Cencora (COR) 10-Q 2 May 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Mar. 31, 2019	Apr. 30, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	AMERISOURCEBERGEN CORP
Entity Central Index Key	0001140859
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--09-30
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		210,176,951
Trading Symbol	abc

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2019	Sep. 30, 2018
Current assets:
Cash and cash equivalents	$ 2,875,750	$ 2,492,516
Accounts receivable, less allowances for returns and doubtful accounts: $1,044,391 as of March 31, 2019 and $1,036,333 as of September 30, 2018	12,222,271	11,314,226
Inventories (Note 1)	11,373,730	11,918,508
Right to recover asset (Note 1)	977,860	0
Prepaid expenses and other	172,572	169,122
Total current assets	27,622,183	25,894,372
Property and equipment, at cost:
Land	44,258	39,875
Buildings and improvements	1,039,260	1,086,909
Machinery, equipment, and other	2,301,431	2,281,124
Total property and equipment	3,384,949	3,407,908
Less accumulated depreciation	(1,526,082)	(1,515,484)
Property and equipment, net	1,858,867	1,892,424
Goodwill	6,699,681	6,664,272
Other intangible assets	2,355,997	2,947,828
Other assets	273,582	270,942
TOTAL ASSETS	38,810,310	37,669,838
Current liabilities:
Accounts payable	28,189,390	26,836,873
Accrued expenses and other	739,536	881,157
Short-term debt	282,973	151,657
Total current liabilities	29,211,899	27,869,687
Long-term debt	4,009,500	4,158,532
Long-term financing obligation	350,400	352,296
Accrued income taxes	273,662	299,600
Deferred income taxes	1,857,201	1,829,410
Other liabilities	69,317	110,352
Stockholders’ equity:
Common stock, $0.01 par value - authorized, issued, and outstanding: 600,000,000 shares, 284,559,858 shares, and 210,167,489 shares as of March 31, 2019, respectively, and 600,000,000 shares, 283,588,463 shares, and 213,217,882 shares as of September 30, 2018, respectively	2,846	2,836
Additional paid-in capital	4,790,507	4,715,473
Retained earnings	3,969,459	3,720,582
Accumulated other comprehensive loss	(85,142)	(79,253)
Treasury stock, at cost: 74,392,369 shares as of March 31, 2019 and 70,370,581 shares as of September 30, 2018	(5,756,455)	(5,426,814)
Total AmerisourceBergen Corporation stockholders' equity	2,921,215	2,932,824
Noncontrolling interest	117,116	117,137
Total equity	3,038,331	3,049,961
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 38,810,310	$ 37,669,838

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Sep. 30, 2018
Statement of Financial Position [Abstract]
Allowances for returns and doubtful accounts	$ 1,044,391	$ 1,036,333
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, authorized (shares)	600,000,000	600,000,000
Common stock, issued (shares)	284,559,858	283,588,463
Common stock, outstanding (shares)	210,167,489	213,217,882
Treasury stock (shares)	74,392,369	70,370,581

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Revenue	$ 43,319,602	$ 41,033,858	$ 88,712,054	$ 81,500,190
Cost of goods sold	41,894,846	39,778,175	85,989,718	79,131,855
Gross profit	1,424,756	1,255,683	2,722,336	2,368,335
Operating expenses:
Distribution, selling, and administrative	628,036	617,426	1,284,621	1,175,948
Depreciation	75,219	72,718	150,581	137,625
Amortization	48,547	46,670	95,685	86,899
Employee severance, litigation, and other	55,389	37,449	96,061	67,470
Impairment of long-lived assets	570,000	0	570,000	0
Operating income	47,565	481,420	525,388	900,393
Other (income) loss	(14,494)	29,123	(11,397)	29,447
Interest expense, net	43,275	48,637	85,445	84,501
Loss on consolidation of equity investments	0	42,328	0	42,328
Loss on early retirement of debt	0	0	0	23,766
Income before income taxes	18,784	361,332	451,340	720,351
Income tax (benefit) expense	(9,289)	79,172	31,514	(423,662)
Net income	28,073	282,160	419,826	1,144,013
Net (income) loss attributable to noncontrolling interest	(938)	5,295	961	5,295
Net income attributable to AmerisourceBergen Corporation	$ 27,135	$ 287,455	$ 420,787	$ 1,149,308
Earnings per share:
Basic (usd per share)	$ 0.13	$ 1.31	$ 1.99	$ 5.25
Diluted (usd per share)	$ 0.13	$ 1.29	$ 1.97	$ 5.19
Weighted average common shares outstanding:
Basic (shares)	210,934	219,200	211,503	218,763
Diluted (shares)	212,563	222,303	213,275	221,565
Cash dividends declared per share of common stock (usd per share)	$ 0.4	$ 0.38	$ 0.8	$ 0.76

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 28,073	$ 282,160	$ 419,826	$ 1,144,013
Other comprehensive income (loss)
Foreign currency translation adjustments	7,414	6,831	(3,960)	6,425
Loss on consolidation of equity investments	0	45,941	0	45,941
Other	225	60	113	(22)
Total other comprehensive income (loss)	7,639	52,832	(3,847)	52,344
Total comprehensive income	35,712	334,992	415,979	1,196,357
Comprehensive income attributable to noncontrolling interest	(836)	5,295	(1,081)	5,295
Comprehensive income attributable to AmerisourceBergen Corporation	$ 34,876	$ 340,287	$ 414,898	$ 1,201,652

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock	Noncontrolling Interest
Beginning balance at Sep. 30, 2017	$ 2,064,461	$ 2,806	$ 4,517,635	$ 2,395,218	$ (95,850)	$ (4,755,348)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidation of variable interest entity	181,341						181,341
Net income (loss)	1,144,013			1,149,308			(5,295)
Other comprehensive income (loss)	52,344				52,344
Cash dividends	(167,533)			(167,533)
Exercises of stock options	115,236	22	115,214
Share-based compensation expense	44,208		44,208
Common stock purchases for employee stock purchase plan	(202)		(202)
Purchases of common stock	(60,208)					(60,208)
Employee tax withholdings related to restricted share vesting	(7,507)					(7,507)
Other	(2,557)	3	(2,560)
Ending balance at Mar. 31, 2018	3,363,596	2,831	4,674,295	3,376,993	(43,506)	(4,823,063)	176,046
Beginning balance at Dec. 31, 2017	2,874,582	2,814	4,579,809	3,173,516	(96,338)	(4,785,219)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidation of variable interest entity	181,341						181,341
Net income (loss)	282,160			287,455			(5,295)
Other comprehensive income (loss)	52,832				52,832
Cash dividends	(83,978)			(83,978)
Exercises of stock options	85,662	16	85,646
Share-based compensation expense	11,600		11,600
Common stock purchases for employee stock purchase plan	(202)		(202)
Purchases of common stock	(37,712)					(37,712)
Employee tax withholdings related to restricted share vesting	(132)					(132)
Other	(2,557)	1	(2,558)
Ending balance at Mar. 31, 2018	3,363,596	2,831	4,674,295	3,376,993	(43,506)	(4,823,063)	176,046
Beginning balance at Sep. 30, 2018	3,049,961	2,836	4,715,473	3,720,582	(79,253)	(5,426,814)	117,137
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	419,826			420,787			(961)
Other comprehensive income (loss)	(3,847)				(5,889)		2,042
Cash dividends	(170,428)			(170,428)
Exercises of stock options	37,590	8	37,582
Share-based compensation expense	37,869		37,869
Purchases of common stock	(323,974)					(323,974)
Employee tax withholdings related to restricted share vesting	(5,667)					(5,667)
Other	(415)	2	(417)
Ending balance at Mar. 31, 2019	3,038,331	2,846	4,790,507	3,969,459	(85,142)	(5,756,455)	117,116
Beginning balance at Dec. 31, 2018	3,164,733	2,842	4,769,595	4,027,217	(92,883)	(5,658,318)	116,280
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	28,073			27,135			938
Other comprehensive income (loss)	7,639				7,741		(102)
Cash dividends	(84,893)			(84,893)
Exercises of stock options	15,190	4	15,186
Share-based compensation expense	6,101		6,101
Purchases of common stock	(98,124)					(98,124)
Employee tax withholdings related to restricted share vesting	(13)					(13)
Other	(375)	0	(375)
Ending balance at Mar. 31, 2019	$ 3,038,331	$ 2,846	$ 4,790,507	$ 3,969,459	$ (85,142)	$ (5,756,455)	$ 117,116

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Statement of Stockholders' Equity [Abstract]
Cash dividends (in dollars per share)	$ 0.40	$ 0.38	$ 0.80	$ 0.76

