other Comprehensive Income (Loss), Cash Flow Hedges [Line Items]
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(18,556)	(21,145)	81,870	(67,407)
Total other comprehensive income (loss)	(17,705)	(20,994)	83,423	(68,903)
Total comprehensive income (loss)	53,103	50,199	443,991	246,961
Interest Rate Contract [Member]
Schedule of Other Comprehensive Income (Loss), Cash Flow Hedges [Line Items]
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(18,556)	(39,250)	76,888	(88,085)
Commodity Contract [Member]
Schedule of Other Comprehensive Income (Loss), Cash Flow Hedges [Line Items]
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	$ 0	$ 18,105	$ 4,982	$ 20,678

CONDENSED CONSOLIDATED STATEME7

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) (PARENTHETICALS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Other Comprehensive Income Loss Tax Portion Attributable To Parent Abstract
Unrealized holding gains (losses) on available-for-sale securities, tax	$ 490	$ 110	$ 893	$ (837)
Interest Rate Contract [Member]
Schedule of Other Comprehensive Income (Loss), Tax, Cash Flow Hedges [Line Items]
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	(10,667)	(22,561)	44,194	(50,631)
Commodity Contract [Member]
Schedule of Other Comprehensive Income (Loss), Tax, Cash Flow Hedges [Line Items]
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	$ 0	$ 11,575	$ 3,183	$ 13,220

CONDENSED CONSOLIDATED STATEME8

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash Flows From Operating Activities
Net income	$ 360,568	$ 315,864
Adjustments to reconcile net income to net cash provided by operating activities:
Charged to depreciation and amortization	234,833	216,670
Deferred income taxes	188,256	171,042
Gain on sale of discontinued operations	(12,931)	0
Discontinued cash flow hedging for natural gas marketing commodity contracts	(10,579)	0
Other	14,892	14,430
Net assets / liabilities from risk management activities	25,661	7,973
Net change in operating assets and liabilities	(55,139)	(96,033)
Net cash provided by operating activities	745,561	629,946
Cash Flows From Investing Activities
Capital expenditures	(812,148)	(789,688)
Acquisition	(86,128)	0
Proceeds from the sale of discontinued operations	140,253	0
Available-for-sale securities activities, net	(14,329)	558
Use tax refund	18,562	0
Other, net	6,435	5,731
Net cash used in investing activities	(747,355)	(783,399)
Cash Flows From Financing Activities
Net increase in short-term debt	(571,238)	212,539
Net proceeds from equity offering	98,755	98,660
Issuance of common stock through stock purchase and employee retirement plans	22,673	26,500
Proceeds from issuance of long-term debt, net of discount	884,911	0
Settlement of interest rate agreements	(36,996)	0
Repayments of long-term debt	(250,000)	0
Interest rate agreements cash collateral	25,670	(16,330)
Cash dividends paid	(143,075)	(130,363)
Other	(6,663)	0
Net cash provided by (used in) financing activities	24,037	191,006
Net increase (decrease) in cash and cash equivalents	22,243	37,553
Cash and cash equivalents at beginning of period	47,534	28,653
Cash and cash equivalents at end of period	$ 69,777	$ 66,206

Nature of Business

Nature of Business	9 Months Ended
	Jun. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business	Nature of Business Atmos Energy Corporation (“Atmos Energy” or the “Company”) is engaged in the regulated natural gas distribution and pipeline and storage businesses. Our regulated businesses are 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 approximately three million residential, commercial, public authority and industrial customers through our six natural gas distribution divisions, which at June 30, 2017 , covered service areas located in eight states. Our pipeline and storage business includes the transportation of natural gas to Texas and Louisiana distribution systems and the management of our underground storage facilities used to support Texas distribution businesses. Effective January 1, 2017, we completed the sale of all of the equity interests of Atmos Energy Marketing (AEM) to CenterPoint Energy Services, Inc., a subsidiary of CenterPoint Energy, Inc. (CES). Accordingly, AEM’s historical financial results are reflected in the Company’s condensed consolidated financial statements as discontinued operations, which required retrospective application to financial information for all periods presented. Refer to Note 6 for further information. Our discontinued natural gas marketing segment was primarily engaged in a nonregulated natural gas marketing business, conducted by AEM. This business provided natural gas management and transportation services to municipalities, regulated distribution companies, including certain divisions of Atmos Energy and third parties.

Unaudited Financial Information

Unaudited Financial Information	9 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Unaudited Financial Information	Unaudited Financial Information These consolidated interim-period financial statements have been prepared in accordance with accounting principles generally accepted in the United States on the same basis as those used for the Company’s audited consolidated financial statements for the fiscal year ended September 30, 2016 , which appear in Exhibit 99.1 to our Current Report on Form 8-K dated April 12, 2017 (the "Fiscal 2016 Financial Statements"). 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 our Fiscal 2016 Financial Statements. Because of seasonal and other factors, the results of operations for the nine -month period ended June 30, 2017 are not indicative of our results of operations for the full 2017 fiscal year, which ends September 30, 2017 . During the third quarter, we completed a State of Texas use tax audit that covered the period from October 2011 to March 2017, which resulted in a refund of $29.8 million . We concluded the appropriate regulatory treatment of this refund was to reduce rate base. We received $18.7 million during the third quarter, which has been included in cash flows from investing activities, and recorded an $11.1 million receivable as of June 30, 2017. On January 6, 2017, our Atmos Pipeline - Texas Division filed its statement of intent seeking $63.6 million , as adjusted in its rebuttal case, in additional annual operating income. On August 1, 2017, a final order was issued in our APT rate case resulting in a $13.0 million increase in annual operating income. No other 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 of our Fiscal 2016 Financial Statements. As discussed in Note 3 , due to the realignment of our reportable segments, prior periods' segment information has been recast in accordance with applicable accounting guidance. Additionally, as discussed in Note 6 , due to the sale of AEM, prior period amounts have been presented as discontinued operations. The segment realignment and the presentation of discontinued operations have not impacted our reported net income, financial position or cash flows. During the second quarter of fiscal 2017, we completed our annual goodwill impairment assessment. Based on the assessment performed, we determined that our goodwill was not impaired. In May 2014, the Financial Accounting Standards Board (FASB) issued a comprehensive new revenue recognition standard that will supersede virtually all existing revenue recognition guidance under generally accepted accounting principles in the United States. Under the new standard, an entity will recognize 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. In doing so, companies may need to use more judgment and make more estimates than under current guidance. The new guidance will become effective for us October 1, 2018 and can be applied either retrospectively to each period presented or as a cumulative-effect adjustment as of the date of adoption. As of June 30, 2017, we have substantially completed the evaluation of our sources of revenue and are currently assessing the effect that the new guidance will have on our financial position, results of operations, cash flows and business processes. The conclusion of our assessment is contingent, in part, upon the completion of deliberations currently in progress by our industry, notably in connection with efforts to produce an accounting guide intended to be developed by the American Institute of Certified Public Accountants (AICPA). In association with this undertaking, the AICPA formed a number of industry task forces, including a Power & Utilities (P&U) Task Force. Industry representatives and organizations, the largest auditing firms, the AICPA’s Revenue Recognition Working Group and its Financial Reporting Executive Committee have undertaken, and continue to undertake, consideration of several items relevant to our industry as further discussed below. Where applicable or necessary, the FASB’s Transition Resource Group (TRG) is also participating. Additionally, we are actively working with our peers in the rate-regulated natural gas industry and with the public accounting profession to conclude on the accounting treatment for several other issues that are not expected to be addressed by the P&U Task Force. Based on the progress of these deliberations to date, we currently do not believe the implementation of the new guidance will have a material effect on our financial position, results of operations, cash flows or business processes. We are currently still evaluating the transition method we will utilize to adopt the new guidance as well as the impact to our financial statement presentation and related disclosures. In May 2015, the FASB issued guidance removing the requirement to categorize within the fair value hierarchy all investments for which fair value is measured using the net asset value per share practical expedient. The guidance was effective for us on October 1, 2016, to be applied retrospectively. We measure certain pension plan assets using the net asset value per share practical expedient, which are disclosed on an annual basis in our Form 10-K. The adoption of the new standard should have no material impact on our results of operations, consolidated balance sheets or cash flows. 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. The guidance is effective for us beginning October 1, 2018; limited 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 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; early adoption is permitted. 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. As of June 30, 2017, we had begun the process of identifying and categorizing our lease contracts, evaluating our current business processes and identifying a lease software solution. We are currently evaluating the effect on our financial position, results of operations and cash flows. 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 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 beginning on October 1, 2019. We are currently evaluating the potential impact of this new guidance on our financial position, results of operations and cash flows. In January 2017, the FASB issued new guidance that simplifies the accounting for goodwill impairments by eliminating step 2 from the goodwill impairment test. Under the new guidance, if the carrying amount of a reporting unit exceeds its fair value, an impairment loss will be recognized in an amount equal to that excess, limited to the total amount of goodwill allocated to that reporting unit. The new standard will be effective for our fiscal 2021 goodwill impairment test; however, early adoption is permitted for goodwill impairment tests performed on testing dates after January 1, 2017. The adoption of the new standard will have no impact on our results of operations, consolidated balance sheets or cash flows. In March 2017, the FASB issued new guidance related to the income statement 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 income. The other components of net benefit cost will be presented outside of income from operations on the statement of income. In addition, 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 new guidance is effective for us in the fiscal year beginning on October 1, 2018 and for interim periods within that year. We are currently evaluating the potential impact of this new guidance on our financial position, results of operations and cash flows. Regulatory assets and liabilities Accounting principles generally accepted in the United States require cost-based, rate-regulated entities that meet certain criteria to reflect the authorized recovery of costs due to regulatory decisions in their financial statements. As a result, certain costs are permitted to be capitalized rather than expensed because they can be recovered through rates. We record certain costs as regulatory assets when future recovery through customer rates is considered probable. Regulatory liabilities are recorded when it is probable that revenues will be reduced for amounts that will be credited to customers through the ratemaking process. Substantially all of our regulatory assets are recorded as a component of deferred charges and other assets and substantially all of our regulatory liabilities are recorded as a component of deferred credits and other liabilities. Deferred gas costs are recorded either in other current assets or liabilities and the regulatory cost of removal obligation is reported separately. Significant regulatory assets and liabilities as of June 30, 2017 and September 30, 2016 included the following: June 30, September 30, (In thousands) Regulatory assets: Pension and postretirement benefit costs (1) $ 122,202 $ 132,348 Infrastructure mechanisms (2) 38,653 42,719 Deferred gas costs 16,405 45,184 Recoverable loss on reacquired debt 11,843 13,761 Deferred pipeline record collection costs 10,327 7,336 APT annual adjustment mechanism 4,973 7,171 Rate case costs 2,480 1,539 Other 9,949 13,565 $ 216,832 $ 263,623 Regulatory liabilities: Regulatory cost of removal obligations $ 492,404 $ 476,891 Deferred gas costs 16,753 20,180 Asset retirement obligations 13,404 13,404 Other 6,729 4,250 $ 529,290 $ 514,725 (1) Includes $11.5 million and $12.4 million of pension and postretirement expense deferred pursuant to regulatory authorization. (2) 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.