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
OPERATING ACTIVITIES
Net income	$ 419,826	$ 1,144,013
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation, including amounts charged to cost of goods sold	171,789	142,187
Amortization, including amounts charged to interest expense	100,040	95,047
Provision (benefit) for doubtful accounts	10,892	(1,539)
Provision (benefit) for deferred income taxes	24,949	(798,435)
Share-based compensation	37,869	44,208
LIFO credit	(69,834)	0
Impairment of non-customer note receivable	570,000	0
Gain on sale of an equity investment	(13,692)	0
Impairment of non-customer note receivable	0	30,000
Loss on consolidation of equity investments	0	42,328
Loss on early retirement of debt	0	23,766
Other	(11,610)	7,729
Changes in operating assets and liabilities, excluding the effects of acquisitions:
Accounts receivable	(880,805)	(590,386)
Inventories	(420,190)	(805,164)
Prepaid expenses and other assets	(16,914)	(89,601)
Accounts payable	1,350,728	384,378
Income taxes payable	(60,048)	262,495
Accrued expenses and other liabilities	(109,668)	31,732
NET CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES	1,103,332	(77,242)
INVESTING ACTIVITIES
Capital expenditures	(161,488)	(168,816)
Cost of acquired companies, net of cash acquired	(52,398)	(777,085)
Other	2,659	10,479
NET CASH USED IN INVESTING ACTIVITIES	(211,227)	(935,422)
FINANCING ACTIVITIES
Senior notes and other loan borrowings	439,181	1,236,483
Senior notes and other loan repayments	(456,591)	(434,480)
Borrowings under revolving and securitization credit facilities	541,066	24,430,951
Repayments under revolving and securitization credit facilities	(539,673)	(24,412,230)
Payment of premium on early retirement of debt	0	(22,348)
Purchases of common stock	(347,959)	(60,208)
Exercises of stock options	37,590	115,236
Cash dividends on common stock	(170,428)	(167,533)
Tax withholdings related to restricted share vesting	(5,667)	(7,507)
Other	(6,390)	(9,456)
NET CASH (USED IN) PROVIDED BY FINANCING ACTIVITIES	(508,871)	668,908
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	383,234	(343,756)
Cash and cash equivalents at beginning of period	2,492,516	2,435,115
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 2,875,750	$ 2,091,359

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accompanying financial statements present the consolidated financial position, results of operations, and cash flows of AmerisourceBergen Corporation and its subsidiaries, including less than wholly-owned subsidiaries in which AmerisourceBergen Corporation has a controlling financial interest (the "Company"), as of the dates and for the periods indicated. All intercompany accounts and transactions have been eliminated in consolidation. The accompanying unaudited consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles ("GAAP") for interim financial information, the instructions to Form 10-Q, and Rule 10-01 of Regulation S-X. In the opinion of management, all adjustments (consisting only of normal recurring accruals, except as otherwise disclosed herein) considered necessary to present fairly the financial position as of March 31, 2019 and the results of operations and cash flows for the interim periods ended March 31, 2019 and 2018 have been included. Certain information and footnote disclosures normally included in financial statements presented in accordance with U.S. GAAP, but which are not required for interim reporting purposes, have been omitted. The accompanying unaudited consolidated financial statements should be read in conjunction with the financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended September 30, 2018 . The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect amounts reported in the financial statements and accompanying notes. Actual amounts could differ from these estimated amounts. Recently Adopted Accounting Pronouncements In May 2014, the Financial Accounting Standards Board ("FASB") issued ASU No. 2014-09, "Revenue from Contracts with Customers (Topic 606)" ("ASU 2014-09"). ASU 2014-09 supersedes the revenue recognition requirements in Accounting Standards Codification ("ASC") 605 - "Revenue Recognition" and most industry-specific guidance throughout the Codification. ASU 2014-09 outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers. The standard's core principle is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 was originally scheduled to be effective for annual reporting periods beginning after December 15, 2016, including interim periods within those reporting periods. In July 2015, the FASB deferred the effective date of ASU 2014-09 by one year. In March 2016, the FASB issued ASU No. 2016-08, "Revenue from Contracts with Customers (Topic 606) - Principal versus Agent Considerations" ("ASU 2016-08"), which clarifies the implementation guidance for principal versus agent considerations in ASU 2014-09. In April 2016, the FASB issued ASU No. 2016-10, "Revenue from Contracts with Customers (Topic 606) - Identifying Performance Obligations and Licensing" ("ASU 2016-10"), which amends the guidance in ASU 2014-09 related to identifying performance obligations and accounting for licenses of intellectual property. The Company must adopt ASU 2016-08 and ASU 2016-10 with ASU 2014-09, collectively ASC 606. The Company adopted ASC 606 as of October 1, 2018 on a modified retrospective basis for all open contracts as of October 1, 2018. The adoption had an immaterial impact on the Company’s October 1, 2018 retained earnings and will not have a material impact on the Company's revenues, results of operations, or cash flows. The Company did not record any material contract assets, contract liabilities, or deferred contract costs in its Consolidated Balance Sheet upon adoption. The Company's revenues are primarily generated from the distribution of pharmaceutical products. The Company also generates revenues from global commercialization services, which include clinical trial support, post-approval and commercialization support, and global specialty transportation and logistics for the biopharmaceutical industry. See Note 13 for the Company's disaggregated revenue. The Company recognizes revenue related to the distribution of products at a point in time when title and control transfers to customers and there is no further obligation to provide services related to such products. Service revenue is recognized over the period that services are provided to the customer. The Company is generally the principal in a transaction; therefore, revenue is primarily recorded on a gross basis. When the Company is the principal in a transaction, it has determined that it controls the ability to direct the use of the product or service prior to the transfer to a customer, it is primarily responsible for fulfilling the promise to provide the product or service to its customer, it has discretion in establishing pricing, and it controls the relationship with the customer. Revenue is recognized at the amount of consideration expected to be received, which is generally based on a purchase order, and is net of estimated sales returns and allowances, other customer incentives, and sales tax. The Company’s customer sales return policy generally allows customers to return products only if the products can be resold at full value or returned to suppliers for full credit. The Company records an accrual for estimated customer sales returns at the time of sale to the customer based upon historical return trends. As of March 31, 2019 and September 30, 2018, the Company’s accrual for estimated customer sales returns was $977.9 million and $988.8 million , respectively. In fiscal 2019, due to the adoption of ASC 606, the Company records an asset for the right to recover products from its customers in Right to Recover Asset on its Consolidated Balance Sheet. The Company's asset for the right to recover products from its customers was in Inventories on its Consolidated Balance Sheet as of September 30, 2018 and for all prior periods. The Company elected the practical expedient to expense costs to obtain a contract when incurred when the amortization period would have been one year or less. Additionally, the Company elected the practical expedients to not disclose the value of unsatisfied performance obligations for (i) contracts with an original expected length of one year or less, (ii) contracts for which the Company recognizes revenue at the amount to which it has the right to invoice for services performed, and (iii) for contracts for which the variable consideration is allocated entirely to a wholly unsatisfied performance obligation or to a wholly unsatisfied promise to transfer a distinct good or service that forms part of a single performance obligation. Recently Issued Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02, "Leases (Topic 842)" ("ASU 2016-02"). ASU 2016-02 aims to increase transparency and comparability across organizations by requiring lease assets and lease liabilities to be recognized on the balance sheet as well as key information to be disclosed regarding lease arrangements. ASU 2016-02 is effective for annual reporting periods beginning after December 15, 2018 and interim periods within those fiscal years. Entities are permitted to adopt the standard early, and a modified retrospective application is required. The Company anticipates that the adoption of this new accounting standard will have a material impact on the Company's Consolidated Balance Sheets. However, the Company continues to evaluate the impact of adopting this new accounting standard, and, therefore, cannot reasonably estimate the impact on the results of operations or cash flows at this time. The Company has begun the process of implementing the adoption of this standard, including the implementation of new lease accounting software, policies, processes, and controls. The Company will adopt this standard in the first quarter of fiscal 2020. As of March 31, 2019 , there were no other recently-issued accounting standards that may have a material impact on the Company’s financial position, results of operations, or cash flows upon their adoption.