Segment Information

Segment Information	9 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
Segment Information	Segment Information Through November 30, 2016, our consolidated operations were managed and reviewed through three segments: • The regulated distribution segment , which included our regulated natural gas distribution and related sales operations. • The regulated pipeline segment , which included the pipeline and storage operations of our Atmos Pipeline-Texas division and, • The nonregulated segment , which included our nonregulated natural gas management, nonregulated natural gas transmission, storage and other services. As a result of the announced sale of Atmos Energy Marketing, we revised the information used by the chief operating decision maker to manage the Company, effective December 1, 2016. Accordingly, we have been managing and reviewing our consolidated operations through the following three reportable segments: • The distribution segment is primarily comprised of our regulated natural gas distribution and related sales operations in eight states and storage assets located in Kentucky and Tennessee, which are used solely to support our natural gas distribution operations in those states. These storage assets were formerly included in our nonregulated segment. • 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, which were formerly included in our nonregulated segment. • The natural gas marketing segment is comprised of our discontinued natural gas marketing business. Our determination of reportable segments considers the strategic operating units under which we manage sales of various products and services to customers in differing regulatory environments. Although our distribution segment operations are geographically dispersed, they are aggregated and reported as a single segment as each natural gas distribution division has similar economic characteristics. In addition, because the pipeline and storage operations of our Atmos Pipeline-Texas division and our natural gas transmission operations in Louisiana have similar economic characteristics, they have been aggregated and reported as a single segment. The accounting policies of the segments are the same as those described in the summary of significant accounting policies found in our Fiscal 2016 Financial Statements. We evaluate performance based on net income or loss of the respective operating segments. We allocate interest and pension expense to the pipeline and storage segment; however, there is no debt or pension liability recorded on the pipeline and storage segment balance sheet. All material intercompany transactions have been eliminated; however, we have not eliminated intercompany profits when such amounts are probable of recovery under the affiliates’ rate regulation process. Prior periods' segment information has been recast as required by applicable accounting guidance. The segment realignment has not impacted our reported consolidated revenues or net income. Income statements for the three and nine months ended June 30, 2017 and 2016 by segment are presented in the following tables: Three Months Ended June 30, 2017 Distribution Pipeline and Storage Natural Gas Marketing Eliminations Consolidated (In thousands) Operating revenues from external parties $ 493,738 $ 32,763 $ — $ — $ 526,501 Intersegment revenues 322 84,520 — (84,842 ) — Total operating revenues 494,060 117,283 — (84,842 ) 526,501 Purchased gas cost 197,767 1,251 — (84,842 ) 114,176 Operation and maintenance expense 99,631 29,059 — — 128,690 Depreciation and amortization expense 62,760 17,263 — — 80,023 Taxes, other than income 56,850 6,098 — — 62,948 Operating income 77,052 63,612 — — 140,664 Miscellaneous expense (62 ) (227 ) — — (289 ) Interest charges 18,394 10,104 — — 28,498 Income before income taxes 58,596 53,281 — — 111,877 Income tax expense 22,082 18,987 — — 41,069 Net income $ 36,514 $ 34,294 $ — $ — $ 70,808 Capital expenditures $ 205,780 $ 46,983 $ — $ — $ 252,763 Three Months Ended June 30, 2016 Distribution Pipeline and Storage Natural Gas Marketing Eliminations Consolidated (In thousands) Operating revenues from external parties $ 424,553 $ 31,659 $ — $ — $ 456,212 Intersegment revenues 352 82,196 — (82,548 ) — Total operating revenues 424,905 113,855 — (82,548 ) 456,212 Purchased gas cost 147,569 (438 ) — (82,548 ) 64,583 Operation and maintenance expense 101,819 29,569 — — 131,388 Depreciation and amortization expense 59,193 13,687 — — 72,880 Taxes, other than income 52,662 6,303 — — 58,965 Operating income 63,662 64,734 — — 128,396 Miscellaneous income (expense) 1,243 (125 ) — — 1,118 Interest charges 18,677 9,002 — — 27,679 Income from continuing operations before income taxes 46,228 55,607 — — 101,835 Income tax expense 15,867 19,825 — — 35,692 Income from continuing operations 30,361 35,782 — — 66,143 Income from discontinued operations, net of tax — — 5,050 — 5,050 Net income $ 30,361 $ 35,782 $ 5,050 $ — $ 71,193 Capital expenditures $ 187,470 $ 66,108 $ 106 $ — $ 253,684 Nine Months Ended June 30, 2017 Distribution Pipeline and Storage Natural Gas Marketing Eliminations Consolidated (In thousands) Operating revenues from external parties $ 2,210,221 $ 84,634 $ — $ — $ 2,294,855 Intersegment revenues 1,036 254,573 — (255,609 ) — Total operating revenues 2,211,257 339,207 — (255,609 ) 2,294,855 Purchased gas cost 1,106,209 2,331 — (255,565 ) 852,975 Operation and maintenance expense 296,048 89,863 — (44 ) 385,867 Depreciation and amortization expense 185,219 49,429 — — 234,648 Taxes, other than income 165,032 20,579 — — 185,611 Operating income 458,749 177,005 — — 635,754 Miscellaneous income (expense) 334 (784 ) — — (450 ) Interest charges 56,437 30,035 — — 86,472 Income from continuing operations before income taxes 402,646 146,186 — — 548,832 Income tax expense 149,623 52,351 — — 201,974 Income from continuing operations 253,023 93,835 — — 346,858 Income from discontinued operations, net of tax — — 10,994 — 10,994 Gain on sale of discontinued operations, net of tax — — 2,716 — 2,716 Net income $ 253,023 $ 93,835 $ 13,710 $ — $ 360,568 Capital expenditures $ 636,449 $ 175,699 $ — $ — $ 812,148 Nine Months Ended June 30, 2016 Distribution Pipeline and Storage Natural Gas Marketing Eliminations Consolidated (In thousands) Operating revenues from external parties $ 1,935,421 $ 85,584 $ — $ — $ 2,021,005 Intersegment revenues 1,054 228,840 — (229,894 ) — Total operating revenues 1,936,475 314,424 — (229,894 ) 2,021,005 Purchased gas cost 912,231 (72 ) — (229,894 ) 682,265 Operation and maintenance expense 294,154 84,919 — — 379,073 Depreciation and amortization expense 174,748 40,179 — — 214,927 Taxes, other than income 153,198 18,761 — — 171,959 Operating income 402,144 170,637 — — 572,781 Miscellaneous income (expense) 804 (894 ) — — (90 ) Interest charges 57,481 27,294 — — 84,775 Income from continuing operations before income taxes 345,467 142,449 — — 487,916 Income tax expense 126,090 51,134 — — 177,224 Income from continuing operations 219,377 91,315 — — 310,692 Income from discontinued operations, net of tax — — 5,172 — 5,172 Net income $ 219,377 $ 91,315 $ 5,172 $ — $ 315,864 Capital expenditures $ 528,063 $ 261,446 $ 179 $ — $ 789,688 Balance sheet information at June 30, 2017 and September 30, 2016 by segment is presented in the following tables: June 30, 2017 Distribution Pipeline and Storage Natural Gas Marketing Eliminations Consolidated (In thousands) ASSETS Property, plant and equipment, net $ 6,678,875 $ 2,245,506 $ — $ — $ 8,924,381 Investment in subsidiaries 798,994 13,851 — (812,845 ) — Current assets Cash and cash equivalents 69,777 — — — 69,777 Other current assets 437,700 29,265 — (2,360 ) 464,605 Intercompany receivables 983,866 — — (983,866 ) — Total current assets 1,491,343 29,265 — (986,226 ) 534,382 Goodwill 586,661 143,012 — — 729,673 Deferred charges and other assets 280,240 30,099 — — 310,339 $ 9,836,113 $ 2,461,733 $ — $ (1,799,071 ) $ 10,498,775 CAPITALIZATION AND LIABILITIES Shareholders’ equity $ 3,901,710 $ 812,845 $ — $ (812,845 ) $ 3,901,710 Long-term debt 3,066,734 — — — 3,066,734 Total capitalization 6,968,444 812,845 — (812,845 ) 6,968,444 Current liabilities Short-term debt 258,573 — — — 258,573 Other current liabilities 451,026 38,420 — (2,360 ) 487,086 Intercompany payables — 983,866 — (983,866 ) — Total current liabilities 709,599 1,022,286 — (986,226 ) 745,659 Deferred income taxes 1,251,528 602,036 — — 1,853,564 Regulatory cost of removal obligation 432,531 24,529 — — 457,060 Pension and postretirement liabilities 304,919 — — — 304,919 Deferred credits and other liabilities 169,092 37 — — 169,129 $ 9,836,113 $ 2,461,733 $ — $ (1,799,071 ) $ 10,498,775 September 30, 2016 Distribution Pipeline and Storage Natural Gas Marketing Eliminations Consolidated (In thousands) ASSETS Property, plant and equipment, net $ 6,208,465 $ 2,060,141 $ — $ — $ 8,268,606 Investment in subsidiaries 768,415 13,854 — (782,269 ) — Current assets Cash and cash equivalents 22,117 — 25,417 — 47,534 Current assets of disposal group classified as held for sale — — 162,508 (11,391 ) 151,117 Other current assets 489,963 39,078 5 (46,011 ) 483,035 Intercompany receivables 971,665 — — (971,665 ) — Total current assets 1,483,745 39,078 187,930 (1,029,067 ) 681,686 Goodwill 583,950 143,012 — — 726,962 Noncurrent assets of disposal group classified as held for sale — — 28,785 (169 ) 28,616 Deferred charges and other assets 277,240 27,779 — — 305,019 $ 9,321,815 $ 2,283,864 $ 216,715 $ (1,811,505 ) $ 10,010,889 CAPITALIZATION AND LIABILITIES Shareholders’ equity $ 3,463,059 $ 715,672 $ 66,597 $ (782,269 ) $ 3,463,059 Long-term debt 2,188,779 — — — 2,188,779 Total capitalization 5,651,838 715,672 66,597 (782,269 ) 5,651,838 Current liabilities Current maturities of long-term debt 250,000 — — — 250,000 Short-term debt 829,811 — 35,000 (35,000 ) 829,811 Current liabilities of the disposal group classified as held for sale — — 81,908 (9,008 ) 72,900 Other current liabilities 605,790 39,911 3,263 (13,394 ) 635,570 Intercompany payables — 957,526 14,139 (971,665 ) — Total current liabilities 1,685,601 997,437 134,310 (1,029,067 ) 1,788,281 Deferred income taxes 1,055,348 543,390 4,318 — 1,603,056 Regulatory cost of removal obligation 397,162 27,119 — — 424,281 Pension and postretirement liabilities 297,743 — — — 297,743 Noncurrent liabilities of disposal group classified as held for sale — — 316 — 316 Deferred credits and other liabilities 234,123 246 11,174 (169 ) 245,374 $ 9,321,815 $ 2,283,864 $ 216,715 $ (1,811,505 ) $ 10,010,889

Earnings Per Share

Earnings Per Share	9 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share We use the two-class method of computing earnings per share because we have participating securities in the form of non-vested restricted stock units with a nonforfeitable right to dividend equivalents, for which vesting is predicated solely on the passage of time. The calculation of earnings per share using the two-class method excludes income attributable to these participating securities from the numerator and excludes the dilutive impact of those shares from the denominator. Basic and diluted earnings per share for the three and nine months ended June 30, 2017 and 2016 are calculated as follows: Three Months Ended Nine Months Ended 2017 2016 2017 2016 (In thousands, except per share amounts) Basic and Diluted Earnings Per Share from continuing operations Income from continuing operations $ 70,808 $ 66,143 $ 346,858 $ 310,692 Less: Income from continuing operations allocated to participating securities 75 100 424 488 Income from continuing operations available to common shareholders $ 70,733 $ 66,043 $ 346,434 $ 310,204 Basic and diluted weighted average shares outstanding 106,364 103,750 105,862 103,137 Income from continuing operations per share — Basic and Diluted $ 0.67 $ 0.64 $ 3.27 $ 3.01 Basic and Diluted Earnings Per Share from discontinued operations Income from discontinued operations $ — $ 5,050 $ 13,710 $ 5,172 Less: Income from discontinued operations allocated to participating securities — 6 15 4 Income from discontinued operations available to common shareholders $ — $ 5,044 $ 13,695 $ 5,168 Basic and diluted weighted average shares outstanding 106,364 103,750 105,862 103,137 Income from discontinued operations per share — Basic and Diluted $ — $ 0.05 $ 0.13 $ 0.05 Net income per share — Basic and Diluted $ 0.67 $ 0.69 $ 3.40 $ 3.06

Debt

Debt	9 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Debt	Debt The nature and terms of our debt instruments and credit facilities are described in detail in Note 5 in our Fiscal 2016 Financial Statements. Except as noted below, there were no material changes in the terms of our debt instruments during the nine months ended June 30, 2017 . Long-term debt at June 30, 2017 and September 30, 2016 consisted of the following: June 30, 2017 September 30, 2016 (In thousands) Unsecured 6.35% Senior Notes, due June 2017 $ — $ 250,000 Unsecured 8.50% Senior Notes, due 2019 450,000 450,000 Unsecured 3.00% Senior Notes, due 2027 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 750,000 500,000 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 2019 125,000 — Total long-term debt 3,085,000 2,460,000 Less: Original issue (premium) discount on unsecured senior notes and debentures (4,370 ) 4,270 Debt issuance cost 22,636 16,951 Current maturities — 250,000 $ 3,066,734 $ 2,188,779 On June 8, 2017, we completed a public offering of $500 million of 3.00% senior notes due 2027 and $250 million of 4.125% senior notes due 2044. The effective rate of these notes is 3.12% and 4.40% , after giving effect to the offering costs and the settlement of the associated forward starting interest rate swaps. The net proceeds (excluding the loss on the settlement of the interest rate swaps of $37 million ) of approximately $753 million were used to repay our $250 million 6.35% senior unsecured notes at maturity on June 15, 2017 and for general corporate purposes, including the repayment of working capital borrowings pursuant to our commercial paper program. On September 22, 2016, we entered into a three year, $200 million multi-draw floating-rate term loan agreement with a syndicate of three lenders. Borrowings under the term loan may be made in increments of $1.0 million or higher, may be repaid at any time during the loan period and will bear interest at a rate dependent upon our credit ratings at the time of such borrowing and based, at our election, on a base rate or LIBOR for the applicable interest period. The term loan was used to repay short-term debt and for working capital, capital expenditures and other general corporate purposes. At June 30, 2017 , there was $125.0 million outstanding under the term loan. We utilize short-term debt to fund ongoing working capital needs, such as our seasonal requirements for gas supply, general corporate liquidity and capital expenditures. Our short-term borrowing requirements are affected primarily by 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. We currently finance our short-term borrowing requirements 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 September 25, 2021. 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 . This facility was amended in October 2016 to increase the total availability from $1.25 billion . At June 30, 2017 and September 30, 2016 a total of $258.6 million and $829.8 million was outstanding under our commercial paper program. Additionally, we have a $25 million unsecured facility, which was renewed on April 1, 2017 , and a $10 million unsecured revolving credit facility, which is used primarily to issue letters of credit. At June 30, 2017 , 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 unsecured revolving facility to $4.1 million . The availability of funds under these credit facilities is subject to conditions specified in the respective credit agreements, all of which we currently satisfy. These conditions include our compliance with financial covenants and the continued accuracy of representations and warranties contained in these agreements. We are required by the financial covenants in each of these facilities to maintain, at the end of each fiscal quarter, a ratio of total debt to total capitalization of no greater than 70 percent . At June 30, 2017 , our total-debt-to-total-capitalization ratio, as defined in the agreements, was 47 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 is not paid at maturity. We were in compliance with all of our debt covenants as of June 30, 2017 . 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. AEM had one uncommitted $25 million 364-day bilateral credit facility that was scheduled to expire on July 31, 2017 and one committed $15 million 364-day bilateral credit facility that was scheduled to expire on September 30, 2017. In connection with the sale of AEM discussed in Note 6 , both facilities were terminated on January 3, 2017.

Divestitures and Acquisitions

Divestitures and Acquisitions	9 Months Ended
	Jun. 30, 2017
Divestitures and Acquisitions [Abstract]
Divestitures and Acquisitions [Text Block]	Divestitures and Acquisitions Divestiture of Atmos Energy Marketing (AEM) On October 29, 2016, we entered into a Membership Interest Purchase Agreement (the Agreement) with CenterPoint Energy Services, Inc., a subsidiary of CenterPoint Energy, Inc. (CES) to sell all of the equity interests of AEM. The transaction closed on January 3, 2017, with an effective date of January 1, 2017 . CES paid a cash purchase price of $38.3 million plus working capital of $109.0 million for total cash consideration of $147.3 million . Of this amount, $7.0 million was placed into escrow and will be paid to the Company within 24 months of the closing date, net of any indemnification claims agreed upon between the two companies. We recognized a net gain of $0.03 per diluted share on the sale in the second quarter of fiscal 2017 and completed the working capital true–up during the third quarter of fiscal 2017. The operating results of our natural gas marketing reportable segment have been reported on the condensed consolidated statements of income as income from discontinued operations, net of income tax. Accordingly, expenses related to allocable general corporate overhead and interest expense are not included in these results. The decision to report this segment as a discontinued operation was predicated, in part, on the following qualitative and quantitative factors: 1) the disposal resulted in the company becoming a fully regulated entity; 2) the fact that an entire reportable segment was disposed of and 3) the fact the disposed segment represented in excess of 30 percent of consolidated revenues over the last five fiscal years. The tables below set forth selected financial and operational information related to assets, liabilities and operating results related to discontinued operations. Operating expenses include operation and maintenance expense, provision for doubtful accounts, depreciation and amortization expense and taxes, other than income. Additionally, assets and liabilities related to our natural gas marketing operations are classified as “held for sale” on our consolidated balance sheet at September 30, 2016 . Prior period revenues and expenses associated with these assets have been reclassified into discontinued operations. This reclassification had no impact on previously reported consolidated net income. The following tables present statement of income data related to discontinued operations: Three Months Ended 2017 2016 (In thousands) Operating revenues $ — $ 200,213 Purchased gas cost — 184,398 Operating expenses — 7,047 Operating income — 8,768 Other nonoperating expense — (304 ) Income from discontinued operations before income taxes — 8,464 Income tax expense — 3,414 Net income from discontinued operations $ — $ 5,050 Nine Months Ended 2017 2016 (In thousands) Operating revenues $ 303,474 $ 728,989 Purchased gas cost 277,554 698,445 Operating expenses 7,874 19,940 Operating income 18,046 10,604 Other nonoperating expense (211 ) (1,937 ) Income from discontinued operations before income taxes 17,835 8,667 Income tax expense 6,841 3,495 Income from discontinued operations 10,994 5,172 Gain on sale from discontinued operations, net of tax ($10,215 and $0) 2,716 — Net income from discontinued operations $ 13,710 $ 5,172 The following table presents a reconciliation of the carrying amounts of major classes of assets and liabilities of our natural gas marketing's operations to total assets and liabilities classified as held for sale: June 30, 2017 September 30, 2016 (In thousands) Assets: Net property, plant and equipment $ — $ 11,905 Accounts receivable — 93,551 Gas stored underground — 54,246 Other current assets — 14,711 Goodwill — 16,445 Deferred charges and other assets — 435 Total assets of the disposal group classified as held for sale in the statement of financial position (1) — 191,293 Cash — 25,417 Other assets — 5 Total assets of disposal group in the statement of financial position $ — $ 216,715 Liabilities: Accounts payable and accrued liabilities $ — $ 72,268 Other current liabilities — 9,640 Deferred credits and other — 316 Total liabilities of the disposal group classified as held for sale in the statement of financial position (1) — 82,224 Intercompany note payable — 35,000 Tax liabilities — 15,471 Intercompany payables — 14,139 Other liabilities — 3,284 Total liabilities of disposal group in the statement of financial position $ — $ 150,118 (1) Amounts in the comparative period are classified as current and long term in the statement of financial position. The following table presents statement of cash flow data related to discontinued operations: Nine Months Ended 2017 2016 (In thousands) Depreciation and amortization expense $ 185 $ 1,743 Capital expenditures $ — $ 179 Noncash gain (loss) in commodity contract cash flow hedges $ 18,744 $ (33,898 ) Acquisition of EnLink Pipeline On December 20, 2016 , we executed a purchase and sale agreement to acquire the general partnership and limited partnership interests in EnLink North Texas Pipeline, LP (EnLink Pipeline) from EnLink Energy GP, LLC and EnLink Midstream Operating, LP for a cash purchase price of $85 million , plus working capital of $1.1 million . EnLink Pipeline's primary asset was a 140–mile natural gas pipeline located on the north side of the Dallas–Fort Worth Metroplex. The $85 million purchase price has been allocated, based on fair value using observable market inputs, to the net book value of the acquired pipeline.