Acquisitions and Investments

Acquisitions and Investments	6 Months Ended
	Mar. 31, 2019
Business Combinations [Abstract]
Acquisitions and Investments	Acquisitions and Investments NEVSCO In December 2017, the Company acquired Northeast Veterinary Supply Company ("NEVSCO") for $70.0 million . NEVSCO was an independent, regional distributor of veterinary pharmaceuticals and medical supplies serving primarily the northeast region of the United States and strengthens MWI Animal Health's ("MWI") support of independent veterinary practices and provides even greater value and care to current and future animal health customers. NEVSCO is included within the MWI operating segment. The purchase price was allocated to the underlying assets acquired and liabilities assumed based upon their fair values on the date of the acquisition. The purchase price exceeded the fair value of the net tangible and intangible assets acquired by $30.4 million , which was allocated to goodwill. The fair value of accounts receivable, inventory, and accounts payable and accrued expenses acquired was $8.5 million , $6.7 million , and $2.9 million , respectively. The fair value of the intangible assets acquired of $29.8 million primarily consisted of customer relationships, which the Company is amortizing over its estimated useful life of 15 years . Goodwill and intangible assets resulting from the acquisition are deductible for income tax purposes. H.D. Smith In January 2018, the Company acquired H.D. Smith Holding Company ("H.D. Smith") for $815.0 million . The Company funded the acquisition through the issuance of new long-term debt. H.D. Smith was the largest independent pharmaceutical wholesaler in the United States and provides full-line distribution of brand, generic, and specialty drugs, as well as high-value services and solutions for manufacturers and healthcare providers. H.D. Smith's customers include retail pharmacies, specialty pharmacies, long-term care facilities, institutional/hospital systems, and independent physicians and clinics. The acquisition strengthens the Company's core business, expands and enhances its strategic scale in pharmaceutical distribution, and expands the Company's support for independent community pharmacies. H.D. Smith is included within the Pharmaceutical Distribution Services reportable segment. The purchase price was allocated to the underlying assets acquired and liabilities assumed based upon their fair values on the date of the acquisition. The purchase price exceeded the fair value of the net tangible and intangible assets acquired by $499.9 million , which was allocated to goodwill. The fair value of accounts receivable, inventory, and accounts payable and accrued expenses acquired was $163.1 million , $350.7 million , and $366.1 million , respectively. The fair value of the intangible assets acquired of $167.8 million consisted of customer relationships of $156.6 million and a tradename of $11.2 million . The Company is amortizing the fair value of the customer relationships and the tradename over their estimated useful lives of 12 years and 2 years, respectively. The Company established a deferred tax liability of $60.6 million primarily in connection with the intangible assets acquired. Goodwill and intangible assets resulting from the acquisition are not deductible for income tax purposes. Profarma and Specialty Joint Venture As of September 30, 2017, the Company held a noncontrolling ownership interest in Profarma Distribuidora de Produtos Farmacêuticos S.A. ("Profarma"), a leading pharmaceutical wholesaler in Brazil, and an ownership interest in a joint venture with Profarma to provide specialty distribution and services to the Brazilian marketplace (the "specialty joint venture"). The Company had accounted for these interests as equity method investments, which were reported in Other Assets on the Company's Consolidated Balance Sheets. In January 2018, the Company invested an additional $62.5 million in Profarma and an additional $15.6 million in the specialty joint venture to increase its ownership interests to 38.2% and 64.5% , respectively. In connection with the additional investment in Profarma, the Company received substantial governance rights, thereby requiring it to begin consolidating the operating results of Profarma as of March 31, 2018 (see Note 3 ). The Company also began to consolidate the operating results of the specialty joint venture as of March 31, 2018 due to its majority ownership interest. In September 2018, the Company made an additional investment of $23.6 million in the specialty joint venture to increase its ownership interest to 89.9% . Profarma and the specialty joint venture are included within the Pharmaceutical Distribution reportable segment and Other, respectively. The fair value of Profarma, including the noncontrolling interest, was determined based upon an agreed-upon stock price and was allocated to the underlying assets and liabilities consolidated based upon their fair values at the time of the January 2018 investment. The fair value of Profarma upon obtaining control exceeded the fair value of the net tangible and intangible assets consolidated by $142.0 million , which was allocated to goodwill. The fair value of accounts receivable, inventory, accounts payable and accrued expenses was $160.1 million , $190.5 million , and $167.7 million , respectively. The Company consolidated short-term debt and long-term debt of $209.9 million and $12.4 million , respectively, cash of $150.8 million , and recorded a noncontrolling interest of $168.0 million . The estimated fair value of the intangible assets consolidated of $84.6 million consisted of customer relationships of $25.9 million and a tradename of $58.7 million . The Company is amortizing the customer relationships over its estimated useful life of 15 years and the tradenames over their estimated useful lives of between 15 years and 25 years. The Company established a deferred tax liability of $50.1 million primarily in connection with the intangible assets that were recognized. Goodwill and intangible assets resulting from the consolidation are not deductible for income tax purposes. The fair value of the specialty joint venture was determined based upon the cost of the incremental ownership percentage acquired from the January 2018 investment and was allocated to the underlying assets and liabilities consolidated based upon their fair values at the time of the January 2018 investment. The fair value of the specialty joint venture exceeded the fair value of the net tangible and intangible assets consolidated by $3.5 million , which was allocated to goodwill. The fair value of accounts receivable, inventory, accounts payable and accrued expenses was $65.0 million , $29.1 million , and $54.3 million , respectively. The Company consolidated short-term debt and cash of $32.7 million and $28.9 million , respectively. The estimated fair value of the intangible assets consolidated of $4.6 million is being amortized over its estimated useful life of 15 years. Goodwill and intangible assets resulting from the consolidation are not deductible for income tax purposes. In connection with the incremental January 2018 Brazil investments, the Company adjusted the carrying values of its previously held equity interests in Profarma and the specialty joint venture to equal their fair values, which were determined to be $103.1 million and $31.2 million , respectively. These represent Level 2 nonrecurring fair value measurements. The adjustments resulted in a pretax loss of $42.3 million in the three and six months ended March 31, 2018 and were comprised of foreign currency translation adjustments from Accumulated Other Comprehensive Loss of $45.9 million , a $12.4 million gain on the remeasurement of Profarma's previously held equity interest, and an $8.8 million loss on the remeasurement of the specialty joint venture's previously held equity interest.

Variable Interest Entity

Variable Interest Entity	6 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entity	Variable Interest Entity As discussed in Note 2 , the Company made an additional investment in Profarma in January 2018. In connection with this investment, the Company obtained substantial governance rights, allowing it to direct the activities that significantly impact Profarma’s economic performance. As such, the Company consolidated the operating results of Profarma in its consolidated financial statements as of and for the periods ended March 31, 2019 and September 30, 2018. The Company is not obligated to provide future financial support to Profarma. The following assets and liabilities of Profarma are included in the Company's Consolidated Balance Sheets: (in thousands) March 31, September 30, Cash and cash equivalents $ 16,711 $ 26,801 Accounts receivables, net 149,223 144,646 Inventories 170,963 168,931 Prepaid expenses and other 59,757 61,924 Property and equipment, net 32,824 32,667 Goodwill 82,309 82,309 Other intangible assets 78,219 80,974 Other long-term assets 8,214 8,912 Total assets $ 598,220 $ 607,164 Accounts payable $ 156,666 $ 150,102 Accrued expenses and other 49,847 37,195 Short-term debt 118,133 115,461 Long-term debt 38,182 39,704 Deferred income taxes 43,233 46,137 Other long-term liabilities 6,539 31,988 Total liabilities $ 412,600 $ 420,587 Profarma's assets can only be used to settle its obligations, and its creditors do not have recourse to the general credit of the Company.