Shareholders' Equity

Shareholders' Equity	9 Months Ended
	Jun. 30, 2017
Equity [Abstract]
Shareholders' Equity	Shareholders' Equity Shelf Registration and At-the-Market Equity Sales Program On March 28, 2016, we filed a registration statement with the Securities and Exchange Commission (SEC) that originally permitted us to issue, from time to time, up to $2.5 billion in common stock and/or debt securities. We also filed a prospectus supplement under the registration statement relating to an at-the-market (ATM) equity distribution program under which we may issue and sell, shares of our common stock, up to an aggregate offering price of $200 million . During the nine months ended June 30, 2017 , we sold 1,303,494 shares of common stock under our existing ATM program for $100 million and received net proceeds of $98.8 million . At June 30, 2017 , approximately $1.6 billion of securities remained available for issuance under the shelf registration statement and substantially all shares have been issued under our ATM program. Accumulated Other Comprehensive Income (Loss) We record deferred gains (losses) in AOCI related to available-for-sale securities, interest rate cash flow hedges and commodity contract cash flow hedges. Deferred gains (losses) for our available-for-sale securities and commodity contract cash flow hedges 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 Interest Rate Agreement Cash Flow Hedges Commodity Contracts Cash Flow Hedges Total (In thousands) September 30, 2016 $ 4,484 $ (187,524 ) $ (4,982 ) $ (188,022 ) Other comprehensive income before reclassifications 1,485 76,602 9,847 87,934 Amounts reclassified from accumulated other comprehensive income 68 286 (4,865 ) (4,511 ) Net current-period other comprehensive income 1,553 76,888 4,982 83,423 June 30, 2017 $ 6,037 $ (110,636 ) $ — $ (104,599 ) Available- for-Sale Securities Interest Rate Agreement Cash Flow Hedges Commodity Contracts Cash Flow Hedges Total (In thousands) September 30, 2015 $ 4,949 $ (88,842 ) $ (25,437 ) $ (109,330 ) Other comprehensive loss before reclassifications (1,417 ) (88,345 ) (8,612 ) (98,374 ) Amounts reclassified from accumulated other comprehensive income (79 ) 260 29,290 29,471 Net current-period other comprehensive income (loss) (1,496 ) (88,085 ) 20,678 (68,903 ) June 30, 2016 $ 3,453 $ (176,927 ) $ (4,759 ) $ (178,233 ) The following tables detail reclassifications out of AOCI for the three and nine months ended June 30, 2017 and 2016 . Amounts in parentheses below indicate decreases to net income in the statement of income: Three Months Ended June 30, 2017 Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement of Income (In thousands) Cash flow hedges Interest rate agreements $ (177 ) Interest charges Commodity contracts — Purchased gas cost (177 ) Total before tax 64 Tax benefit Total reclassifications $ (113 ) Net of tax Three Months Ended June 30, 2016 Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement of Income (In thousands) Cash flow hedges Interest rate agreements $ (137 ) Interest charges Commodity contracts (12,347 ) Purchased gas cost (1) (12,484 ) Total before tax 4,865 Tax benefit Total reclassifications $ (7,619 ) Net of tax Nine Months Ended June 30, 2017 Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement of Income (In thousands) Available-for-sale securities $ (107 ) Operation and maintenance expense (107 ) Total before tax 39 Tax benefit $ (68 ) Net of tax Cash flow hedges Interest rate agreements $ (450 ) Interest charges Commodity contracts 7,976 Purchased gas cost (1) 7,526 Total before tax (2,947 ) Tax expense $ 4,579 Net of tax Total reclassifications $ 4,511 Net of tax Nine Months Ended June 30, 2016 Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement of Income (In thousands) Available-for-sale securities $ 124 Operation and maintenance expense 124 Total before tax (45 ) Tax expense $ 79 Net of tax Cash flow hedges Interest rate agreements $ (410 ) Interest charges Commodity contracts (48,015 ) Purchased gas cost (1) (48,425 ) Total before tax 18,875 Tax benefit $ (29,550 ) Net of tax Total reclassifications $ (29,471 ) Net of tax (1) Amounts are presented as part of income from discontinued operations on the condensed consolidated statements of income.

Interim Pension and Other Postr

Interim Pension and Other Postretirement Benefit Plan Information	9 Months Ended
	Jun. 30, 2017
General Discussion of Pension and Other Postretirement Benefits [Abstract]
Interim Pension and Postretirement Benefit Plans	Interim Pension and Other Postretirement Benefit Plan Information The components of our net periodic pension cost for our pension and other postretirement benefit plans for the three and nine months ended June 30, 2017 and 2016 are presented in the following table. Most of these costs are recoverable through our tariff rates; however, a portion of these costs is capitalized into our rate base. The remaining costs are recorded as a component of operation and maintenance expense. Three Months Ended June 30 Pension Benefits Other Benefits 2017 2016 2017 2016 (In thousands) Components of net periodic pension cost: Service cost $ 5,216 $ 4,698 $ 3,109 $ 2,705 Interest cost 6,296 7,095 2,669 3,106 Expected return on assets (6,993 ) (6,881 ) (1,796 ) (1,566 ) Amortization of transition obligation — — — 21 Amortization of prior service credit (57 ) (57 ) (411 ) (411 ) Amortization of actuarial (gain) loss 4,248 3,319 (706 ) (541 ) Net periodic pension cost $ 8,710 $ 8,174 $ 2,865 $ 3,314 Nine Months Ended June 30 Pension Benefits Other Benefits 2017 2016 2017 2016 (In thousands) Components of net periodic pension cost: Service cost $ 15,649 $ 14,093 $ 9,327 $ 8,117 Interest cost 18,890 21,284 8,009 9,318 Expected return on assets (20,981 ) (20,642 ) (5,389 ) (4,698 ) Amortization of transition obligation — — — 62 Amortization of prior service credit (173 ) (170 ) (1,233 ) (1,233 ) Amortization of actuarial (gain) loss 12,746 9,959 (2,120 ) (1,625 ) Net periodic pension cost $ 26,131 $ 24,524 $ 8,594 $ 9,941 The assumptions used to develop our net periodic pension cost for the three and nine months ended June 30, 2017 and 2016 are as follows: Pension Benefits Other Benefits 2017 2016 2017 2016 Discount rate 3.73% 4.55% 3.73% 4.55% Rate of compensation increase 3.50% 3.50% N/A N/A Expected return on plan assets 7.00% 7.00% 4.45% 4.45% The discount rate used to compute the present value of a plan’s liabilities generally is based on rates of high-grade corporate bonds with maturities similar to the average period over which the benefits will be paid. Generally, our funding policy has been to contribute annually an amount in accordance with the requirements of the Employee Retirement Income Security Act of 1974. In accordance with the Pension Protection Act of 2006 (PPA), we determined the funded status of our plan as of January 1, 2017. Based on that determination, we are not required to make a minimum contribution to our defined benefit plan during fiscal 2017; however, we made a voluntary contribution of $5.0 million during the third quarter of fiscal 2017 . We contributed $9.9 million to our other post-retirement benefit plans during the nine months ended June 30, 2017 . We expect to contribute a total of between $10 million and $20 million to these plans during fiscal 2017 .

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Litigation and Environmental Matters With respect to the specific litigation and environmental-related matters or claims that were disclosed in Note 11 of our Fiscal 2016 Financial Statements, there were no material changes in the status of such litigation and environmental-related matters or claims during the nine months ended June 30, 2017 . We are a party to various 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. At June 30, 2017 , we were committed to purchase 53.2 Bcf within one year, 37.6 Bcf within two to three years and 0.4 Bcf beyond three years under indexed contracts. Regulatory Matters Various regulatory agencies, including the SEC and the Commodities Futures Trading Commission, continue to adopt regulations implementing many of the provisions of the Dodd-Frank Act of 2010. We continue to enact new procedures and modify existing business practices and contractual arrangements to comply with such regulations. Additional rulemakings are pending which we believe will result in new reporting and disclosure obligations. The costs associated with hedging certain risks inherent in our business may be further increased when these expected additional regulations are adopted. As of June 30, 2017 , formula rate mechanisms were pending regulatory approval in our Louisiana service area, infrastructure mechanisms were pending regulatory approval in our Mississippi and Virginia service areas and rate cases were pending regulatory approval in our Colorado service area and Texas service area related to APT. These regulatory proceedings are discussed in further detail below in Management’s Discussion and Analysis — Recent Ratemaking Developments .

Financial Instruments

Financial Instruments	9 Months Ended
	Jun. 30, 2017
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 of our Fiscal 2016 Financial Statements. During the nine months ended June 30, 2017 , except for the change in the scope of our natural gas marketing commodity risk management activities as a result of the sale of AEM, 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. Regulated 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 2016 - 2017 heating season (generally October through March), in the jurisdictions where we are permitted to utilize financial instruments, we hedged approximately 27 percent , or 16.2 Bcf of the winter flowing gas requirements. We have not designated these financial instruments as hedges for accounting purposes. Natural Gas Marketing Commodity Risk Management Activities Our natural gas marketing segment was exposed to risks associated with changes in the market price of natural gas through the purchase, sale and delivery of natural gas to its customers at competitive prices. Through December 31, 2016, we managed our exposure to such risks through a combination of physical storage and financial instruments, including futures, over-the-counter and exchange-traded options and swap contracts with counterparties. Effective January 1, 2017, as a result of the sale of AEM, these activities were discontinued. Due to the sale of AEM, we determined that the cash flows associated with our natural gas marketing commodity cash flow hedges were no longer probable of occurring; therefore, we discontinued hedge accounting as of December 31, 2016. As a result, we reclassified the gain in accumulated other comprehensive income associated with the commodity contracts into earnings as a reduction of purchased gas cost and recognized a pre-tax gain of $10.6 million , which is included in income from discontinued operations on the condensed consolidated statement of income for the three months ended December 31, 2016. 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 June 30, 2017 , 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 June 30, 2017 , we had $41.5 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 income statements. As of June 30, 2017 , our financial instruments were comprised of both long and short commodity positions. A long position is a contract to purchase the commodity, while a short position is a contract to sell the commodity. As of June 30, 2017 , we had 18,833 MMcf of net short commodity contracts outstanding. These contracts have not been designated as hedges. Financial Instruments on the Balance Sheet The following tables present the fair value and balance sheet classification of our financial instruments as of June 30, 2017 and September 30, 2016 . 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 the counterparties. Balance Sheet Location Assets Liabilities (In thousands) June 30, 2017 Designated As Hedges: Interest rate contracts Deferred credits and other liabilities — (108,860 ) Total — (108,860 ) Not Designated As Hedges: Commodity contracts Other current assets / Other current liabilities 2,960 (230 ) Commodity contracts Deferred charges and other assets / Deferred credits and other liabilities 268 (282 ) Total 3,228 (512 ) Gross Financial Instruments 3,228 (109,372 ) Gross Amounts Offset on Consolidated Balance Sheet: Contract netting — — Net Financial Instruments 3,228 (109,372 ) Cash collateral — — Net Assets/Liabilities from Risk Management Activities $ 3,228 $ (109,372 ) Balance Sheet Location Assets Liabilities (In thousands) September 30, 2016 Designated As Hedges: Commodity contracts Other current assets / Other current liabilities $ 6,612 $ (21,903 ) Interest rate contracts Other current assets / — (68,481 ) Commodity contracts Deferred charges and other assets / Deferred credits and other liabilities 2,178 (3,779 ) Interest rate contracts Deferred charges and other assets / Deferred credits and other liabilities — (198,008 ) Total 8,790 (292,171 ) Not Designated As Hedges: Commodity contracts Other current assets / Other current liabilities 21,186 (18,812 ) Commodity contracts Deferred charges and other assets / Deferred credits and other liabilities 14,165 (12,701 ) Total 35,351 (31,513 ) Gross Financial Instruments 44,141 (323,684 ) Gross Amounts Offset on Consolidated Balance Sheet: Contract netting (39,290 ) 39,290 Net Financial Instruments 4,851 (284,394 ) Cash collateral 6,775 43,575 Net Assets/Liabilities from Risk Management Activities $ 11,626 $ (240,819 ) Impact of Financial Instruments on the Income Statement Hedge ineffectiveness for our natural gas marketing segment was recorded as a component of purchased gas cost, which is included in discontinued operations on the condensed consolidated statements of income, and primarily results from differences in the location and timing of the derivative instrument and the hedged item. For the three months ended June 30, 2016 , we recognized a gain arising from fair value and cash flow hedge ineffectiveness of $13.6 million . For the nine months ended June 30, 2017 and 2016 , we recognized gains arising from fair value and cash flow hedge ineffectiveness of $3.4 million and $18.1 million . Additional information regarding ineffectiveness recognized in the income statement is included in the tables below. Fair Value Hedges The impact of our natural gas marketing segment commodity contracts designated as fair value hedges and the related hedged item on the results of discontinued operations on our condensed consolidated income statement for the three and nine months ended June 30, 2017 and 2016 is presented below. Three Months Ended Nine Months Ended 2017 2016 2017 2016 (In thousands) Commodity contracts $ — $ (22,146 ) $ (9,567 ) $ (11,808 ) Fair value adjustment for natural gas inventory designated as the hedged item — 35,630 12,858 29,852 Total decrease in purchased gas cost reflected in income from discontinued operations $ — $ 13,484 $ 3,291 $ 18,044 The decrease in purchased gas cost reflected in income from discontinued operations is comprised of the following: Basis ineffectiveness $ — $ (684 ) $ (597 ) $ (1,490 ) Timing ineffectiveness — 14,168 3,888 19,534 $ — $ 13,484 $ 3,291 $ 18,044 Basis ineffectiveness arises from natural gas market price differences between the locations of the hedged inventory and the delivery location specified in the hedge instruments. Timing ineffectiveness arises due to changes in the difference between the spot price and the futures price, as well as the difference between the timing of the settlement of the futures and the valuation of the underlying physical commodity. Cash Flow Hedges The impact of our interest rate and natural gas marketing segment cash flow hedges on our condensed consolidated income statements for the three and nine months ended June 30, 2017 and 2016 is presented below. Three Months Ended Nine Months Ended 2017 2016 2017 2016 (In thousands) Loss reclassified from AOCI for effective portion of natural gas marketing commodity contracts $ — $ (12,347 ) $ (2,612 ) $ (48,015 ) Gain arising from ineffective portion of natural gas marketing commodity contracts — 66 111 84 Gain on discontinuance of cash flow hedging of natural gas marketing commodity contracts reclassified from AOCI — — 10,579 — Total impact on purchased gas cost reflected in income from discontinued operations — (12,281 ) 8,078 (47,931 ) Net loss on settled interest rate agreements reclassified from AOCI into interest expense (177 ) (137 ) (450 ) (410 ) Total Impact from Cash Flow Hedges $ (177 ) $ (12,418 ) $ 7,628 $ (48,341 ) The following table summarizes the gains and losses arising from hedging transactions that were recognized as a component of other comprehensive income (loss), net of taxes, for the three and nine months ended June 30, 2017 and 2016 . The amounts included in the table below exclude gains and losses arising from ineffectiveness because those amounts are immediately recognized in the income statement as incurred. Three Months Ended Nine Months Ended 2017 2016 2017 2016 (In thousands) Increase (decrease) in fair value: Interest rate agreements $ (18,669 ) $ (39,337 ) $ 76,602 $ (88,345 ) Forward commodity contracts — 10,573 9,847 (8,612 ) Recognition of (gains) losses in earnings due to settlements: Interest rate agreements 113 87 286 260 Forward commodity contracts — 7,532 (4,865 ) 29,290 Total other comprehensive income (loss) from hedging, net of tax (1) $ (18,556 ) $ (21,145 ) $ 81,870 $ (67,407 ) (1) Utilizing an income tax rate ranging from 37 percent to 39 percent based on the effective rates in each taxing jurisdiction. 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, while deferred gains (losses) associated with natural gas marketing segment commodity contracts were recognized in earnings upon settlement. The following amounts, net of deferred taxes, represent the expected recognition in earnings of the deferred losses recorded in AOCI associated with our financial instruments, based upon the fair values of these financial instruments as of June 30, 2017 . 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 $ (1,509 ) Thereafter (40,001 ) Total (1) $ (41,510 ) (1) Utilizing an income tax rate of 37 percent . Financial Instruments Not Designated as Hedges The impact of the natural gas marketing segment's financial instruments that had not been designated as hedges on our condensed consolidated income statements for the three months ended June 30, 2016 was a decrease in purchased gas cost of $1.9 million , which is included in discontinued operations on the condensed consolidated statements of income. For the nine months ended June 30, 2017 and 2016 purchased gas cost (increased) decreased by $6.8 million and $(2.8) million . 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 income as a component of purchased gas cost when the related costs are recovered through our rates and recognized in revenue. Accordingly, the impact of these financial instruments is excluded from this presentation.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Jun. 30, 2017
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 of our Fiscal 2016 Financial Statements. During the nine months ended June 30, 2017 , 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 of our Fiscal 2016 Financial Statements. Quantitative Disclosures Financial Instruments The classification of our fair value measurements requires judgment regarding the degree to which market data is observable or corroborated by observable market data. Authoritative accounting literature establishes a fair value hierarchy that prioritizes the inputs used to measure fair value based on observable and unobservable data. The hierarchy categorizes the inputs into three levels, with the highest priority given to unadjusted quoted prices in active markets for identical assets and liabilities (Level 1), with the lowest priority given to unobservable inputs (Level 3). The following tables summarize, by level within the fair value hierarchy, our assets and liabilities that were accounted for at fair value on a recurring basis as of June 30, 2017 and September 30, 2016 . Assets and liabilities are categorized in their entirety based on the lowest level of input that is significant to the fair value measurement. Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) (1) Significant Other Unobservable Inputs (Level 3) Netting and Cash Collateral June 30, 2017 (In thousands) Assets: Financial instruments $ — $ 3,228 $ — $ — $ 3,228 Available-for-sale securities Registered investment companies 39,406 — — — 39,406 Bond mutual funds 15,892 — — — 15,892 Bonds — 31,429 — — 31,429 Money market funds — 2,884 — — 2,884 Total available-for-sale securities 55,298 34,313 — — 89,611 Total assets $ 55,298 $ 37,541 $ — $ — $ 92,839 Liabilities: Financial instruments $ — $ 109,372 $ — $ — $ 109,372 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) (1) Significant Other Unobservable Inputs (Level 3) Netting and Cash Collateral (2) September 30, 2016 (In thousands) Assets: Financial instruments $ — $ 44,141 $ — $ (32,515 ) $ 11,626 Hedged portion of gas stored underground 52,578 — — — 52,578 Available-for-sale securities Registered investment companies 38,677 — — — 38,677 Bonds — 31,394 — — 31,394 Money market funds — 2,630 — — 2,630 Total available-for-sale securities 38,677 34,024 — — 72,701 Total assets $ 91,255 $ 78,165 $ — $ (32,515 ) $ 136,905 Liabilities: Financial instruments $ — $ 323,684 $ — $ (82,865 ) $ 240,819 (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 which are valued at cost. (2) This column reflects adjustments to our gross financial instrument assets and liabilities to reflect netting permitted under our master netting agreements and the relevant authoritative accounting literature. As of September 30, 2016 , we had $50.4 million of cash held in margin accounts to collateralize certain financial instruments. Of this amount, $43.6 million was used to offset current and noncurrent risk management liabilities under master netting arrangements with the remaining $6.8 million classified as current risk management assets. Available-for-sale securities are comprised of the following: Amortized Cost Gross Unrealized Gain Gross Unrealized Loss Fair Value (In thousands) As of June 30, 2017 Domestic equity mutual funds $ 25,236 $ 7,749 $ (17 ) $ 32,968 Foreign equity mutual funds 4,581 1,857 — 6,438 Bond mutual funds 15,928 — (36 ) 15,892 Bonds 31,407 52 (30 ) 31,429 Money market funds 2,884 — — 2,884 $ 80,036 $ 9,658 $ (83 ) $ 89,611 As of September 30, 2016 Domestic equity mutual funds $ 26,692 $ 6,419 $ (590 ) $ 32,521 Foreign equity mutual funds 4,954 1,202 — 6,156 Bonds 31,296 108 (10 ) 31,394 Money market funds 2,630 — — 2,630 $ 65,572 $ 7,729 $ (600 ) $ 72,701 At June 30, 2017 and September 30, 2016 , our available-for-sale securities included $42.3 million and $41.3 million related to assets held in separate rabbi trusts for our supplemental executive benefit plans. At June 30, 2017 , we maintained investments in bonds that have contractual maturity dates ranging from July 2017 through December 2020. These securities are reported at market value with unrealized gains and losses shown as a component of accumulated other comprehensive income (loss). We regularly evaluate the performance of these investments on a fund by fund basis for impairment, taking into consideration the fund’s purpose, volatility and current returns. If a determination is made that a decline in fair value is other than temporary, the related fund is written down to its estimated fair value and the other-than-temporary impairment is recognized in the income statement. Other Fair Value Measures Our debt is recorded at carrying value. The fair value of our debt is determined using third party market value quotations, which are considered Level 1 fair value measurements for debt instruments with a recent, observable trade or Level 2 fair value measurements for debt instruments where fair value is determined using the most recent available quoted market price. The following table presents the carrying value and fair value of our debt as of June 30, 2017 and September 30, 2016 : June 30, 2017 September 30, 2016 (In thousands) Carrying Amount $ 3,085,000 $ 2,460,000 Fair Value $ 3,388,003 $ 2,844,990

Concentration of Credit Risk

Concentration of Credit Risk	9 Months Ended
	Jun. 30, 2017
Risks and Uncertainties [Abstract]
Concentration of Credit Risk	Concentration of Credit Risk Information regarding our concentration of credit risk is disclosed in Note 16 of our Fiscal 2016 Financial Statements. Except for the sale of AEM, during the nine months ended June 30, 2017 , there were no material changes in our concentration of credit risk.

Accounting Policies (Policy)

Accounting Policies (Policy)	9 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
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 substantially all of our regulatory liabilities are recorded as a component of deferred credits and other liabilities. Deferred gas costs are recorded either in other current assets or liabilities and the regulatory cost of removal obligation is reported separately.
Segment Reporting	Segment Information Through November 30, 2016, our consolidated operations were managed and reviewed through three segments: • The regulated distribution segment , which included our regulated natural gas distribution and related sales operations. • The regulated pipeline segment , which included the pipeline and storage operations of our Atmos Pipeline-Texas division and, • The nonregulated segment , which included our nonregulated natural gas management, nonregulated natural gas transmission, storage and other services. As a result of the announced sale of Atmos Energy Marketing, we revised the information used by the chief operating decision maker to manage the Company, effective December 1, 2016. Accordingly, we have been managing and reviewing our consolidated operations through the following three reportable segments: • The distribution segment is primarily comprised of our regulated natural gas distribution and related sales operations in eight states and storage assets located in Kentucky and Tennessee, which are used solely to support our natural gas distribution operations in those states. These storage assets were formerly included in our nonregulated segment. • 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, which were formerly included in our nonregulated segment. • The natural gas marketing segment is comprised of our discontinued natural gas marketing business. Our determination of reportable segments considers the strategic operating units under which we manage sales of various products and services to customers in differing regulatory environments. Although our distribution segment operations are geographically dispersed, they are aggregated and reported as a single segment as each natural gas distribution division has similar economic characteristics. In addition, because the pipeline and storage operations of our Atmos Pipeline-Texas division and our natural gas transmission operations in Louisiana have similar economic characteristics, they have been aggregated and reported as a single segment. The accounting policies of the segments are the same as those described in the summary of significant accounting policies found in our Fiscal 2016 Financial Statements. We evaluate performance based on net income or loss of the respective operating segments. We allocate interest and pension expense to the pipeline and storage segment; however, there is no debt or pension liability recorded on the pipeline and storage segment balance sheet. All material intercompany transactions have been eliminated; however, we have not eliminated intercompany profits when such amounts are probable of recovery under the affiliates’ rate regulation process.
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 of our Fiscal 2016 Financial Statements. During the nine months ended June 30, 2017 , there were no changes in these methods.

Unaudited Financial Informati22

Unaudited Financial Information (Table)	9 Months Ended
	Jun. 30, 2017
Regulatory Assets And Liabilities Table [Abstract]
Schedule Of Regulatory Assets And Liabilities [Table Text Block]	Significant regulatory assets and liabilities as of June 30, 2017 and September 30, 2016 included the following: June 30, September 30, (In thousands) Regulatory assets: Pension and postretirement benefit costs (1) $ 122,202 $ 132,348 Infrastructure mechanisms (2) 38,653 42,719 Deferred gas costs 16,405 45,184 Recoverable loss on reacquired debt 11,843 13,761 Deferred pipeline record collection costs 10,327 7,336 APT annual adjustment mechanism 4,973 7,171 Rate case costs 2,480 1,539 Other 9,949 13,565 $ 216,832 $ 263,623 Regulatory liabilities: Regulatory cost of removal obligations $ 492,404 $ 476,891 Deferred gas costs 16,753 20,180 Asset retirement obligations 13,404 13,404 Other 6,729 4,250 $ 529,290 $ 514,725 (1) Includes $11.5 million and $12.4 million of pension and postretirement expense deferred pursuant to regulatory authorization. (2) 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.

Segment Information (Table)

Segment Information (Table)	9 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Income statements for the three and nine months ended June 30, 2017 and 2016 by segment are presented in the following tables: Three Months Ended June 30, 2017 Distribution Pipeline and Storage Natural Gas Marketing Eliminations Consolidated (In thousands) Operating revenues from external parties $ 493,738 $ 32,763 $ — $ — $ 526,501 Intersegment revenues 322 84,520 — (84,842 ) — Total operating revenues 494,060 117,283 — (84,842 ) 526,501 Purchased gas cost 197,767 1,251 — (84,842 ) 114,176 Operation and maintenance expense 99,631 29,059 — — 128,690 Depreciation and amortization expense 62,760 17,263 — — 80,023 Taxes, other than income 56,850 6,098 — — 62,948 Operating income 77,052 63,612 — — 140,664 Miscellaneous expense (62 ) (227 ) — — (289 ) Interest charges 18,394 10,104 — — 28,498 Income before income taxes 58,596 53,281 — — 111,877 Income tax expense 22,082 18,987 — — 41,069 Net income $ 36,514 $ 34,294 $ — $ — $ 70,808 Capital expenditures $ 205,780 $ 46,983 $ — $ — $ 252,763 Three Months Ended June 30, 2016 Distribution Pipeline and Storage Natural Gas Marketing Eliminations Consolidated (In thousands) Operating revenues from external parties $ 424,553 $ 31,659 $ — $ — $ 456,212 Intersegment revenues 352 82,196 — (82,548 ) — Total operating revenues 424,905 113,855 — (82,548 ) 456,212 Purchased gas cost 147,569 (438 ) — (82,548 ) 64,583 Operation and maintenance expense 101,819 29,569 — — 131,388 Depreciation and amortization expense 59,193 13,687 — — 72,880 Taxes, other than income 52,662 6,303 — — 58,965 Operating income 63,662 64,734 — — 128,396 Miscellaneous income (expense) 1,243 (125 ) — — 1,118 Interest charges 18,677 9,002 — — 27,679 Income from continuing operations before income taxes 46,228 55,607 — — 101,835 Income tax expense 15,867 19,825 — — 35,692 Income from continuing operations 30,361 35,782 — — 66,143 Income from discontinued operations, net of tax — — 5,050 — 5,050 Net income $ 30,361 $ 35,782 $ 5,050 $ — $ 71,193 Capital expenditures $ 187,470 $ 66,108 $ 106 $ — $ 253,684 Nine Months Ended June 30, 2017 Distribution Pipeline and Storage Natural Gas Marketing Eliminations Consolidated (In thousands) Operating revenues from external parties $ 2,210,221 $ 84,634 $ — $ — $ 2,294,855 Intersegment revenues 1,036 254,573 — (255,609 ) — Total operating revenues 2,211,257 339,207 — (255,609 ) 2,294,855 Purchased gas cost 1,106,209 2,331 — (255,565 ) 852,975 Operation and maintenance expense 296,048 89,863 — (44 ) 385,867 Depreciation and amortization expense 185,219 49,429 — — 234,648 Taxes, other than income 165,032 20,579 — — 185,611 Operating income 458,749 177,005 — — 635,754 Miscellaneous income (expense) 334 (784 ) — — (450 ) Interest charges 56,437 30,035 — — 86,472 Income from continuing operations before income taxes 402,646 146,186 — — 548,832 Income tax expense 149,623 52,351 — — 201,974 Income from continuing operations 253,023 93,835 — — 346,858 Income from discontinued operations, net of tax — — 10,994 — 10,994 Gain on sale of discontinued operations, net of tax — — 2,716 — 2,716 Net income $ 253,023 $ 93,835 $ 13,710 $ — $ 360,568 Capital expenditures $ 636,449 $ 175,699 $ — $ — $ 812,148 Nine Months Ended June 30, 2016 Distribution Pipeline and Storage Natural Gas Marketing Eliminations Consolidated (In thousands) Operating revenues from external parties $ 1,935,421 $ 85,584 $ — $ — $ 2,021,005 Intersegment revenues 1,054 228,840 — (229,894 ) — Total operating revenues 1,936,475 314,424 — (229,894 ) 2,021,005 Purchased gas cost 912,231 (72 ) — (229,894 ) 682,265 Operation and maintenance expense 294,154 84,919 — — 379,073 Depreciation and amortization expense 174,748 40,179 — — 214,927 Taxes, other than income 153,198 18,761 — — 171,959 Operating income 402,144 170,637 — — 572,781 Miscellaneous income (expense) 804 (894 ) — — (90 ) Interest charges 57,481 27,294 — — 84,775 Income from continuing operations before income taxes 345,467 142,449 — — 487,916 Income tax expense 126,090 51,134 — — 177,224 Income from continuing operations 219,377 91,315 — — 310,692 Income from discontinued operations, net of tax — — 5,172 — 5,172 Net income $ 219,377 $ 91,315 $ 5,172 $ — $ 315,864 Capital expenditures $ 528,063 $ 261,446 $ 179 $ — $ 789,688 Balance sheet information at June 30, 2017 and September 30, 2016 by segment is presented in the following tables: June 30, 2017 Distribution Pipeline and Storage Natural Gas Marketing Eliminations Consolidated (In thousands) ASSETS Property, plant and equipment, net $ 6,678,875 $ 2,245,506 $ — $ — $ 8,924,381 Investment in subsidiaries 798,994 13,851 — (812,845 ) — Current assets Cash and cash equivalents 69,777 — — — 69,777 Other current assets 437,700 29,265 — (2,360 ) 464,605 Intercompany receivables 983,866 — — (983,866 ) — Total current assets 1,491,343 29,265 — (986,226 ) 534,382 Goodwill 586,661 143,012 — — 729,673 Deferred charges and other assets 280,240 30,099 — — 310,339 $ 9,836,113 $ 2,461,733 $ — $ (1,799,071 ) $ 10,498,775 CAPITALIZATION AND LIABILITIES Shareholders’ equity $ 3,901,710 $ 812,845 $ — $ (812,845 ) $ 3,901,710 Long-term debt 3,066,734 — — — 3,066,734 Total capitalization 6,968,444 812,845 — (812,845 ) 6,968,444 Current liabilities Short-term debt 258,573 — — — 258,573 Other current liabilities 451,026 38,420 — (2,360 ) 487,086 Intercompany payables — 983,866 — (983,866 ) — Total current liabilities 709,599 1,022,286 — (986,226 ) 745,659 Deferred income taxes 1,251,528 602,036 — — 1,853,564 Regulatory cost of removal obligation 432,531 24,529 — — 457,060 Pension and postretirement liabilities 304,919 — — — 304,919 Deferred credits and other liabilities 169,092 37 — — 169,129 $ 9,836,113 $ 2,461,733 $ — $ (1,799,071 ) $ 10,498,775 September 30, 2016 Distribution Pipeline and Storage Natural Gas Marketing Eliminations Consolidated (In thousands) ASSETS Property, plant and equipment, net $ 6,208,465 $ 2,060,141 $ — $ — $ 8,268,606 Investment in subsidiaries 768,415 13,854 — (782,269 ) — Current assets Cash and cash equivalents 22,117 — 25,417 — 47,534 Current assets of disposal group classified as held for sale — — 162,508 (11,391 ) 151,117 Other current assets 489,963 39,078 5 (46,011 ) 483,035 Intercompany receivables 971,665 — — (971,665 ) — Total current assets 1,483,745 39,078 187,930 (1,029,067 ) 681,686 Goodwill 583,950 143,012 — — 726,962 Noncurrent assets of disposal group classified as held for sale — — 28,785 (169 ) 28,616 Deferred charges and other assets 277,240 27,779 — — 305,019 $ 9,321,815 $ 2,283,864 $ 216,715 $ (1,811,505 ) $ 10,010,889 CAPITALIZATION AND LIABILITIES Shareholders’ equity $ 3,463,059 $ 715,672 $ 66,597 $ (782,269 ) $ 3,463,059 Long-term debt 2,188,779 — — — 2,188,779 Total capitalization 5,651,838 715,672 66,597 (782,269 ) 5,651,838 Current liabilities Current maturities of long-term debt 250,000 — — — 250,000 Short-term debt 829,811 — 35,000 (35,000 ) 829,811 Current liabilities of the disposal group classified as held for sale — — 81,908 (9,008 ) 72,900 Other current liabilities 605,790 39,911 3,263 (13,394 ) 635,570 Intercompany payables — 957,526 14,139 (971,665 ) — Total current liabilities 1,685,601 997,437 134,310 (1,029,067 ) 1,788,281 Deferred income taxes 1,055,348 543,390 4,318 — 1,603,056 Regulatory cost of removal obligation 397,162 27,119 — — 424,281 Pension and postretirement liabilities 297,743 — — — 297,743 Noncurrent liabilities of disposal group classified as held for sale — — 316 — 316 Deferred credits and other liabilities 234,123 246 11,174 (169 ) 245,374 $ 9,321,815 $ 2,283,864 $ 216,715 $ (1,811,505 ) $ 10,010,889