Income Taxes

Income Taxes	6 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Tax Cuts and Jobs Act On December 22, 2017, the Tax Cuts and Jobs Act (the "2017 Tax Act") was signed into law. The 2017 Tax Act includes a broad range of tax reform provisions affecting businesses, including lower corporate tax rates, changes in business deductions, and international tax provisions. In response to the 2017 Tax Act, the U.S. Securities and Exchange Commission staff issued Staff Accounting Bulletin No. 118 ("SAB 118") to address the application of U.S. GAAP in situations where a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the 2017 Tax Act. SAB 118 provides that the measurement period is complete when a company's accounting is complete, and that measurement period shall not extend beyond one year from the enactment date. The Company completed the accounting for the effects of the 2017 Tax Act in the fiscal quarter ended December 31, 2018 and recognized an income tax benefit of $37.0 million related to a decrease in its tax on historical foreign earnings and profits through December 31, 2017 (the "transition tax"). This measurement period adjustment favorably impacted the Company's effective tax rate by 8.2% for the six months ended March 31, 2019. The Company expects to pay $182.6 million related to the transition tax, which is net of overpayments and tax credits, over a six-year period commencing in January 2021. There were no adjustments recorded to deferred income taxes related to the 2017 Tax Act during the three months ended December 31, 2018. Other Information The Company files income tax returns in U.S. federal and state jurisdictions as well as various foreign jurisdictions. As of March 31, 2019 , the Company had unrecognized tax benefits, defined as the aggregate tax effect of differences between tax return positions and the benefits recognized in the Company’s financial statements, of $109.4 million ( $83.2 million , net of federal benefit). If recognized, $65.0 million of these tax benefits would have reduced income tax expense and the effective tax rate. Included in this amount is $16.5 million of interest and penalties, which the Company records in Income Tax (Benefit) Expense in the Company's Consolidated Statements of Operations. In the six months ended March 31, 2019 , unrecognized tax benefits decreased by $3.5 million . Over the next 12 months, it is reasonably possible that state tax audit resolutions and the expiration of statutes of limitations could result in a reduction of unrecognized tax benefits by approximately $4.5 million . The Company's effective tax rates were (49.5)% and 7.0% for the three and six months ended March 31, 2019 , respectively. The Company's effective tax rates were 21.9% and (58.8)% for the three and six months ended March 31, 2018 , respectively. The effective tax rates in the three and six months ended March 31, 2019 were primarily impacted by the $570.0 million impairment of long-lived assets (see Note 5), which changed the mix of domestic and international income. The effective tax rate in the six months ended March 31, 2019 was also impacted by the $37.0 million decrease to the Company's transition tax related to the 2017 Tax Act. The effective tax rate in the six months ended March 31, 2018 was primarily impacted by the effect of the 2017 Tax Act. The Company's effective tax rates for all periods reported herein were favorably impacted by the Company's international businesses in Switzerland and Ireland, which have lower income tax rates, and the benefit from stock option exercises and restricted stock vesting.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	6 Months Ended
	Mar. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets The following is a summary of the changes in the carrying value of goodwill, by reportable segment, for the six months ended March 31, 2019 : (in thousands) Pharmaceutical Distribution Services Other Total Goodwill as of September 30, 2018 $ 4,852,775 $ 1,811,497 $ 6,664,272 Goodwill recognized in connection with acquisitions — 35,871 35,871 Purchase price accounting adjustments — 591 591 Foreign currency translation — (1,053 ) (1,053 ) Goodwill as of March 31, 2019 $ 4,852,775 $ 1,846,906 $ 6,699,681 The following is a summary of other intangible assets: March 31, 2019 September 30, 2018 (in thousands) Weighted Average Remaining Useful Life Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Indefinite-lived trade names $ 685,306 $ — $ 685,306 $ 685,380 $ — $ 685,380 Finite-lived: Customer relationships 14 years 1,930,986 (431,340 ) 1,499,646 2,549,245 (555,440 ) 1,993,805 Trade names and other 13 years 261,482 (90,437 ) 171,045 397,946 (129,303 ) 268,643 Total other intangible assets $ 2,877,774 $ (521,777 ) $ 2,355,997 $ 3,632,571 $ (684,743 ) $ 2,947,828 Amortization expense for finite-lived intangible assets was $48.5 million and $46.7 million in the three months ended March 31, 2019 and 2018 , respectively. Amortization expense for finite-lived intangible assets was $95.7 million and $86.9 million in the six months ended March 31, 2019 and 2018 , respectively. Amortization expense for finite-lived intangible assets is estimated to be $164.3 million in fiscal 2019 , $132.4 million in fiscal 2020 , $128.5 million in fiscal 2021 , $127.0 million in fiscal 2022 , $125.9 million in fiscal 2023 , and $1,088.3 million thereafter. After U.S. Food and Drug Administration ("FDA") inspections of PharMEDium Healthcare Holdings, Inc.'s ("PharMEDium") compounding facilities, the Company voluntarily suspended production activities in December 2017 at its largest compounding facility located in Memphis, Tennessee pending execution of certain remedial measures. The Company has been in communication with the FDA and the Consumer Protection Branch of the Civil Division of the Department of Justice ("DOJ") regarding its ongoing compliance efforts at PharMEDium and the entry into a consent decree. The entry into a consent decree is expected to apply to the PharMEDium facilities in Memphis, Tennessee; Dayton, New Jersey; and Sugar Land, Texas; and to the PharMEDium headquarters in Lake Forest, Illinois. The Company currently expects that any such consent decree would permit commercial operations to continue at the Sugar Land and Dayton compounding facilities and administrative operations to continue at the Lake Forest headquarters, subject to the successful completion of certain third-party audits, and would specify requirements, including the completion of a third-party audit, that must be satisfied prior to the resumption of commercial operations at the Memphis facility. The Company cannot predict when the negotiations with the FDA and DOJ will be completed, but currently believes it is likely that a consent decree will be entered into during the fiscal quarter ending June 30, 2019. As a result of the continued suspension of production activities at PharMEDium's compounding facility located in Memphis, Tennessee, and further negotiations with the FDA and the DOJ regarding a potential consent decree, the Company updated its recoverability assessment of PharMEDium's long-lived assets as of March 31, 2019 . The recoverability assessment was based upon comparing its forecasted undiscounted cash flows to the carrying value of the PharMEDium asset group. The carrying value of the asset group was $792 million as of March 31, 2019 . The PharMEDium asset group is included in the Pharmaceutical Distribution Services reportable segment. Using forecasted undiscounted cash flows that were based on the weighted average of multiple strategic alternatives, the Company concluded that the carrying value of the PharMEDium long-lived asset group was not recoverable as of March 31, 2019 . The forecasted undiscounted cash flows as of March 31, 2019 were lower than the forecasted undiscounted cash flows as of December 31, 2018 as PharMEDium recently revised its long-range plan, due in part to the status of negotiations with the FDA and the DOJ regarding a potential consent decree. The Company then performed an impairment test by comparing the PharMEDium asset group's fair value of $222 million to its carrying value, which resulted in a $570.0 million impairment loss. Significant assumptions used in estimating the fair value of PharMEDium's asset group included (i) a 15% discount rate, which contemplated a higher risk at PharMEDium; (ii) the estimated costs and length of time necessary to address the FDA compliance matters; (iii) the period in which PharMEDium will resume production at or near capacity; and (iv) the estimated operating margins when considering the likelihood of higher operating and compliance costs. The Company believes that its fair value assumptions were representative of market participant assumptions; however, the forecasted cash flows used to estimate fair value and measure the related impairment are inherently uncertain and include assumptions that could differ from actual results in future periods. This represents a Level 3 nonrecurring fair value measurement. The Company allocated $522.1 million of the impairment to finite-lived intangibles and $47.9 million of the impairment to property and equipment.