Earnings Per Share (Table)

Earnings Per Share (Table)	9 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Earnings per share table	Basic and diluted earnings per share for the three and nine months ended June 30, 2017 and 2016 are calculated as follows: Three Months Ended Nine Months Ended 2017 2016 2017 2016 (In thousands, except per share amounts) Basic and Diluted Earnings Per Share from continuing operations Income from continuing operations $ 70,808 $ 66,143 $ 346,858 $ 310,692 Less: Income from continuing operations allocated to participating securities 75 100 424 488 Income from continuing operations available to common shareholders $ 70,733 $ 66,043 $ 346,434 $ 310,204 Basic and diluted weighted average shares outstanding 106,364 103,750 105,862 103,137 Income from continuing operations per share — Basic and Diluted $ 0.67 $ 0.64 $ 3.27 $ 3.01 Basic and Diluted Earnings Per Share from discontinued operations Income from discontinued operations $ — $ 5,050 $ 13,710 $ 5,172 Less: Income from discontinued operations allocated to participating securities — 6 15 4 Income from discontinued operations available to common shareholders $ — $ 5,044 $ 13,695 $ 5,168 Basic and diluted weighted average shares outstanding 106,364 103,750 105,862 103,137 Income from discontinued operations per share — Basic and Diluted $ — $ 0.05 $ 0.13 $ 0.05 Net income per share — Basic and Diluted $ 0.67 $ 0.69 $ 3.40 $ 3.06

Debt (Table)

Debt (Table)	9 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Components of Debt	Long-term debt at June 30, 2017 and September 30, 2016 consisted of the following: June 30, 2017 September 30, 2016 (In thousands) Unsecured 6.35% Senior Notes, due June 2017 $ — $ 250,000 Unsecured 8.50% Senior Notes, due 2019 450,000 450,000 Unsecured 3.00% Senior Notes, due 2027 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 750,000 500,000 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 2019 125,000 — Total long-term debt 3,085,000 2,460,000 Less: Original issue (premium) discount on unsecured senior notes and debentures (4,370 ) 4,270 Debt issuance cost 22,636 16,951 Current maturities — 250,000 $ 3,066,734 $ 2,188,779

Divestitures and Acquisitions (

Divestitures and Acquisitions (Tables)	9 Months Ended
	Jun. 30, 2017
Divestitures and Acquisitions [Abstract]
Disposal Groups, Including Discontinued Operations [Table Text Block]	The following tables present statement of income data related to discontinued operations: Three Months Ended 2017 2016 (In thousands) Operating revenues $ — $ 200,213 Purchased gas cost — 184,398 Operating expenses — 7,047 Operating income — 8,768 Other nonoperating expense — (304 ) Income from discontinued operations before income taxes — 8,464 Income tax expense — 3,414 Net income from discontinued operations $ — $ 5,050 Nine Months Ended 2017 2016 (In thousands) Operating revenues $ 303,474 $ 728,989 Purchased gas cost 277,554 698,445 Operating expenses 7,874 19,940 Operating income 18,046 10,604 Other nonoperating expense (211 ) (1,937 ) Income from discontinued operations before income taxes 17,835 8,667 Income tax expense 6,841 3,495 Income from discontinued operations 10,994 5,172 Gain on sale from discontinued operations, net of tax ($10,215 and $0) 2,716 — Net income from discontinued operations $ 13,710 $ 5,172 The following table presents a reconciliation of the carrying amounts of major classes of assets and liabilities of our natural gas marketing's operations to total assets and liabilities classified as held for sale: June 30, 2017 September 30, 2016 (In thousands) Assets: Net property, plant and equipment $ — $ 11,905 Accounts receivable — 93,551 Gas stored underground — 54,246 Other current assets — 14,711 Goodwill — 16,445 Deferred charges and other assets — 435 Total assets of the disposal group classified as held for sale in the statement of financial position (1) — 191,293 Cash — 25,417 Other assets — 5 Total assets of disposal group in the statement of financial position $ — $ 216,715 Liabilities: Accounts payable and accrued liabilities $ — $ 72,268 Other current liabilities — 9,640 Deferred credits and other — 316 Total liabilities of the disposal group classified as held for sale in the statement of financial position (1) — 82,224 Intercompany note payable — 35,000 Tax liabilities — 15,471 Intercompany payables — 14,139 Other liabilities — 3,284 Total liabilities of disposal group in the statement of financial position $ — $ 150,118 (1) Amounts in the comparative period are classified as current and long term in the statement of financial position. The following table presents statement of cash flow data related to discontinued operations: Nine Months Ended 2017 2016 (In thousands) Depreciation and amortization expense $ 185 $ 1,743 Capital expenditures $ — $ 179 Noncash gain (loss) in commodity contract cash flow hedges $ 18,744 $ (33,898 )

Shareholders' Equity (Table)

Shareholders' Equity (Table)	9 Months Ended
	Jun. 30, 2017
Equity [Abstract]
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 Interest Rate Agreement Cash Flow Hedges Commodity Contracts Cash Flow Hedges Total (In thousands) September 30, 2016 $ 4,484 $ (187,524 ) $ (4,982 ) $ (188,022 ) Other comprehensive income before reclassifications 1,485 76,602 9,847 87,934 Amounts reclassified from accumulated other comprehensive income 68 286 (4,865 ) (4,511 ) Net current-period other comprehensive income 1,553 76,888 4,982 83,423 June 30, 2017 $ 6,037 $ (110,636 ) $ — $ (104,599 ) Available- for-Sale Securities Interest Rate Agreement Cash Flow Hedges Commodity Contracts Cash Flow Hedges Total (In thousands) September 30, 2015 $ 4,949 $ (88,842 ) $ (25,437 ) $ (109,330 ) Other comprehensive loss before reclassifications (1,417 ) (88,345 ) (8,612 ) (98,374 ) Amounts reclassified from accumulated other comprehensive income (79 ) 260 29,290 29,471 Net current-period other comprehensive income (loss) (1,496 ) (88,085 ) 20,678 (68,903 ) June 30, 2016 $ 3,453 $ (176,927 ) $ (4,759 ) $ (178,233 )
Reclassification out of Accumulated Other Comprehensive Income	The following tables detail reclassifications out of AOCI for the three and nine months ended June 30, 2017 and 2016 . Amounts in parentheses below indicate decreases to net income in the statement of income: Three Months Ended June 30, 2017 Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement of Income (In thousands) Cash flow hedges Interest rate agreements $ (177 ) Interest charges Commodity contracts — Purchased gas cost (177 ) Total before tax 64 Tax benefit Total reclassifications $ (113 ) Net of tax Three Months Ended June 30, 2016 Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement of Income (In thousands) Cash flow hedges Interest rate agreements $ (137 ) Interest charges Commodity contracts (12,347 ) Purchased gas cost (1) (12,484 ) Total before tax 4,865 Tax benefit Total reclassifications $ (7,619 ) Net of tax Nine Months Ended June 30, 2017 Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement of Income (In thousands) Available-for-sale securities $ (107 ) Operation and maintenance expense (107 ) Total before tax 39 Tax benefit $ (68 ) Net of tax Cash flow hedges Interest rate agreements $ (450 ) Interest charges Commodity contracts 7,976 Purchased gas cost (1) 7,526 Total before tax (2,947 ) Tax expense $ 4,579 Net of tax Total reclassifications $ 4,511 Net of tax Nine Months Ended June 30, 2016 Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement of Income (In thousands) Available-for-sale securities $ 124 Operation and maintenance expense 124 Total before tax (45 ) Tax expense $ 79 Net of tax Cash flow hedges Interest rate agreements $ (410 ) Interest charges Commodity contracts (48,015 ) Purchased gas cost (1) (48,425 ) Total before tax 18,875 Tax benefit $ (29,550 ) Net of tax Total reclassifications $ (29,471 ) Net of tax (1) Amounts are presented as part of income from discontinued operations on the condensed consolidated statements of income.

Interim Pension and Other Pos28

Interim Pension and Other Postretirement Benefits (Table)	9 Months Ended
	Jun. 30, 2017
General Discussion of Pension and Other Postretirement Benefits [Abstract]
Components of net periodic pension cost table	The components of our net periodic pension cost for our pension and other postretirement benefit plans for the three and nine months ended June 30, 2017 and 2016 are presented in the following table. Most of these costs are recoverable through our tariff rates; however, a portion of these costs is capitalized into our rate base. The remaining costs are recorded as a component of operation and maintenance expense. Three Months Ended June 30 Pension Benefits Other Benefits 2017 2016 2017 2016 (In thousands) Components of net periodic pension cost: Service cost $ 5,216 $ 4,698 $ 3,109 $ 2,705 Interest cost 6,296 7,095 2,669 3,106 Expected return on assets (6,993 ) (6,881 ) (1,796 ) (1,566 ) Amortization of transition obligation — — — 21 Amortization of prior service credit (57 ) (57 ) (411 ) (411 ) Amortization of actuarial (gain) loss 4,248 3,319 (706 ) (541 ) Net periodic pension cost $ 8,710 $ 8,174 $ 2,865 $ 3,314 Nine Months Ended June 30 Pension Benefits Other Benefits 2017 2016 2017 2016 (In thousands) Components of net periodic pension cost: Service cost $ 15,649 $ 14,093 $ 9,327 $ 8,117 Interest cost 18,890 21,284 8,009 9,318 Expected return on assets (20,981 ) (20,642 ) (5,389 ) (4,698 ) Amortization of transition obligation — — — 62 Amortization of prior service credit (173 ) (170 ) (1,233 ) (1,233 ) Amortization of actuarial (gain) loss 12,746 9,959 (2,120 ) (1,625 ) Net periodic pension cost $ 26,131 $ 24,524 $ 8,594 $ 9,941
Schedule of assumptions used table text block	The assumptions used to develop our net periodic pension cost for the three and nine months ended June 30, 2017 and 2016 are as follows: Pension Benefits Other Benefits 2017 2016 2017 2016 Discount rate 3.73% 4.55% 3.73% 4.55% Rate of compensation increase 3.50% 3.50% N/A N/A Expected return on plan assets 7.00% 7.00% 4.45% 4.45%

Financial Instruments (Table)

Financial Instruments (Table)	9 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial instruments on the balance sheet	Balance Sheet Location Assets Liabilities (In thousands) September 30, 2016 Designated As Hedges: Commodity contracts Other current assets / Other current liabilities $ 6,612 $ (21,903 ) Interest rate contracts Other current assets / — (68,481 ) Commodity contracts Deferred charges and other assets / Deferred credits and other liabilities 2,178 (3,779 ) Interest rate contracts Deferred charges and other assets / Deferred credits and other liabilities — (198,008 ) Total 8,790 (292,171 ) Not Designated As Hedges: Commodity contracts Other current assets / Other current liabilities 21,186 (18,812 ) Commodity contracts Deferred charges and other assets / Deferred credits and other liabilities 14,165 (12,701 ) Total 35,351 (31,513 ) Gross Financial Instruments 44,141 (323,684 ) Gross Amounts Offset on Consolidated Balance Sheet: Contract netting (39,290 ) 39,290 Net Financial Instruments 4,851 (284,394 ) Cash collateral 6,775 43,575 Net Assets/Liabilities from Risk Management Activities $ 11,626 $ (240,819 ) The following tables present the fair value and balance sheet classification of our financial instruments as of June 30, 2017 and September 30, 2016 . 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 the counterparties. Balance Sheet Location Assets Liabilities (In thousands) June 30, 2017 Designated As Hedges: Interest rate contracts Deferred credits and other liabilities — (108,860 ) Total — (108,860 ) Not Designated As Hedges: Commodity contracts Other current assets / Other current liabilities 2,960 (230 ) Commodity contracts Deferred charges and other assets / Deferred credits and other liabilities 268 (282 ) Total 3,228 (512 ) Gross Financial Instruments 3,228 (109,372 ) Gross Amounts Offset on Consolidated Balance Sheet: Contract netting — — Net Financial Instruments 3,228 (109,372 ) Cash collateral — — Net Assets/Liabilities from Risk Management Activities $ 3,228 $ (109,372 )
Fair value hedges table	The impact of our natural gas marketing segment commodity contracts designated as fair value hedges and the related hedged item on the results of discontinued operations on our condensed consolidated income statement for the three and nine months ended June 30, 2017 and 2016 is presented below. Three Months Ended Nine Months Ended 2017 2016 2017 2016 (In thousands) Commodity contracts $ — $ (22,146 ) $ (9,567 ) $ (11,808 ) Fair value adjustment for natural gas inventory designated as the hedged item — 35,630 12,858 29,852 Total decrease in purchased gas cost reflected in income from discontinued operations $ — $ 13,484 $ 3,291 $ 18,044 The decrease in purchased gas cost reflected in income from discontinued operations is comprised of the following: Basis ineffectiveness $ — $ (684 ) $ (597 ) $ (1,490 ) Timing ineffectiveness — 14,168 3,888 19,534 $ — $ 13,484 $ 3,291 $ 18,044
Cash flow hedges	The impact of our interest rate and natural gas marketing segment cash flow hedges on our condensed consolidated income statements for the three and nine months ended June 30, 2017 and 2016 is presented below. Three Months Ended Nine Months Ended 2017 2016 2017 2016 (In thousands) Loss reclassified from AOCI for effective portion of natural gas marketing commodity contracts $ — $ (12,347 ) $ (2,612 ) $ (48,015 ) Gain arising from ineffective portion of natural gas marketing commodity contracts — 66 111 84 Gain on discontinuance of cash flow hedging of natural gas marketing commodity contracts reclassified from AOCI — — 10,579 — Total impact on purchased gas cost reflected in income from discontinued operations — (12,281 ) 8,078 (47,931 ) Net loss on settled interest rate agreements reclassified from AOCI into interest expense (177 ) (137 ) (450 ) (410 ) Total Impact from Cash Flow Hedges $ (177 ) $ (12,418 ) $ 7,628 $ (48,341 )
Other comprehensive income from hedging table	The following table summarizes the gains and losses arising from hedging transactions that were recognized as a component of other comprehensive income (loss), net of taxes, for the three and nine months ended June 30, 2017 and 2016 . The amounts included in the table below exclude gains and losses arising from ineffectiveness because those amounts are immediately recognized in the income statement as incurred. Three Months Ended Nine Months Ended 2017 2016 2017 2016 (In thousands) Increase (decrease) in fair value: Interest rate agreements $ (18,669 ) $ (39,337 ) $ 76,602 $ (88,345 ) Forward commodity contracts — 10,573 9,847 (8,612 ) Recognition of (gains) losses in earnings due to settlements: Interest rate agreements 113 87 286 260 Forward commodity contracts — 7,532 (4,865 ) 29,290 Total other comprehensive income (loss) from hedging, net of tax (1) $ (18,556 ) $ (21,145 ) $ 81,870 $ (67,407 ) (1) Utilizing an income tax rate ranging from 37 percent to 39 percent based on the effective rates in each taxing jurisdiction.
Expected recognition in earnings of deferred gains/(losses) in AOCI table	The following amounts, net of deferred taxes, represent the expected recognition in earnings of the deferred losses recorded in AOCI associated with our financial instruments, based upon the fair values of these financial instruments as of June 30, 2017 . 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 $ (1,509 ) Thereafter (40,001 ) Total (1) $ (41,510 ) (1) Utilizing an income tax rate of 37 percent

Fair Value Measurements (Table)