Debt

Debt	6 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Debt	Debt Debt consisted of the following: (in thousands) March 31, September 30, Revolving credit note $ — $ — Term loans due in 2020 399,655 398,665 Overdraft facility due 2021 (£30,000) 14,820 13,269 Receivables securitization facility due 2021 500,000 500,000 Multi-currency revolving credit facility due 2023 — — $500,000, 3.50% senior notes due 2021 498,650 498,392 $500,000, 3.40% senior notes due 2024 497,499 497,255 $500,000, 3.25% senior notes due 2025 495,972 495,632 $750,000, 3.45% senior notes due 2027 742,678 742,258 $500,000, 4.25% senior notes due 2045 494,406 494,298 $500,000, 4.30% senior notes due 2047 492,355 492,222 Capital lease obligations 50 745 Nonrecourse debt 156,388 177,453 Total debt 4,292,473 4,310,189 Less AmerisourceBergen Corporation current portion 164,840 13,976 Less nonrecourse current portion 118,133 137,681 Total, net of current portion $ 4,009,500 $ 4,158,532 Multi-Currency Revolving Credit Facility The Company has a $1.4 billion multi-currency senior unsecured revolving credit facility ("Multi-Currency Revolving Credit Facility"), which was scheduled to expire in November 2021 , with a syndicate of lenders. In October 2018, the Company entered into an amendment to, among other things, extend the maturity to October 2023 and modify certain restrictive covenants, including modifications to allow for indebtedness of foreign subsidiaries. Interest on borrowings under the Multi-Currency Revolving Credit Facility accrues at specified rates based on the Company’s debt rating and ranges from 70 basis points to 110 basis points over CDOR/LIBOR/EURIBOR/Bankers Acceptance Stamping Fee, as applicable ( 91 basis points over CDOR/LIBOR/EURIBOR/Bankers Acceptance Stamping Fee as of March 31, 2019 ) and from 0 basis points to 10 basis points over the alternate base rate and Canadian prime rate , as applicable. The Company pays facility fees to maintain the availability under the Multi-Currency Revolving Credit Facility at specified rates based on its debt rating, ranging from 5 basis points to 15 basis points , annually, of the total commitment ( 9 basis points as of March 31, 2019 ). The Company may choose to repay or reduce its commitments under the Multi-Currency Revolving Credit Facility at any time. The Multi-Currency Revolving Credit Facility contains covenants, including compliance with a financial leverage ratio test, as well as others that impose limitations on, among other things, indebtedness of subsidiaries and asset sales, with which the Company was compliant as of March 31, 2019 . Commercial Paper Program The Company has a commercial paper program whereby it may from time to time issue short-term promissory notes in an aggregate amount of up to $1.4 billion at any one time. Amounts available under the program may be borrowed, repaid, and re-borrowed from time to time. The maturities on the notes will vary, but may not exceed 365 days from the date of issuance. The notes will bear interest, if interest bearing, or will be sold at a discount from their face amounts. The commercial paper program does not increase the Company’s borrowing capacity as it is fully backed by the Company’s Multi-Currency Revolving Credit Facility. There were no borrowings outstanding under the commercial paper program as of March 31, 2019 . Receivables Securitization Facility The Company has a $1,450 million receivables securitization facility ("Receivables Securitization Facility"), which was scheduled to expire in November 2019 . In October 2018, the Company entered into an amendment to extend the maturity date to October 2021. The Company has available to it an accordion feature whereby the commitment on the Receivables Securitization Facility may be increased by up to $250 million , subject to lender approval, for seasonal needs during the December and March quarters. Interest rates are based on prevailing market rates for short-term commercial paper or LIBOR, plus a program fee. The Company pays a customary unused fee at prevailing market rates, annually, to maintain the availability under the Receivables Securitization Facility. The Receivables Securitization Facility contains similar covenants to the Multi-Currency Revolving Credit Facility, with which the Company was compliant as of March 31, 2019 . In April 2019, the Company elected to repay $150.0 million , which is classified in "Short-Term Debt" on the Company's March 31, 2019 Consolidated Balance Sheet, of its outstanding Receivables Securitization Facility balance prior to the scheduled maturity date. Revolving Credit Note and Overdraft Facility The Company has an uncommitted, unsecured line of credit available to it pursuant to a revolving credit note ("Revolving Credit Note"). The Revolving Credit Note provides the Company with the ability to request short-term unsecured revolving credit loans from time to time in a principal amount not to exceed $75 million . The Revolving Credit Note may be decreased or terminated by the bank or the Company at any time without prior notice. The Company also has a £30 million uncommitted U.K. overdraft facility ("Overdraft Facility"), which expires in February 2021, to fund short-term normal trading cycle fluctuations related to its MWI business. Term Loans In October 2018, the Company refinanced $400 million of outstanding term loans by issuing a new $400 million variable-rate term loan ("October 2018 Term Loan"), which matures in October 2020. The October 2018 Term Loan bears interest at a rate equal to a base rate or LIBOR, plus a margin of 65 basis points. The October 2018 Term Loan contains similar covenants to the Multi-Currency Revolving Credit Facility, with which the Company was compliant as of March 31, 2019 . Nonrecourse Debt Nonrecourse debt is comprised of short-term and long-term debt belonging to the Brazil subsidiaries and is repaid solely from the Brazil subsidiaries' cash flows and such debt agreements provide that the repayment of the loans (and interest thereon) is secured solely by the capital stock, physical assets, contracts, and cash flows of the Brazil subsidiaries.

Stockholders' Equity and Earnin

Stockholders' Equity and Earnings per Share	6 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Stockholders' Equity and Earnings per Share	Stockholders’ Equity and Earnings per Share In November 2018 , the Company’s board of directors increased the quarterly cash dividend by 5% from $0.38 per share to $0.40 per share. In November 2016, the Company's board of directors authorized a share repurchase program allowing the Company to purchase up to $1.0 billion of its outstanding shares of common stock, subject to market conditions. During the six months ended March 31, 2019 , the Company purchased 1.4 million shares of its common stock for a total of $125.8 million , which excluded $24.0 million of September 2018 purchases that cash settled in October 2018, to complete its authorization under this program. In October 2018, the Company's board of directors authorized a new share repurchase program allowing the Company to purchase up to $1.0 billion of its outstanding shares of common stock, subject to market conditions. During the six months ended March 31, 2019 , the Company purchased 2.6 million shares of its common stock for a total of $198.1 million . As of March 31, 2019 , the Company had $801.9 million of availability remaining under this program. Basic earnings per share is computed by dividing net income attributable to AmerisourceBergen Corporation by the weighted average number of shares of common stock outstanding during the periods presented. Diluted earnings per share is computed by dividing net income attributable to AmerisourceBergen Corporation by the weighted average number of shares of common stock outstanding, plus the dilutive effect of stock options and restricted stock units during the periods presented. The following illustrates the components of diluted weighted average shares outstanding for the periods indicated: Three months ended Six months ended (in thousands) 2019 2018 2019 2018 Weighted average common shares outstanding - basic 210,934 219,200 211,503 218,763 Dilutive effect of stock options and restricted stock units 1,629 3,103 1,772 2,802 Weighted average common shares outstanding - diluted 212,563 222,303 213,275 221,565 The potentially dilutive stock options and restricted stock units that were antidilutive for the three and six months ended March 31, 2019 were 5.4 million and 4.6 million , respectively. The potentially dilutive stock options and restricted stock units that were antidilutive for the three and six months ended March 31, 2018 were 1.9 million and 3.2 million , respectively.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Mar. 31, 2019
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Walgreens Boots Alliance, Inc. ("WBA") owns more than 10% of the Company’s outstanding common stock and is, therefore, considered a related party. The Company operates under various agreements and arrangements with WBA, including a pharmaceutical distribution agreement pursuant to which the Company distributes pharmaceutical products to WBA and an agreement that provides the Company the ability to access favorable economic pricing and generic products through a generic purchasing services arrangement with Walgreens Boots Alliance Development GmbH. Both of these agreements expire in 2026. Revenue from the various agreements and arrangements with WBA was $14.6 billion and $29.9 billion in the three and six months ended March 31, 2019 , respectively. Revenue from the various agreements and arrangements with WBA was $13.4 billion and $26.0 billion in the three and six months ended March 31, 2018 , respectively. The Company’s receivable from WBA, net of incentives, was $5.9 billion and $5.6 billion as of March 31, 2019 and September 30, 2018 , respectively.

Employee Severance, Litigation,

Employee Severance, Litigation, and Other	6 Months Ended
	Mar. 31, 2019
Restructuring and Related Activities [Abstract]
Employee Severance, Litigation, and Other	Employee Severance, Litigation, and Other The following illustrates the charges incurred by the Company relating to Employee Severance, Litigation, and Other for the periods indicated: Three months ended Six months ended (in thousands) 2019 2018 2019 2018 Employee severance $ 14,021 $ 20,778 $ 18,806 $ 28,449 Litigation and opioid-related costs 13,822 7,629 28,361 10,437 Other 27,546 9,042 48,894 28,584 Total employee severance, litigation, and other $ 55,389 $ 37,449 $ 96,061 $ 67,470 Employee severance in the three and six months ended March 31, 2019 included costs primarily related to PharMEDium restructuring activities, position eliminations resulting from our business transformation efforts and the integration of H.D. Smith, and restructuring activities related to our consulting business. Employee severance in the three and six months ended March 31, 2018 included costs primarily related to position eliminations resulting from our business transformation efforts. Litigation and opioid-related costs in the three and six months ended March 31, 2019 and 2018 primarily related to legal fees in connection with opioid lawsuits and investigations. Other costs in the three months ended March 31, 2019 included $11.5 million of acquisition-related deal and integration costs (primarily related to the integration of H.D. Smith), $9.9 million related to the Company's business transformation efforts, and $6.2 million of other restructuring initiatives. Other costs in the six months ended March 31, 2019 included $22.0 million of acquisition-related deal and integration costs (primarily related to the integration of H.D. Smith), $16.9 million related to the Company's business transformation efforts, and $10.0 million of other restructuring initiatives. Other costs in the three months ended March 31, 2018 included $6.0 million related to the Company's business transformation efforts and $3.1 million of other restructuring initiatives. Other costs in the six months ended March 31, 2018 included $12.9 million of acquisition-related deal and integration costs, $10.7 million related to the Company's business transformation efforts, and $5.0 million of other restructuring initiatives.

Legal Matters and Contingencies

Legal Matters and Contingencies	6 Months Ended
	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Legal Matters and Contingencies	Legal Matters and Contingencies In the ordinary course of its business, the Company becomes involved in lawsuits, administrative proceedings, government subpoenas, government investigations, and other disputes, including antitrust, commercial, environmental, product liability, intellectual property, regulatory, employment discrimination, and other matters. Significant damages or penalties may be sought from the Company in some matters, and some matters may require years for the Company to resolve. The Company records a reserve for these matters when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. With respect to the specific legal proceedings and claims described below, unless otherwise noted, the amount or range of possible losses is not reasonably estimable. There can be no assurance that the settlement, resolution, or other outcome of one or more matters, including the matters set forth below, during any subsequent reporting period will not have a material adverse effect on the Company's results of operations or cash flows for that period or on the Company's financial condition. For those matters for which the Company has not recognized a liability, the Company cannot predict the outcome of their impact on the Company as uncertainty remains with regard to whether such matters will proceed to trial, whether settlements will be reached, and the amount and terms of any such settlements. Outcomes may include settlements in significant amounts that are not currently estimable, limitations on the Company's conduct, the imposition of corporate integrity obligations, and/or other civil and criminal penalties. Opioid Lawsuits and Investigations A significant number of counties, municipalities, and other governmental entities in a majority of U.S. states and Puerto Rico, as well as several states and tribes, have filed lawsuits in various federal, state and other courts against pharmaceutical wholesale distributors (including the Company and its subsidiary AmerisourceBergen Drug Corporation ("ABDC")), pharmaceutical manufacturers, retail chains, medical practices, and physicians relating to the distribution of prescription opioid pain medications. Additionally, a significant number of counties and municipalities have also named H.D. Smith, a subsidiary that the Company acquired in January 2018, as a defendant in such lawsuits. Other lawsuits regarding the distribution of prescription opioid pain medications have been filed by: third-party payors and similar entities; hospitals; hospital groups; and individuals, including cases styled as putative class actions. The lawsuits, which have been filed in federal, state, and other courts, generally allege violations of controlled substance laws and various other statutes as well as common law claims, including negligence, public nuisance, and unjust enrichment, and seek equitable relief and monetary damages. An initial group of cases was consolidated for Multidistrict Litigation ("MDL") proceedings before the United States District Court for the Northern District of Ohio (the "Court") in December 2017. Additional cases have been, and will likely continue to be, transferred to the MDL. In April 2018, the Court issued an order creating a litigation track, which includes dispositive motion practice, discovery, and trials in certain bellwether jurisdictions that are scheduled to commence in October 2019. In December 2018, the Court dismissed certain public nuisance claims in the first bellwether cases and allowed the majority of the claims to proceed. On December 31, 2018, the Court issued an order selecting two additional cases for a second bellwether discovery and trial track. The timing of discovery, motion practice, and trials for the second set of bellwether cases has not yet been determined. The Court has continued to oversee court-ordered settlement discussions with attorneys for the plaintiffs and certain states that it instituted at the beginning of the MDL proceedings. Further, in June 2018, the Court granted a motion permitting the United States, through the DOJ, to participate in settlement discussions and as a friend of the Court by providing information to facilitate non-monetary remedies. Aside from those parties that have already filed suit, other entities, including additional attorneys general’s offices, counties, and cities in multiple states, have indicated their intent to sue. The Company is vigorously defending itself in the pending lawsuits and intends to vigorously defend itself against any threatened lawsuits. The Company is not in a position to assess the likely outcome or its exposure, if any, with respect to these matters. In addition, in September 2017, the Company received a request for documents and information on behalf of attorneys general from a coalition of states who are investigating a number of manufacturers and distributors (including ABDC) regarding the distribution of prescription opioid pain medications. The Company is engaged in discussions with the representatives of the attorneys general regarding this request and has been producing responsive documents. The Company has also received subpoenas, civil investigative demands, and other requests for information, requesting the production of documents regarding the distribution of prescription opioid pain medications from government agencies in other jurisdictions, including certain states. The Company is engaged in discussions with representatives from these government agencies regarding the requests and has been producing responsive documents. In July 2017, the U.S. Attorney's Office for the District of New Jersey ("USAO-NJ") and the Drug Enforcement Administration ("DEA") served an administrative subpoena requesting documents relating to ABDC's diversion control programs from 2013 to the present. The Company is responding to the 2017 subpoena and continues to engage in dialogue with the USAO-NJ. Subsequent to the 2017 subpoena, the Company also received administrative subpoenas from the U.S. Attorney's Offices for the Eastern District of New York, the District of Colorado, the Northern District of West Virginia, the Western District of Michigan, the Middle District of Florida, and the Eastern District of California. Those subpoenas are substantively similar to the subpoena received from the USAO-NJ in 2017. The Company has been engaged in discussions with the various U.S. Attorney’s Offices and has been producing documents in response to the subpoenas. Government Enforcement and Related Litigation Matters Various government agencies, including the FDA, the Consumer Protection Branch of the Civil Division of the DOJ, and state boards of pharmacy, regulate the compounding of pharmaceutical products. The Company’s subsidiary, PharMEDium, operates Section 503B outsourcing facilities that must comply with current Good Manufacturing Practice ("cGMP") requirements and are inspected by the FDA periodically to determine compliance. The FDA and the DOJ have broad enforcement powers, including the authority to enjoin PharMEDium's Section 503B outsourcing facilities from distributing pharmaceutical products. The Company continues to be in communication with the FDA and the Consumer Protection Branch of the Civil Division of the DOJ regarding the ongoing compliance efforts of PharMEDium and the entry into a consent decree. A consent decree could result in the disruption or suspension of operations at one or more facilities. Violations of a decree could also result in monetary penalties or further enforcement action. The entry into a consent decree is expected to apply to the PharMEDium facilities in Memphis, Tennessee; Dayton, New Jersey; and Sugar Land, Texas; and to the PharMEDium headquarters in Lake Forest, Illinois. The Company currently expects that any such consent decree would permit commercial operations to continue at the Sugar Land and Dayton compounding facilities and administrative operations to continue at the Lake Forest headquarters, subject to the successful completion of certain third-party audits, and would specify requirements, including the completion of a third-party audit, that must be satisfied prior to the resumption of commercial operations at the Memphis facility. The Company cannot predict when the negotiations with the FDA and DOJ will be completed, but currently believes it is likely that a consent decree will be entered into during the fiscal quarter ending June 30, 2019. Additionally, state boards of pharmacy may revoke, limit, or deny approval of licenses required under state law to compound or distribute pharmaceutical products. As a result of reciprocal state actions initiated due to the FDA’s inspectional observations, PharMEDium has suspended shipping of its compounded sterile preparations into several states, either voluntarily, by consent or pursuant to orders of state licensing authorities. Subpoenas and Ongoing Investigations From time to time, the Company receives subpoenas or requests for information from various government agencies relating to the Company's business or to the business of a customer, supplier, or other industry participant. The Company's responses often require time and effort and can result in considerable costs being incurred. Most of these matters are resolved without incident; however, such subpoenas or requests can lead to the assertion of claims or the commencement of civil or criminal legal proceedings against the Company and other members of the healthcare industry, as well as to substantial settlements. In January 2017, the Company's subsidiary U.S. Bioservices Corporation received a subpoena for information from the U.S. Attorney's Office for the Eastern District of New York ("USAO-EDNY") relating to its activities in connection with billing for products and making returns of potential overpayments to government payers. The Company engaged in discussions with the USAO-EDNY and produced documents in response to the subpoena. In April 2019, the government informed the Company that it had filed a notice with the U.S. District Court for the Eastern District of New York that it was declining to intervene in a filed qui tam action related to its investigation. To date, the case remains under seal and the Company has not received any communication from counsel for relator(s) regarding whether or not relator(s) will pursue the action independently of the government. In November 2017, the Company’s subsidiary PharMEDium received a grand jury subpoena for documents from the U.S. Attorney's Office for the Western District of Tennessee ("USAO-WDTN") seeking various documents, including information generally related to the laboratory testing procedures of PharMEDium's products, and more specifically, for PharMEDium products packaged in a certain type of syringe at its Memphis, Tennessee facility. The Company engaged in discussions with the USAO-WDTN and produced documents in response to the subpoena. Other Contingencies New York State ("NYS") enacted the Opioid Stewardship Act ("OSA"), which went into effect on July 1, 2018. The OSA established an annual $100 million Opioid Stewardship Fund (the "Fund") and requires manufacturers, distributors, and importers licensed in NYS to ratably source the Fund. The ratable share of the assessment for each licensee was to be based upon opioids sold or distributed to or within NYS. In the fourth quarter of the fiscal year ended September 30, 2018, the Company accrued $22 million as an estimate of its liability under the OSA for opioids distributed from January 1, 2017 through September 30, 2018 and recognized this reserve in Cost of Goods Sold on its Consolidated Statement of Operations and in Accrued Expenses and Other on its Consolidated Balance Sheet as of September 30, 2018. In December 2018, the OSA was ruled unconstitutional by the U.S. District Court for the Southern District of New York, and, as a result, the Company reversed the $22.0 million accrual in the quarter ended December 31, 2018. NYS filed an appeal of the court decision on January 17, 2019; however, the Company does not believe a loss contingency is probable. Litigation Settlements Antitrust Settlements Numerous lawsuits have been filed against certain brand pharmaceutical manufacturers alleging that the manufacturer, by itself or in concert with others, took improper actions to delay or prevent generic drugs from entering the market. These lawsuits are generally brought as class actions. The Company is not typically named as a plaintiff in these lawsuits, but has been a member of the direct purchasers' class (i.e., those purchasers who purchase directly from these pharmaceutical manufacturers). None of the lawsuits have gone to trial, but some have settled in the past with the Company receiving proceeds from the settlement funds. During the three and six months ended March 31, 2019 , the Company recognized gains of $52.0 million and $139.3 million , respectively, related to these lawsuits. The Company recognized gains of $0.3 million during the three and six months ended March 31, 2018 related to these lawsuits. These gains, which are net of attorney fees and estimated payments due to other parties, were recorded as reductions to cost of goods sold in the Company’s Consolidated Statements of Operations.