Fair Value Measurements (Table)	9 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Fair value measurements table	The following tables summarize, by level within the fair value hierarchy, our assets and liabilities that were accounted for at fair value on a recurring basis as of June 30, 2017 and September 30, 2016 . Assets and liabilities are categorized in their entirety based on the lowest level of input that is significant to the fair value measurement. Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) (1) Significant Other Unobservable Inputs (Level 3) Netting and Cash Collateral June 30, 2017 (In thousands) Assets: Financial instruments $ — $ 3,228 $ — $ — $ 3,228 Available-for-sale securities Registered investment companies 39,406 — — — 39,406 Bond mutual funds 15,892 — — — 15,892 Bonds — 31,429 — — 31,429 Money market funds — 2,884 — — 2,884 Total available-for-sale securities 55,298 34,313 — — 89,611 Total assets $ 55,298 $ 37,541 $ — $ — $ 92,839 Liabilities: Financial instruments $ — $ 109,372 $ — $ — $ 109,372 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) (1) Significant Other Unobservable Inputs (Level 3) Netting and Cash Collateral (2) September 30, 2016 (In thousands) Assets: Financial instruments $ — $ 44,141 $ — $ (32,515 ) $ 11,626 Hedged portion of gas stored underground 52,578 — — — 52,578 Available-for-sale securities Registered investment companies 38,677 — — — 38,677 Bonds — 31,394 — — 31,394 Money market funds — 2,630 — — 2,630 Total available-for-sale securities 38,677 34,024 — — 72,701 Total assets $ 91,255 $ 78,165 $ — $ (32,515 ) $ 136,905 Liabilities: Financial instruments $ — $ 323,684 $ — $ (82,865 ) $ 240,819 (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 which are valued at cost. (2) This column reflects adjustments to our gross financial instrument assets and liabilities to reflect netting permitted under our master netting agreements and the relevant authoritative accounting literature. As of September 30, 2016 , we had $50.4 million of cash held in margin accounts to collateralize certain financial instruments. Of this amount, $43.6 million was used to offset current and noncurrent risk management liabilities under master netting arrangements with the remaining $6.8 million classified as current risk management assets.
Schedule of Available-for-sale Securities Reconciliation Table	Available-for-sale securities are comprised of the following: Amortized Cost Gross Unrealized Gain Gross Unrealized Loss Fair Value (In thousands) As of June 30, 2017 Domestic equity mutual funds $ 25,236 $ 7,749 $ (17 ) $ 32,968 Foreign equity mutual funds 4,581 1,857 — 6,438 Bond mutual funds 15,928 — (36 ) 15,892 Bonds 31,407 52 (30 ) 31,429 Money market funds 2,884 — — 2,884 $ 80,036 $ 9,658 $ (83 ) $ 89,611 As of September 30, 2016 Domestic equity mutual funds $ 26,692 $ 6,419 $ (590 ) $ 32,521 Foreign equity mutual funds 4,954 1,202 — 6,156 Bonds 31,296 108 (10 ) 31,394 Money market funds 2,630 — — 2,630 $ 65,572 $ 7,729 $ (600 ) $ 72,701
Other fair value measurements table	The following table presents the carrying value and fair value of our debt as of June 30, 2017 and September 30, 2016 : June 30, 2017 September 30, 2016 (In thousands) Carrying Amount $ 3,085,000 $ 2,460,000 Fair Value $ 3,388,003 $ 2,844,990

Nature of Business (Details)

Nature of Business (Details) customers in Millions	Jun. 30, 2017statecustomersregulated_gas_distributions_divisions
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of Customers, Regulated Distribution | customers	3
Number of Divisions, Regulated Distribution | regulated_gas_distributions_divisions	6
Number of States in which Entity Operates | state	8

Unaudited Interim Financial Inf

Unaudited Interim Financial Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2017	Aug. 01, 2017	Jan. 06, 2017	Sep. 30, 2016
Regulatory Asset [Line Items]
Regulatory assets	$ 216,832			$ 263,623
Regulatory asset - future recoverable pension costs	11,500			12,400
Regulatory Liabilities [Line Items]
Regulatory liabilities	529,290			514,725
Atmos Pipeline - Texas 2017 Rate Case [Member]
Subsequent Event [Line Items]
Annual Operating Income Increase, Statement of Intent			$ 63,600
State of Texas Use Tax [Member]
Use Tax Examination [Line Items]
Use Tax Refund	29,800
Use Tax Refund, Amount Received	18,700
Use Tax Refund Receivable	11,100
Subsequent Event [Member] | Atmos Pipeline - Texas 2017 Rate Case [Member]
Subsequent Event [Line Items]
Annual Operating Income Increase, Final Order		$ 13,000
Regulatory Cost of Removal [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	492,404			476,891
Deferred Gas Costs [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	16,753			20,180
Asset Retirement Obligation Costs [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	13,404			13,404
Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	6,729			4,250
Pension And Postretirement Benefit Costs [Member]
Regulatory Asset [Line Items]
Regulatory assets	122,202			132,348
Infrastructure Mechanisms [Member]
Regulatory Asset [Line Items]
Regulatory assets	38,653			42,719
Deferred Gas Costs [Member]
Regulatory Asset [Line Items]
Regulatory assets	16,405			45,184
Recoverable Loss On Reacquired Debt [Member]
Regulatory Asset [Line Items]
Regulatory assets	11,843			13,761
Deferred Project Costs [Member]
Regulatory Asset [Line Items]
Regulatory assets	10,327			7,336
APT Annual Adjustment Mechanism [Member]
Regulatory Asset [Line Items]
Regulatory assets	4,973			7,171
Rate Case Costs [Member]
Regulatory Asset [Line Items]
Regulatory assets	2,480			1,539
Other [Member]
Regulatory Asset [Line Items]
Regulatory assets	$ 9,949			$ 13,565

Segment Information (Details)

Segment Information (Details)	3 Months Ended		9 Months Ended
	Jun. 30, 2017USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)segment	Jun. 30, 2016USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segment			3
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	$ 526,501,000	$ 456,212,000	$ 2,294,855,000	$ 2,021,005,000
Purchased gas cost	114,176,000	64,583,000	852,975,000	682,265,000
Operation and maintenance expense	128,690,000	131,388,000	385,867,000	379,073,000
Depreciation and amortization expense	80,023,000	72,880,000	234,648,000	214,927,000
Taxes, other than income, expense	62,948,000	58,965,000	185,611,000	171,959,000
Operating income	140,664,000	128,396,000	635,754,000	572,781,000
Miscellaneous income (expense)	(289,000)	1,118,000	(450,000)	(90,000)
Interest charges	28,498,000	27,679,000	86,472,000	84,775,000
Income (loss) from continuing operations before income taxes	111,877,000	101,835,000	548,832,000	487,916,000
Income tax expense (benefit)	41,069,000	35,692,000	201,974,000	177,224,000
Income from continuing operations	70,808,000	66,143,000	346,858,000	310,692,000
Income from discontinued operations, net of tax	0	5,050,000	13,710,000	5,172,000
Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			2,716,000	0
Net income (loss)	70,808,000	71,193,000	360,568,000	315,864,000
Capital expenditures	252,763,000	253,684,000	812,148,000	789,688,000
Income from discontinued operations, net of tax, before gain on disposal	0	5,050,000	10,994,000	5,172,000
ASSETS
Net property, plant and equipment	8,924,381,000		8,924,381,000		$ 8,268,606,000
Investment in subsidiaries	0		0		0
Current assets
Cash and cash equivalents	69,777,000	66,206,000	69,777,000	66,206,000	47,534,000	$ 28,653,000
Current assets held for sale	0		0		151,117,000
Other current assets	464,605,000		464,605,000		483,035,000
Intercompany receivables	0		0		0
Total current assets	534,382,000		534,382,000		681,686,000
Goodwill	729,673,000		729,673,000		726,962,000
Noncurrent assets held for sale	0		0		28,616,000
Deferred charges and other assets	310,339,000		310,339,000		305,019,000
Total assets	10,498,775,000		10,498,775,000		10,010,889,000
CAPITALIZATION AND LIABILITIES
Shareholders' equity	3,901,710,000		3,901,710,000		3,463,059,000
Long-term debt	3,066,734,000		3,066,734,000		2,188,779,000
Total capitalization	6,968,444,000		6,968,444,000		5,651,838,000
Current liabilities
Current maturities of long-term debt	0		0		250,000,000
Short-term debt	258,573,000		258,573,000		829,811,000
Current liabilities held for sale	0		0		72,900,000
Other current liabilities	487,086,000		487,086,000		635,570,000
Intercompany payables	0		0		0
Total current liabilities	745,659,000		745,659,000		1,788,281,000
Deferred income taxes	1,853,564,000		1,853,564,000		1,603,056,000
Regulatory cost of removal obligation	457,060,000		457,060,000		424,281,000
Pension and postretirement liabilities	304,919,000		304,919,000		297,743,000
Noncurrent liabilities held for sale	0		0		316,000
Deferred credits and other liabilities	169,129,000		169,129,000		245,374,000
Total shareholders' equity and liabilities	10,498,775,000		10,498,775,000		10,010,889,000
Reportable Subsegments [Member]
Segment Reporting Information Profit Loss [Abstract]
Revenues	526,501,000	456,212,000	2,294,855,000	2,021,005,000
Intersubsegment Eliminations [Member]
Segment Reporting Information Profit Loss [Abstract]
Revenues	0	0	0	0
Distribution Segment [Member]
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	494,060,000	424,905,000	2,211,257,000	1,936,475,000
Purchased gas cost	197,767,000	147,569,000	1,106,209,000	912,231,000
Operation and maintenance expense	99,631,000	101,819,000	296,048,000	294,154,000
Depreciation and amortization expense	62,760,000	59,193,000	185,219,000	174,748,000
Taxes, other than income, expense	56,850,000	52,662,000	165,032,000	153,198,000
Operating income	77,052,000	63,662,000	458,749,000	402,144,000
Miscellaneous income (expense)	(62,000)	1,243,000	334,000	804,000
Interest charges	18,394,000	18,677,000	56,437,000	57,481,000
Income (loss) from continuing operations before income taxes	58,596,000	46,228,000	402,646,000	345,467,000
Income tax expense (benefit)	22,082,000	15,867,000	149,623,000	126,090,000
Income from continuing operations		30,361,000	253,023,000	219,377,000
Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			0
Net income (loss)	36,514,000	30,361,000	253,023,000	219,377,000
Capital expenditures	205,780,000	187,470,000	636,449,000	528,063,000
Income from discontinued operations, net of tax, before gain on disposal		0	0	0
ASSETS
Net property, plant and equipment	6,678,875,000		6,678,875,000		6,208,465,000
Investment in subsidiaries	798,994,000		798,994,000		768,415,000
Current assets
Cash and cash equivalents	69,777,000		69,777,000		22,117,000
Current assets held for sale					0
Other current assets	437,700,000		437,700,000		489,963,000
Intercompany receivables	983,866,000		983,866,000		971,665,000
Total current assets	1,491,343,000		1,491,343,000		1,483,745,000
Goodwill	586,661,000		586,661,000		583,950,000
Noncurrent assets held for sale					0
Deferred charges and other assets	280,240,000		280,240,000		277,240,000
Total assets	9,836,113,000		9,836,113,000		9,321,815,000
CAPITALIZATION AND LIABILITIES
Shareholders' equity	3,901,710,000		3,901,710,000		3,463,059,000
Long-term debt	3,066,734,000		3,066,734,000		2,188,779,000
Total capitalization	6,968,444,000		6,968,444,000		5,651,838,000
Current liabilities
Current maturities of long-term debt					250,000,000
Short-term debt	258,573,000		258,573,000		829,811,000
Current liabilities held for sale					0
Other current liabilities	451,026,000		451,026,000		605,790,000
Intercompany payables	0		0		0
Total current liabilities	709,599,000		709,599,000		1,685,601,000
Deferred income taxes	1,251,528,000		1,251,528,000		1,055,348,000
Regulatory cost of removal obligation	432,531,000		432,531,000		397,162,000
Pension and postretirement liabilities	304,919,000		304,919,000		297,743,000
Noncurrent liabilities held for sale					0
Deferred credits and other liabilities	169,092,000		169,092,000		234,123,000
Total shareholders' equity and liabilities	9,836,113,000		9,836,113,000		9,321,815,000
Distribution Segment [Member] | Reportable Subsegments [Member]
Segment Reporting Information Profit Loss [Abstract]
Revenues	493,738,000	424,553,000	2,210,221,000	1,935,421,000
Distribution Segment [Member] | Intersubsegment Eliminations [Member]
Segment Reporting Information Profit Loss [Abstract]
Revenues	322,000	352,000	1,036,000	1,054,000
Pipeline and Storage Segment [Member]
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	117,283,000	113,855,000	339,207,000	314,424,000
Purchased gas cost	1,251,000	(438,000)	2,331,000	(72,000)
Operation and maintenance expense	29,059,000	29,569,000	89,863,000	84,919,000
Depreciation and amortization expense	17,263,000	13,687,000	49,429,000	40,179,000
Taxes, other than income, expense	6,098,000	6,303,000	20,579,000	18,761,000
Operating income	63,612,000	64,734,000	177,005,000	170,637,000
Miscellaneous income (expense)	(227,000)	(125,000)	(784,000)	(894,000)
Interest charges	10,104,000	9,002,000	30,035,000	27,294,000
Income (loss) from continuing operations before income taxes	53,281,000	55,607,000	146,186,000	142,449,000
Income tax expense (benefit)	18,987,000	19,825,000	52,351,000	51,134,000
Income from continuing operations		35,782,000	93,835,000	91,315,000
Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			0
Net income (loss)	34,294,000	35,782,000	93,835,000	91,315,000
Capital expenditures	46,983,000	66,108,000	175,699,000	261,446,000
Income from discontinued operations, net of tax, before gain on disposal		0	0	0
ASSETS
Net property, plant and equipment	2,245,506,000		2,245,506,000		2,060,141,000
Investment in subsidiaries	13,851,000		13,851,000		13,854,000
Current assets
Cash and cash equivalents	0		0		0
Current assets held for sale					0
Other current assets	29,265,000		29,265,000		39,078,000
Intercompany receivables	0		0		0
Total current assets	29,265,000		29,265,000		39,078,000
Goodwill	143,012,000		143,012,000		143,012,000
Noncurrent assets held for sale					0
Deferred charges and other assets	30,099,000		30,099,000		27,779,000
Total assets	2,461,733,000		2,461,733,000		2,283,864,000
CAPITALIZATION AND LIABILITIES
Shareholders' equity	812,845,000		812,845,000		715,672,000
Long-term debt	0		0		0
Total capitalization	812,845,000		812,845,000		715,672,000
Current liabilities
Current maturities of long-term debt					0
Short-term debt	0		0		0
Current liabilities held for sale					0
Other current liabilities	38,420,000		38,420,000		39,911,000
Intercompany payables	983,866,000		983,866,000		957,526,000
Total current liabilities	1,022,286,000		1,022,286,000		997,437,000
Deferred income taxes	602,036,000		602,036,000		543,390,000
Regulatory cost of removal obligation	24,529,000		24,529,000		27,119,000
Pension and postretirement liabilities	0		0		0
Noncurrent liabilities held for sale					0
Deferred credits and other liabilities	37,000		37,000		246,000
Total shareholders' equity and liabilities	2,461,733,000		2,461,733,000		2,283,864,000
Pipeline and Storage Segment [Member] | Reportable Subsegments [Member]
Segment Reporting Information Profit Loss [Abstract]
Revenues	32,763,000	31,659,000	84,634,000	85,584,000
Pipeline and Storage Segment [Member] | Intersubsegment Eliminations [Member]
Segment Reporting Information Profit Loss [Abstract]
Revenues	84,520,000	82,196,000	254,573,000	228,840,000
Natural Gas Marketing Segment [Member]
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	0	0	0	0
Purchased gas cost	0	0	0	0
Operation and maintenance expense	0	0	0	0
Depreciation and amortization expense	0	0	0	0
Taxes, other than income, expense	0	0	0	0
Operating income	0	0	0	0
Miscellaneous income (expense)	0	0	0	0
Interest charges	0	0	0	0
Income (loss) from continuing operations before income taxes	0	0	0	0
Income tax expense (benefit)	0	0	0	0
Income from continuing operations		0	0	0
Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			2,716,000
Net income (loss)	0	5,050,000	13,710,000	5,172,000
Capital expenditures	0	106,000	0	179,000
Income from discontinued operations, net of tax, before gain on disposal		5,050,000	10,994,000	5,172,000
ASSETS
Net property, plant and equipment	0		0		0
Investment in subsidiaries	0		0		0
Current assets
Cash and cash equivalents	0		0		25,417,000
Current assets held for sale					162,508,000
Other current assets	0		0		5,000
Intercompany receivables	0		0		0
Total current assets	0		0		187,930,000
Goodwill	0		0		0
Noncurrent assets held for sale					28,785,000
Deferred charges and other assets	0		0		0
Total assets	0		0		216,715,000
CAPITALIZATION AND LIABILITIES
Shareholders' equity	0		0		66,597,000
Long-term debt	0		0		0
Total capitalization	0		0		66,597,000
Current liabilities
Current maturities of long-term debt					0
Short-term debt	0		0		35,000,000
Current liabilities held for sale					81,908,000
Other current liabilities	0		0		3,263,000
Intercompany payables	0		0		14,139,000
Total current liabilities	0		0		134,310,000
Deferred income taxes	0		0		4,318,000
Regulatory cost of removal obligation	0		0		0
Pension and postretirement liabilities	0		0		0
Noncurrent liabilities held for sale					316,000
Deferred credits and other liabilities	0		0		11,174,000
Total shareholders' equity and liabilities	0		0		216,715,000
Natural Gas Marketing Segment [Member] | Reportable Subsegments [Member]
Segment Reporting Information Profit Loss [Abstract]
Revenues	0	0	0	0
Natural Gas Marketing Segment [Member] | Intersubsegment Eliminations [Member]
Segment Reporting Information Profit Loss [Abstract]
Revenues	0	0	0	0
Intersegment Elimination [Member]
Segment Reporting Information Profit Loss [Abstract]
Total operating revenues	(84,842,000)	(82,548,000)	(255,609,000)	(229,894,000)
Purchased gas cost	(84,842,000)	(82,548,000)	(255,565,000)	(229,894,000)
Operation and maintenance expense	0	0	(44,000)	0
Depreciation and amortization expense	0	0	0	0
Taxes, other than income, expense	0	0	0	0
Operating income	0	0	0	0
Miscellaneous income (expense)	0	0	0	0
Interest charges	0	0	0	0
Income (loss) from continuing operations before income taxes	0	0	0	0
Income tax expense (benefit)	0	0	0	0
Income from continuing operations		0	0	0
Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			0
Net income (loss)	0	0	0	0
Capital expenditures	0	0	0	0
Income from discontinued operations, net of tax, before gain on disposal		0	0	0
ASSETS
Net property, plant and equipment	0		0		0
Investment in subsidiaries	(812,845,000)		(812,845,000)		(782,269,000)
Current assets
Cash and cash equivalents	0		0		0
Current assets held for sale					(11,391,000)
Other current assets	(2,360,000)		(2,360,000)		(46,011,000)
Intercompany receivables	(983,866,000)		(983,866,000)		(971,665,000)
Total current assets	(986,226,000)		(986,226,000)		(1,029,067,000)
Goodwill	0		0		0
Noncurrent assets held for sale					(169,000)
Deferred charges and other assets	0		0		0
Total assets	(1,799,071,000)		(1,799,071,000)		(1,811,505,000)
CAPITALIZATION AND LIABILITIES
Shareholders' equity	(812,845,000)		(812,845,000)		(782,269,000)
Long-term debt	0		0		0
Total capitalization	(812,845,000)		(812,845,000)		(782,269,000)
Current liabilities
Current maturities of long-term debt					0
Short-term debt	0		0		(35,000,000)
Current liabilities held for sale					(9,008,000)
Other current liabilities	(2,360,000)		(2,360,000)		(13,394,000)
Intercompany payables	(983,866,000)		(983,866,000)		(971,665,000)
Total current liabilities	(986,226,000)		(986,226,000)		(1,029,067,000)
Deferred income taxes	0		0		0
Regulatory cost of removal obligation	0		0		0
Pension and postretirement liabilities	0		0		0
Noncurrent liabilities held for sale					0
Deferred credits and other liabilities	0		0		(169,000)
Total shareholders' equity and liabilities	(1,799,071,000)		(1,799,071,000)		$ (1,811,505,000)
Intersegment Elimination [Member] | Reportable Subsegments [Member]
Segment Reporting Information Profit Loss [Abstract]
Revenues	0	0	0	0
Intersegment Elimination [Member] | Intersubsegment Eliminations [Member]
Segment Reporting Information Profit Loss [Abstract]
Revenues	$ (84,842,000)	$ (82,548,000)	$ (255,609,000)	$ (229,894,000)

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Income from continuing operations	$ 70,808	$ 66,143	$ 346,858	$ 310,692
Income allocated to participating securities	75	100	424	488
Income from continuing operations available to common shareholders	$ 70,733	$ 66,043	$ 346,434	$ 310,204
Income (Loss) from Continuing Operations, Per Basic and Diluted Share	$ 0.67	$ 0.64	$ 3.27	$ 3.01
Income from discontinued operations, net of tax	$ 0	$ 5,050	$ 13,710	$ 5,172
Undistributed Earnings From Discontinued Operations Allocated To Participating Securities	0	6	15	4
Income from discontinued operations available to common shareholders	$ 0	$ 5,044	$ 13,695	$ 5,168
Income (Loss) from Discontinued Operation, Net of Tax, Per Basic and Diluted Share	$ 0	$ 0.05	$ 0.13	$ 0.05
Basic and diluted net income per share	$ 0.67	$ 0.69	$ 3.40	$ 3.06
Weighted Average Number of Shares Outstanding, Basic and Diluted	106,364	103,750	105,862	103,137

Debt (Details)

Debt (Details) - USD ($)	Jan. 03, 2017	Jun. 30, 2017	Sep. 30, 2016	Jun. 30, 2017
Debt Instrument [Line Items]
Debt Instrument Carrying Amount		$ 3,085,000,000	$ 2,460,000,000	$ 3,085,000,000
Debt Instrument, Unamortized Discount (Premium), Net		(4,370,000)	4,270,000	(4,370,000)
Debt Issuance Costs, Net		22,636,000	16,951,000	22,636,000
Current maturities of long-term debt		0	250,000,000	0
Long-term debt		3,066,734,000	2,188,779,000	3,066,734,000
Loss on settlement of interest rate swaps		37,000,000		37,000,000
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		1,500,000,000		1,500,000,000
Long Term Debt Other Disclosures [Abstract]
Term Loan Agreement, Maximum Borrowing Capacity		200,000,000		200,000,000
Term Loan Agreement, Incremental Borrowings		1,000,000		1,000,000
Term Loan Agreement, Amount Outstanding		125,000,000		125,000,000
Commercial Paper		$ 258,600,000	829,800,000	$ 258,600,000
Required by Covenant [Member]
Line Of Credit Facility [Line Items]
Ratio of Total Debt to Total Capital		70.00%		70.00%
Actual [Member]
Line Of Credit Facility [Line Items]
Ratio of Total Debt to Total Capital		47.00%		47.00%
Minimum [Member] | Required by Covenant [Member]
Line Of Credit Facility [Line Items]
Excess of Debt		$ 15,000,000		$ 15,000,000
Maximum [Member] | Required by Covenant [Member]
Line Of Credit Facility [Line Items]
Excess of Debt		100,000,000		100,000,000
Five Year Unsecured Revolving Credit Agreement [Member] | Commercial Paper [Member] | Regulated Operation [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		1,500,000,000	1,250,000,000	1,500,000,000
Line of Credit Facility, Accordion Feature		250,000,000		250,000,000
Line of Credit Facility, Maximum Borrowing Capacity with Accordion Feature		$ 1,750,000,000		1,750,000,000
Five Year Unsecured Revolving Credit Agreement [Member] | Commercial Paper [Member] | Minimum [Member] | Regulated Operation [Member]
Line Of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate		0.00%
Five Year Unsecured Revolving Credit Agreement [Member] | Commercial Paper [Member] | Maximum [Member] | Regulated Operation [Member]
Line Of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.25%
$15 Million Revolving Credit Note [Member] | Unsecured Revolving Credit Note [Member] | Unregulated Operation [Member]
Line Of Credit Facility [Line Items]
Extinguishment of Debt, Amount	$ 15,000,000
$25 Million Bank Loan Agreement [Member] | Unsecured Loan Agreement [Member] | Regulated Operation [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 25,000,000		25,000,000
Line of Credit Facility, Fair Value of Amount Outstanding		0		0
$10 Million Revolving Credit Note [Member] | Unsecured Revolving Credit Note [Member] | Regulated Operation [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		10,000,000		10,000,000
Line of Credit Facility, Remaining Borrowing Capacity		4,100,000		4,100,000
Line of Credit Facility, Fair Value of Amount Outstanding		0		0
$25 Million Uncommitted Facility [Member] | Uncommitted Revolving Credit Facility [Member] | Unregulated Operation [Member]
Line Of Credit Facility [Line Items]
Extinguishment of Debt, Amount	$ 25,000,000
Unsecured Senior Notes Due 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument Carrying Amount		$ 0	$ 250,000,000	$ 0
Debt Instrument, Interest Rate, Stated Percentage		6.35%	6.35%	6.35%
Debt Instrument, Maturity Date		Jun. 15, 2017	Jun. 15, 2017
Unsecured Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument Carrying Amount		$ 450,000,000	$ 450,000,000	$ 450,000,000
Debt Instrument, Interest Rate, Stated Percentage		8.50%	8.50%	8.50%
Debt Instrument, Maturity Date		Mar. 15, 2019	Mar. 15, 2019
Unsecured Senior Notes Due 2034 [Member]
Debt Instrument [Line Items]
Debt Instrument Carrying Amount		$ 200,000,000	$ 200,000,000	$ 200,000,000
Debt Instrument, Interest Rate, Stated Percentage		5.95%	5.95%	5.95%
Debt Instrument, Maturity Date		Oct. 15, 2034	Oct. 15, 2034
Unsecured Senior Notes Due 2041 [Member]
Debt Instrument [Line Items]
Debt Instrument Carrying Amount		$ 400,000,000	$ 400,000,000	$ 400,000,000
Debt Instrument, Interest Rate, Stated Percentage		5.50%	5.50%	5.50%
Debt Instrument, Maturity Date		Jun. 15, 2041	Jun. 15, 2041
Unsecured Senior Notes Due 2043 [Member]
Debt Instrument [Line Items]
Debt Instrument Carrying Amount		$ 500,000,000	$ 500,000,000	$ 500,000,000
Debt Instrument, Interest Rate, Stated Percentage		4.15%	4.15%	4.15%
Debt Instrument, Maturity Date		Jan. 15, 2043	Jan. 15, 2043
Unsecured Senior Notes Due 2044 [Member]
Debt Instrument [Line Items]
Debt Instrument Carrying Amount		$ 750,000,000	$ 500,000,000	$ 750,000,000
Debt Instrument, Interest Rate, Stated Percentage		4.125%	4.125%	4.125%
Debt Instrument, Maturity Date		Oct. 15, 2044	Oct. 15, 2044
Debt Instrument, Interest Rate, Effective Percentage		4.40%		4.40%
Debt Instrument, Increase (Decrease), Net		$ 250,000,000
Medium Term Notes Due 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument Carrying Amount		$ 10,000,000	$ 10,000,000	$ 10,000,000
Debt Instrument, Interest Rate, Stated Percentage		6.67%	6.67%	6.67%
Debt Instrument, Maturity Date		Dec. 15, 2025	Dec. 15, 2025
Unsecured Debentures Due 2028 [Member]
Debt Instrument [Line Items]
Debt Instrument Carrying Amount		$ 150,000,000	$ 150,000,000	$ 150,000,000
Debt Instrument, Interest Rate, Stated Percentage		6.75%	6.75%	6.75%
Debt Instrument, Maturity Date		Jul. 15, 2028	Jul. 15, 2028
Multi-Draw Term Loan Due 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument Carrying Amount		$ 125,000,000	$ 0	$ 125,000,000
Debt Instrument, Maturity Date		Jun. 24, 2019
Unsecured Senior Notes Due 2027 [Member]
Debt Instrument [Line Items]
Debt Instrument Carrying Amount		$ 500,000,000	$ 0	$ 500,000,000
Debt Instrument, Interest Rate, Stated Percentage		3.00%	3.00%	3.00%
Debt Instrument, Maturity Date		Jun. 15, 2027	Jun. 15, 2027
Debt Instrument, Interest Rate, Effective Percentage		3.12%		3.12%
Net Proceeds From Issuance of Debt				$ 753,000,000

Divestitures and Acquisitions36

Divestitures and Acquisitions (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Jan. 01, 2017	Sep. 30, 2016
Disposal Group, Including Discontinued Operation, Additional Disclosures [Abstract]
Disposal Group, Including Discontinued Operation, Cash Purchase Price						$ 38,300
Disposal Group, Including Discontinued Operation, Working Capital Adjustment						109,000
Disposal Group, Including Discontinued Operation, Consideration						147,300
Disposal Group, Including Discontinued Operation, Consideration Placed in Escrow						$ 7,000
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax, Per Diluted Share				$ 0.03
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Income tax expense			$ 3,414	$ 6,841	$ 3,495
Income from discontinued operations, net of tax, before gain on disposal		$ 0	5,050	10,994	5,172
Gain (Loss) on Disposal of Discontinued Operation, Net of Tax				2,716	0
Discontinued Operation, Tax Effect of Gain (Loss) from Disposal of Discontinued Operation		0	0	10,215	0
Net income from discontinued operations		0	5,050	$ 13,710	5,172
Business Acquisition [Line Items]
Business Acquisition, Description of Acquired Entity				On December 20, 2016 , we executed a purchase and sale agreement to acquire the general partnership and limited partnership interests in EnLink North Texas Pipeline, LP (EnLink Pipeline) from EnLink Energy GP, LLC and EnLink Midstream Operating, LP for a cash purchase price of $85 million , plus working capital of $1.1 million . EnLink Pipeline's primary asset was a 140–mile natural gas pipeline located on the north side of the Dallas–Fort Worth Metroplex. The $85 million purchase price has been allocated, based on fair value using observable market inputs, to the net book value of the acquired pipeline.
Natural Gas Marketing Segment [Member] | Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Operating revenues		0	200,213	$ 303,474	728,989
Purchased gas cost		0	184,398	277,554	698,445
Operating expenses		0	7,047	7,874	19,940
Operating income		0	8,768	18,046	10,604
Other nonoperating expense		0	(304)	(211)	(1,937)
Income from discontinued operations before income taxes		0	8,464	17,835	8,667
Income tax expense		0	3,414	6,841	3,495
Income from discontinued operations, net of tax, before gain on disposal				10,994	5,172
Gain (Loss) on Disposal of Discontinued Operation, Net of Tax				2,716	0
Net income from discontinued operations		0	$ 5,050	13,710	5,172
Assets [Abstract]
Total assets of the disposal group		0		0			$ 216,715
Liabilities [Abstract]
Total liabilities of the disposal group		0		0			150,118
Discontinued Operation, Alternative Cash Flow Information [Abstract]
Depreciation and Amortization, Discontinued Operations				185	1,743
Capital Expenditure, Discontinued Operations				0	179
Noncash Change in Commodity Contract Cash Flow Hedges				18,744	$ (33,898)
Natural Gas Marketing Segment [Member] | Discontinued Operations, Held-for-sale or Disposed of by Sale [Member] | Disposal Group Assets and Liabilities Held for Sale [Member]
Assets [Abstract]
Net property, plant and equipment		0		0			11,905
Accounts receivable		0		0			93,551
Gas stored underground		0		0			54,246
Other current assets		0		0			14,711
Goodwill		0		0			16,445
Deferred charges and other assets		0		0			435
Total assets of the disposal group	[1]	0		0			191,293
Liabilities [Abstract]
Accounts payable and accrued liabilities		0		0			72,268
Other current liabilities		0		0			9,640
Deferred credits and other		0		0			316
Total liabilities of the disposal group	[1]	0		0			82,224
Natural Gas Marketing Segment [Member] | Discontinued Operations, Held-for-sale or Disposed of by Sale [Member] | Disposal Group Assets and Liabilities Not Held for Sale [Member]
Assets [Abstract]
Cash		0		0			25,417
Other assets		0		0			5
Liabilities [Abstract]
Intercompany note payable		0		0			35,000
Tax liabilities		0		0			15,471
Intercompany payables		0		0			14,139
Other liabilities		$ 0		0			$ 3,284
Enlink North Texas Pipeline, LP [Member]
Business Acquisition [Line Items]
Business Acquisition, Date of Acquisition Agreement		Dec. 20, 2016
Payments to Acquire Businesses, Gross		$ 85,000		85,000
Other Payments to Acquire Businesses				$ 1,100
[1]	Amounts in the comparative period are classified as current and long term in the statement of financial position.