Litigation Settlements

Litigation Settlements	6 Months Ended
	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Litigation Settlements	Legal Matters and Contingencies In the ordinary course of its business, the Company becomes involved in lawsuits, administrative proceedings, government subpoenas, government investigations, and other disputes, including antitrust, commercial, environmental, product liability, intellectual property, regulatory, employment discrimination, and other matters. Significant damages or penalties may be sought from the Company in some matters, and some matters may require years for the Company to resolve. The Company records a reserve for these matters when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. With respect to the specific legal proceedings and claims described below, unless otherwise noted, the amount or range of possible losses is not reasonably estimable. There can be no assurance that the settlement, resolution, or other outcome of one or more matters, including the matters set forth below, during any subsequent reporting period will not have a material adverse effect on the Company's results of operations or cash flows for that period or on the Company's financial condition. For those matters for which the Company has not recognized a liability, the Company cannot predict the outcome of their impact on the Company as uncertainty remains with regard to whether such matters will proceed to trial, whether settlements will be reached, and the amount and terms of any such settlements. Outcomes may include settlements in significant amounts that are not currently estimable, limitations on the Company's conduct, the imposition of corporate integrity obligations, and/or other civil and criminal penalties. Opioid Lawsuits and Investigations A significant number of counties, municipalities, and other governmental entities in a majority of U.S. states and Puerto Rico, as well as several states and tribes, have filed lawsuits in various federal, state and other courts against pharmaceutical wholesale distributors (including the Company and its subsidiary AmerisourceBergen Drug Corporation ("ABDC")), pharmaceutical manufacturers, retail chains, medical practices, and physicians relating to the distribution of prescription opioid pain medications. Additionally, a significant number of counties and municipalities have also named H.D. Smith, a subsidiary that the Company acquired in January 2018, as a defendant in such lawsuits. Other lawsuits regarding the distribution of prescription opioid pain medications have been filed by: third-party payors and similar entities; hospitals; hospital groups; and individuals, including cases styled as putative class actions. The lawsuits, which have been filed in federal, state, and other courts, generally allege violations of controlled substance laws and various other statutes as well as common law claims, including negligence, public nuisance, and unjust enrichment, and seek equitable relief and monetary damages. An initial group of cases was consolidated for Multidistrict Litigation ("MDL") proceedings before the United States District Court for the Northern District of Ohio (the "Court") in December 2017. Additional cases have been, and will likely continue to be, transferred to the MDL. In April 2018, the Court issued an order creating a litigation track, which includes dispositive motion practice, discovery, and trials in certain bellwether jurisdictions that are scheduled to commence in October 2019. In December 2018, the Court dismissed certain public nuisance claims in the first bellwether cases and allowed the majority of the claims to proceed. On December 31, 2018, the Court issued an order selecting two additional cases for a second bellwether discovery and trial track. The timing of discovery, motion practice, and trials for the second set of bellwether cases has not yet been determined. The Court has continued to oversee court-ordered settlement discussions with attorneys for the plaintiffs and certain states that it instituted at the beginning of the MDL proceedings. Further, in June 2018, the Court granted a motion permitting the United States, through the DOJ, to participate in settlement discussions and as a friend of the Court by providing information to facilitate non-monetary remedies. Aside from those parties that have already filed suit, other entities, including additional attorneys general’s offices, counties, and cities in multiple states, have indicated their intent to sue. The Company is vigorously defending itself in the pending lawsuits and intends to vigorously defend itself against any threatened lawsuits. The Company is not in a position to assess the likely outcome or its exposure, if any, with respect to these matters. In addition, in September 2017, the Company received a request for documents and information on behalf of attorneys general from a coalition of states who are investigating a number of manufacturers and distributors (including ABDC) regarding the distribution of prescription opioid pain medications. The Company is engaged in discussions with the representatives of the attorneys general regarding this request and has been producing responsive documents. The Company has also received subpoenas, civil investigative demands, and other requests for information, requesting the production of documents regarding the distribution of prescription opioid pain medications from government agencies in other jurisdictions, including certain states. The Company is engaged in discussions with representatives from these government agencies regarding the requests and has been producing responsive documents. In July 2017, the U.S. Attorney's Office for the District of New Jersey ("USAO-NJ") and the Drug Enforcement Administration ("DEA") served an administrative subpoena requesting documents relating to ABDC's diversion control programs from 2013 to the present. The Company is responding to the 2017 subpoena and continues to engage in dialogue with the USAO-NJ. Subsequent to the 2017 subpoena, the Company also received administrative subpoenas from the U.S. Attorney's Offices for the Eastern District of New York, the District of Colorado, the Northern District of West Virginia, the Western District of Michigan, the Middle District of Florida, and the Eastern District of California. Those subpoenas are substantively similar to the subpoena received from the USAO-NJ in 2017. The Company has been engaged in discussions with the various U.S. Attorney’s Offices and has been producing documents in response to the subpoenas. Government Enforcement and Related Litigation Matters Various government agencies, including the FDA, the Consumer Protection Branch of the Civil Division of the DOJ, and state boards of pharmacy, regulate the compounding of pharmaceutical products. The Company’s subsidiary, PharMEDium, operates Section 503B outsourcing facilities that must comply with current Good Manufacturing Practice ("cGMP") requirements and are inspected by the FDA periodically to determine compliance. The FDA and the DOJ have broad enforcement powers, including the authority to enjoin PharMEDium's Section 503B outsourcing facilities from distributing pharmaceutical products. The Company continues to be in communication with the FDA and the Consumer Protection Branch of the Civil Division of the DOJ regarding the ongoing compliance efforts of PharMEDium and the entry into a consent decree. A consent decree could result in the disruption or suspension of operations at one or more facilities. Violations of a decree could also result in monetary penalties or further enforcement action. The entry into a consent decree is expected to apply to the PharMEDium facilities in Memphis, Tennessee; Dayton, New Jersey; and Sugar Land, Texas; and to the PharMEDium headquarters in Lake Forest, Illinois. The Company currently expects that any such consent decree would permit commercial operations to continue at the Sugar Land and Dayton compounding facilities and administrative operations to continue at the Lake Forest headquarters, subject to the successful completion of certain third-party audits, and would specify requirements, including the completion of a third-party audit, that must be satisfied prior to the resumption of commercial operations at the Memphis facility. The Company cannot predict when the negotiations with the FDA and DOJ will be completed, but currently believes it is likely that a consent decree will be entered into during the fiscal quarter ending June 30, 2019. Additionally, state boards of pharmacy may revoke, limit, or deny approval of licenses required under state law to compound or distribute pharmaceutical products. As a result of reciprocal state actions initiated due to the FDA’s inspectional observations, PharMEDium has suspended shipping of its compounded sterile preparations into several states, either voluntarily, by consent or pursuant to orders of state licensing authorities. Subpoenas and Ongoing Investigations From time to time, the Company receives subpoenas or requests for information from various government agencies relating to the Company's business or to the business of a customer, supplier, or other industry participant. The Company's responses often require time and effort and can result in considerable costs being incurred. Most of these matters are resolved without incident; however, such subpoenas or requests can lead to the assertion of claims or the commencement of civil or criminal legal proceedings against the Company and other members of the healthcare industry, as well as to substantial settlements. In January 2017, the Company's subsidiary U.S. Bioservices Corporation received a subpoena for information from the U.S. Attorney's Office for the Eastern District of New York ("USAO-EDNY") relating to its activities in connection with billing for products and making returns of potential overpayments to government payers. The Company engaged in discussions with the USAO-EDNY and produced documents in response to the subpoena. In April 2019, the government informed the Company that it had filed a notice with the U.S. District Court for the Eastern District of New York that it was declining to intervene in a filed qui tam action related to its investigation. To date, the case remains under seal and the Company has not received any communication from counsel for relator(s) regarding whether or not relator(s) will pursue the action independently of the government. In November 2017, the Company’s subsidiary PharMEDium received a grand jury subpoena for documents from the U.S. Attorney's Office for the Western District of Tennessee ("USAO-WDTN") seeking various documents, including information generally related to the laboratory testing procedures of PharMEDium's products, and more specifically, for PharMEDium products packaged in a certain type of syringe at its Memphis, Tennessee facility. The Company engaged in discussions with the USAO-WDTN and produced documents in response to the subpoena. Other Contingencies New York State ("NYS") enacted the Opioid Stewardship Act ("OSA"), which went into effect on July 1, 2018. The OSA established an annual $100 million Opioid Stewardship Fund (the "Fund") and requires manufacturers, distributors, and importers licensed in NYS to ratably source the Fund. The ratable share of the assessment for each licensee was to be based upon opioids sold or distributed to or within NYS. In the fourth quarter of the fiscal year ended September 30, 2018, the Company accrued $22 million as an estimate of its liability under the OSA for opioids distributed from January 1, 2017 through September 30, 2018 and recognized this reserve in Cost of Goods Sold on its Consolidated Statement of Operations and in Accrued Expenses and Other on its Consolidated Balance Sheet as of September 30, 2018. In December 2018, the OSA was ruled unconstitutional by the U.S. District Court for the Southern District of New York, and, as a result, the Company reversed the $22.0 million accrual in the quarter ended December 31, 2018. NYS filed an appeal of the court decision on January 17, 2019; however, the Company does not believe a loss contingency is probable. Litigation Settlements Antitrust Settlements Numerous lawsuits have been filed against certain brand pharmaceutical manufacturers alleging that the manufacturer, by itself or in concert with others, took improper actions to delay or prevent generic drugs from entering the market. These lawsuits are generally brought as class actions. The Company is not typically named as a plaintiff in these lawsuits, but has been a member of the direct purchasers' class (i.e., those purchasers who purchase directly from these pharmaceutical manufacturers). None of the lawsuits have gone to trial, but some have settled in the past with the Company receiving proceeds from the settlement funds. During the three and six months ended March 31, 2019 , the Company recognized gains of $52.0 million and $139.3 million , respectively, related to these lawsuits. The Company recognized gains of $0.3 million during the three and six months ended March 31, 2018 related to these lawsuits. These gains, which are net of attorney fees and estimated payments due to other parties, were recorded as reductions to cost of goods sold in the Company’s Consolidated Statements of Operations.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	6 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments The recorded amounts of the Company's cash and cash equivalents, accounts receivable, and accounts payable as of March 31, 2019 and September 30, 2018 approximate fair value based upon the relatively short-term nature of these financial instruments. Within Cash and Cash Equivalents, the Company had $1,625.0 million of investments in money market accounts as of March 31, 2019 and had $1,050.0 million of investments in money market accounts as of September 30, 2018 . The fair value of the money market accounts was determined based upon unadjusted quoted prices in active markets for identical assets, otherwise known as Level 1 inputs. The recorded amount of long-term debt (see Note 6 ) and the corresponding fair value as of March 31, 2019 were $4,009.5 million and $3,932.2 million , respectively. The recorded amount of long-term debt and the corresponding fair value as of September 30, 2018 were $4,158.5 million and $4,000.1 million , respectively. The fair value of long-term debt was determined based upon inputs other than quoted prices, otherwise known as Level 2 inputs.