Shareholders' Equity Components

Shareholders' Equity Components (Details) - USD ($)	9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Shareholders' equity, beginning balance	$ 3,463,059,000
Shareholders' equity, ending balance	3,901,710,000
Shareholders' Equity Other Disclosures [Abstract]
Debt and Equity Securities Authorized for Issuance	2,500,000,000
Debt And Equity Securities Available For Issuance	1,600,000,000
ATM Equity Distribution Offering Price, Maximum Amount	$ 200,000,000
ATM Equity Distribution, Shares Issued	1,303,494
ATM Equity Distribution, Net Proceeds	$ 98,800,000
ATM Equity Distribution, Gross Proceeds	100,000,000
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Shareholders' equity, beginning balance	4,484,000	$ 4,949,000
Other comprehensive income (loss) before reclassifications	1,485,000	(1,417,000)
Amounts reclassified from accumulated other comprehensive income	68,000	(79,000)
Net current-period other comprehensive income (loss)	1,553,000	(1,496,000)
Shareholders' equity, ending balance	6,037,000	3,453,000
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Interest Rate Contract [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Shareholders' equity, beginning balance	(187,524,000)	(88,842,000)
Other comprehensive income (loss) before reclassifications	76,602,000	(88,345,000)
Amounts reclassified from accumulated other comprehensive income	286,000	260,000
Net current-period other comprehensive income (loss)	76,888,000	(88,085,000)
Shareholders' equity, ending balance	(110,636,000)	(176,927,000)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Commodity Contract [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Shareholders' equity, beginning balance	(4,982,000)	(25,437,000)
Other comprehensive income (loss) before reclassifications	9,847,000	(8,612,000)
Amounts reclassified from accumulated other comprehensive income	(4,865,000)	29,290,000
Net current-period other comprehensive income (loss)	4,982,000	20,678,000
Shareholders' equity, ending balance	0	(4,759,000)
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Shareholders' equity, beginning balance	(188,022,000)	(109,330,000)
Other comprehensive income (loss) before reclassifications	87,934,000	(98,374,000)
Amounts reclassified from accumulated other comprehensive income	(4,511,000)	29,471,000
Net current-period other comprehensive income (loss)	83,423,000	(68,903,000)
Shareholders' equity, ending balance	$ (104,599,000)	$ (178,233,000)

Shareholders' Equity AOCI Affec

Shareholders' Equity AOCI Affected Line Item in the Statement of Income (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Operation and maintenance expense		$ (128,690)	$ (131,388)	$ (385,867)	$ (379,073)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest		111,877	101,835	548,832	487,916
Income Tax Expense		(41,069)	(35,692)	(201,974)	(177,224)
Interest charges		(28,498)	(27,679)	(86,472)	(84,775)
Purchased gas cost		(114,176)	(64,583)	(852,975)	(682,265)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) from continuing operations		(113)	(7,619)	4,511	(29,471)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Operation and maintenance expense				(107)	124
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest				(107)	124
Income Tax Expense				39	(45)
Income (loss) from continuing operations				(68)	79
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest		(177)	(12,484)	7,526	(48,425)
Income Tax Expense		64	4,865	(2,947)	18,875
Income (loss) from continuing operations				4,579	(29,550)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Commodity Contract [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Purchased gas cost	[1]	0	(12,347)	7,976	(48,015)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Interest Rate Contract [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest charges		$ (177)	$ (137)	$ (450)	$ (410)
[1]	Amounts are presented as part of income from discontinued operations on the condensed consolidated statements of income.

Interim Pension and Other Pos39

Interim Pension and Other Postretirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Pension Benefits [Member]
Components of net periodic pension cost [Abstract]
Service Cost	$ 5,216	$ 4,698	$ 15,649	$ 14,093
Interest Cost	6,296	7,095	18,890	21,284
Expected return on assets	(6,993)	(6,881)	(20,981)	(20,642)
Amortization of transition (asset)/obligation	0	0	0	0
Amortization of prior service (credit)/cost	(57)	(57)	(173)	(170)
Amortization of actuarial (gain) loss	4,248	3,319	12,746	9,959
Net periodic pension cost	$ 8,710	$ 8,174	$ 26,131	$ 24,524
Defined Benefit Plan Weighted Average Assumptions Used In Calculating Net Periodic Benefit Cost Abstract
Discount Rate	3.73%	4.55%	3.73%	4.55%
Rate of compensation increase	3.50%	3.50%	3.50%	3.50%
Expected return on plan assets	7.00%	7.00%	7.00%	7.00%
Current Year Benefit Plan Contributions [Abstract]
Contributions Actual			$ 5,000
Other Benefits [Member]
Components of net periodic pension cost [Abstract]
Service Cost	$ 3,109	$ 2,705	9,327	$ 8,117
Interest Cost	2,669	3,106	8,009	9,318
Expected return on assets	(1,796)	(1,566)	(5,389)	(4,698)
Amortization of transition (asset)/obligation	0	21	0	62
Amortization of prior service (credit)/cost	(411)	(411)	(1,233)	(1,233)
Amortization of actuarial (gain) loss	(706)	(541)	(2,120)	(1,625)
Net periodic pension cost	$ 2,865	$ 3,314	$ 8,594	$ 9,941
Defined Benefit Plan Weighted Average Assumptions Used In Calculating Net Periodic Benefit Cost Abstract
Discount Rate	3.73%	4.55%	3.73%	4.55%
Expected return on plan assets	4.45%	4.45%	4.45%	4.45%
Current Year Benefit Plan Contributions [Abstract]
Contributions Actual			$ 9,900
Other Benefits [Member] | Minimum [Member]
Current Year Benefit Plan Contributions [Abstract]
Defined Benefit Plan, Expected Contributions in Current Fiscal Year			10,000
Other Benefits [Member] | Maximum [Member]
Current Year Benefit Plan Contributions [Abstract]
Defined Benefit Plan, Expected Contributions in Current Fiscal Year			$ 20,000

Commitments and Contingencies C

Commitments and Contingencies Commitments and Contingencies (Details) - Inventories Under Indexed Contracts [Member] - Mid-Tex Division [Member]	Jun. 30, 2017MMcf
Long-term Purchase Commitment [Line Items]
Long Term Purchase Commitment Minimum Quantity Required Within One Year	53,200
Long Term Purchase Commitment Minimum Quantity Required One To Three Years	37,600
Long Term Purchase Commitment Minimum Quantity Required After Three Years	400

Financial Instruments Descripti

Financial Instruments Descriptions (Details) $ in Millions	3 Months Ended	9 Months Ended
	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)MMcf	Jun. 30, 2016USD ($)
General Discussion Of Derivative Instruments And Hedging Activities [Abstract]
Minimum Hedge Percentage Of Anticipated Heating Season Gas		25.00%
Maximum Hedge Percentage Of Anticipated Heating Season Gas		50.00%
Hedge Percentage Of Actual Heating Season Gas		27.00%
Hedge Volume Of Actual Heating Season Gas | MMcf		16,200
Gain on Discontinuation of Cash Flow Hedge		$ 10.6
Accumulated Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Interest Rate Agreements, Realized Gain (Loss), Net of Tax		(41.5)
Gain (Loss) On Hedge Ineffectiveness	$ 13.6	$ 3.4	$ 18.1
Regulated Segments Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate		37.00%	37.00%
Nonregulated Segment Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate		39.00%	39.00%
Gain (Loss) On Derivative Instruments Not Designated Hedges Net Pretax	$ 1.9	$ 6.8	$ (2.8)
Interest Rate Hedges, Senior Notes 2019 Issuance [Member]
Derivative [Line Items]
Notional Amount of Interest Rate Cash Flow Hedge Derivatives		450
Anticipated Debt Issuance, Amount		$ 450
Derivative, Average Forward Interest Rate		3.78%

Financial Instruments Commodity

Financial Instruments Commodity Contract Volume (Details)	Jun. 30, 2017MMcf
Nondesignated [Member]
Commodity Contract Outstanding Volumes [Line Items]
Investment Contract Volume	18,833

Financial Instruments Balance S

Financial Instruments Balance Sheet Location (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Sep. 30, 2016
Derivatives Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 3,228	$ 44,141
Derivative Asset, Contract Netting	0	(39,290)
Derivative Asset, Net of Contract Netting	3,228	4,851
Derivative, Collateral, Right to Reclaim Cash	0	6,775
Derivative Asset	3,228	11,626
Derivative Liability, Fair Value, Gross Liability	(109,372)	(323,684)
Derivative Liability, Contract Netting	0	(39,290)
Derivative Liability, Net of Contract Netting	(109,372)	(284,394)
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	(43,575)
Derivative Liability	(109,372)	(240,819)
Designated As Hedging Instrument [Member]
Derivatives Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	8,790
Derivative Liability, Fair Value, Gross Liability	(108,860)	(292,171)
Designated As Hedging Instrument [Member] | Other Current Assets [Member] | Interest Rate Contract [Member]
Derivatives Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		0
Designated As Hedging Instrument [Member] | Other Current Assets [Member] | Commodity Contract [Member]
Derivatives Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		6,612
Designated As Hedging Instrument [Member] | Deferred Charges And Other Assets [Member] | Interest Rate Contract [Member]
Derivatives Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Designated As Hedging Instrument [Member] | Deferred Charges And Other Assets [Member] | Commodity Contract [Member]
Derivatives Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		2,178
Designated As Hedging Instrument [Member] | Other Current Liabilities [Member] | Interest Rate Contract [Member]
Derivatives Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability		(68,481)
Designated As Hedging Instrument [Member] | Other Current Liabilities [Member] | Commodity Contract [Member]
Derivatives Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability		(21,903)
Designated As Hedging Instrument [Member] | Deferred Credits And Other Liabilities [Member] | Interest Rate Contract [Member]
Derivatives Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	(108,860)	(198,008)
Designated As Hedging Instrument [Member] | Deferred Credits And Other Liabilities [Member] | Commodity Contract [Member]
Derivatives Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability		(3,779)
Nondesignated [Member]
Derivatives Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	3,228	35,351
Derivative Liability, Fair Value, Gross Liability	(512)	(31,513)
Nondesignated [Member] | Other Current Assets [Member] | Commodity Contract [Member]
Derivatives Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	2,960	21,186
Nondesignated [Member] | Deferred Charges And Other Assets [Member] | Commodity Contract [Member]
Derivatives Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	268	14,165
Nondesignated [Member] | Other Current Liabilities [Member] | Commodity Contract [Member]
Derivatives Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	(230)	(18,812)
Nondesignated [Member] | Deferred Credits And Other Liabilities [Member] | Commodity Contract [Member]
Derivatives Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	$ (282)	$ (12,701)

Financial Instruments Fair Valu

Financial Instruments Fair Value Hedges and Cash Flow Hedges (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Effect of Fair Value Hedges on Results of Operations [Abstract]
Commodity contracts	$ 0	$ (22,146)	$ (9,567)	$ (11,808)
Fair value adjustment for natural gas inventory designated as the hedged item	0	35,630	12,858	29,852
Total (increase) decrease to purchased gas cost	0	13,484	3,291	18,044
Basis ineffectiveness	0	(684)	(597)	(1,490)
Timing ineffectiveness	0	14,168	3,888	19,534
Summary of Cash Flow Hedge Activity [Abstract]
Gain (loss) reclassified from AOCI into purchased gas cost for effective portion of commodity contracts	0	(12,347)	(2,612)	(48,015)
Gain (loss) arising from ineffective portion of commodity contracts	0	66	111	84
Gain (Loss) on Discontinuation of Cash Flow Hedge	0	0	10,579	0
Total impact on purchased gas cost	0	(12,281)	8,078	(47,931)
Loss on settled Treasury Lock agreements reclassified from AOCI into interest expense	(177)	(137)	(450)	(410)
Total Impact from Cash Flow Hedges	$ (177)	$ (12,418)	$ 7,628	$ (48,341)

Financial Instruments Other Com

Financial Instruments Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Interest rate agreements fair value	$ (18,669)	$ (39,337)	$ 76,602	$ (88,345)
Forward commodity contracts fair value	0	10,573	9,847	(8,612)
Interest rate agreements	113	87	286	260
Forward commodity contracts	0	7,532	(4,865)	29,290
Total other comprehensive income (loss) from hedging, net of tax	(18,556)	$ (21,145)	81,870	$ (67,407)
Expected Earnings [Line Items]
Expected Recognition in Earnings of Deferred Gain (Losses), Interest Rate Agreements	(41,510)		(41,510)
Next Twelve Months [Member]
Expected Earnings [Line Items]
Expected Recognition in Earnings of Deferred Gain (Losses), Interest Rate Agreements	(1,509)		(1,509)
Thereafter [Member]
Expected Earnings [Line Items]
Expected Recognition in Earnings of Deferred Gain (Losses), Interest Rate Agreements	$ (40,001)		$ (40,001)

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($)	Jun. 30, 2017	Sep. 30, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	$ 0	$ (32,515,000)
Derivative Asset	3,228,000	11,626,000
Hedged portion of gas stored underground		52,578,000
Available-for-sale Securities	89,611,000	72,701,000
Total assets	92,839,000	136,905,000
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	0	(82,865,000)
Derivative Liability	109,372,000	240,819,000
Derivative, Cash Collateral		50,400,000
Cash Held In Margin Accounts Classified Current Risk Management Asset	0	6,775,000
Cash Held In Margin Accounts Offset Current Risk Management Liabilities	0	43,575,000
Additional Fair Value Elements [Abstract]
Debt Instrument Carrying Amount	3,085,000,000	2,460,000,000
Debt Instrument Fair Value	3,388,003,000	2,844,990,000
Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities	39,406,000	38,677,000
Fixed Income Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities	15,892,000
Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities	31,429,000	31,394,000
Money Market Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities	2,884,000	2,630,000
Fair Value Inputs Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	0	0
Hedged portion of gas stored underground		52,578,000
Available-for-sale Securities	55,298,000	38,677,000
Total assets	55,298,000	91,255,000
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	0	0
Fair Value Inputs Level 1 [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities	39,406,000	38,677,000
Fair Value Inputs Level 1 [Member] | Fixed Income Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities	15,892,000
Fair Value Inputs Level 1 [Member] | Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value Inputs Level 1 [Member] | Money Market Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value Inputs Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	3,228,000	44,141,000
Hedged portion of gas stored underground		0
Available-for-sale Securities	34,313,000	34,024,000
Total assets	37,541,000	78,165,000
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	109,372,000	323,684,000
Fair Value Inputs Level 2 [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value Inputs Level 2 [Member] | Fixed Income Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities	0
Fair Value Inputs Level 2 [Member] | Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities	31,429,000	31,394,000
Fair Value Inputs Level 2 [Member] | Money Market Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities	2,884,000	2,630,000
Fair Value Inputs Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	0	0
Hedged portion of gas stored underground		0
Available-for-sale Securities	0	0
Total assets	0	0
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	0	0
Fair Value Inputs Level 3 [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value Inputs Level 3 [Member] | Fixed Income Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities	0
Fair Value Inputs Level 3 [Member] | Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value Inputs Level 3 [Member] | Money Market Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities	$ 0	$ 0

Fair Value Measurements Availab

Fair Value Measurements Available-For-Sale Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Sep. 30, 2016
Schedule Of Available For Sale Securities [Line Items]
Available For Sale Securities Amortized Cost	$ 80,036	$ 65,572
Gross Unrealized Gain	9,658	7,729
Gross Unrealized Loss	(83)	(600)
Fair value	89,611	72,701
Available-for-sale Securities, Other Disclosure Items [Abstract]
Available-for-sale Securities, Supplemental Executive Benefit Plans	42,300	41,300
Equity Funds Domestic [Member]
Schedule Of Available For Sale Securities [Line Items]
Available For Sale Securities Amortized Cost	25,236	26,692
Gross Unrealized Gain	7,749	6,419
Gross Unrealized Loss	(17)	(590)
Fair value	32,968	32,521
Equity Funds Foreign [Member]
Schedule Of Available For Sale Securities [Line Items]
Available For Sale Securities Amortized Cost	4,581	4,954
Gross Unrealized Gain	1,857	1,202
Gross Unrealized Loss	0	0
Fair value	6,438	6,156
Fixed Income Funds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available For Sale Securities Amortized Cost	15,928
Gross Unrealized Gain	0
Gross Unrealized Loss	(36)
Fair value	15,892
Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available For Sale Securities Amortized Cost	31,407	31,296
Gross Unrealized Gain	52	108
Gross Unrealized Loss	(30)	(10)
Fair value	31,429	31,394
Money Market Funds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available For Sale Securities Amortized Cost	2,884	2,630
Gross Unrealized Gain	0	0
Gross Unrealized Loss	0	0
Fair value	$ 2,884	$ 2,630