Business Segment Information

Business Segment Information	6 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Business Segment Information	Business Segment Information The Company is organized based upon the products and services it provides to its customers. The Company's operations are comprised of the Pharmaceutical Distribution Services reportable segment and other operating segments that are not significant enough to require separate reportable segment disclosure and, therefore, have been included in Other for the purpose of reportable segment presentation. Other consists of operating segments that focus on global commercialization services and animal health (MWI Animal Health). The operating segments that focus on global commercialization services include AmerisourceBergen Consulting Services and World Courier. The following illustrates reportable and operating segment revenue for the periods indicated: Three months ended Six months ended (in thousands) 2019 2018 2019 2018 Pharmaceutical Distribution Services $ 41,676,164 $ 39,453,353 $ 85,420,545 $ 78,391,051 Other: MWI Animal Health 947,293 933,003 1,901,877 1,891,575 Global Commercialization Services 718,136 661,375 1,434,490 1,247,754 Total Other 1,665,429 1,594,378 3,336,367 3,139,329 Intersegment eliminations (21,991 ) (13,873 ) (44,858 ) (30,190 ) Revenue $ 43,319,602 $ 41,033,858 $ 88,712,054 $ 81,500,190 Intersegment eliminations primarily represent the elimination of certain Pharmaceutical Distribution Services reportable segment sales to MWI. The following illustrates reportable segment operating income for the periods indicated: Three months ended Six months ended (in thousands) 2019 2018 2019 2018 Pharmaceutical Distribution Services $ 517,034 $ 489,106 $ 890,241 $ 877,288 Other 99,879 97,055 198,813 197,330 Intersegment eliminations (249 ) 171 (556 ) (236 ) Total segment operating income $ 616,664 $ 586,332 $ 1,088,498 $ 1,074,382 The following reconciles total segment operating income to income before income taxes for the periods indicated: Three months ended Six months ended (in thousands) 2019 2018 2019 2018 Total segment operating income $ 616,664 $ 586,332 $ 1,088,498 $ 1,074,382 Gain from antitrust litigation settlements 51,976 338 139,255 338 LIFO credit 66,805 — 69,834 — PharMEDium remediation costs (15,897 ) (22,506 ) (36,392 ) (22,506 ) New York State Opioid Stewardship Act — — 22,000 — Acquisition-related intangibles amortization (46,594 ) (45,295 ) (91,746 ) (84,351 ) Employee severance, litigation, and other (55,389 ) (37,449 ) (96,061 ) (67,470 ) Impairment of long-lived assets (570,000 ) — (570,000 ) — Operating income 47,565 481,420 525,388 900,393 Other (income) loss (14,494 ) 29,123 (11,397 ) 29,447 Interest expense, net 43,275 48,637 85,445 84,501 Loss on consolidation of equity investments — 42,328 — 42,328 Loss on early retirement of debt — — — 23,766 Income before income taxes $ 18,784 $ 361,332 $ 451,340 $ 720,351 Segment operating income is evaluated by the chief operating decision maker ("CODM") of the Company before gain from antitrust litigation settlements; LIFO credit; PharMEDium remediation costs; New York State Opioid Stewardship Act; acquisition-related intangibles amortization; employee severance, litigation, and other; impairment of long-lived assets; other (income) loss; interest expense, net; loss on consolidation of equity investments; and loss on early retirement of debt. Segment measures were adjusted in fiscal 2019 to exclude impairment of long-lived assets as the CODM excludes all such charges in the measurement of segment performance. All corporate office expenses are allocated to the reportable segment level. The Company incurred remediation costs in connection with the suspended production activities at PharMEDium (see Note 5). These remediation costs are primarily classified in Cost of Goods sold in the Consolidated Statements of Operations. Future remediation costs will also include costs related to remediation activities responsive to FDA inspectional observations generally applicable to all of PharMEDium’s 503B outsourcing facilities, including product stability studies. The Company recorded a $13.7 million gain on the sale of an equity investment in Other (Income) Loss in the Company's Consolidated Statements of Operations in the three and six months ended March 31, 2019. The Company recorded a $30.0 million impairment of a non-customer note receivable related to a start-up venture in Other (Income) Loss in the Company's Consolidated Statements of Operations in the three and six months ended March 31, 2018.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial statements present the consolidated financial position, results of operations, and cash flows of AmerisourceBergen Corporation and its subsidiaries, including less than wholly-owned subsidiaries in which AmerisourceBergen Corporation has a controlling financial interest (the "Company"), as of the dates and for the periods indicated. All intercompany accounts and transactions have been eliminated in consolidation. The accompanying unaudited consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles ("GAAP") for interim financial information, the instructions to Form 10-Q, and Rule 10-01 of Regulation S-X. In the opinion of management, all adjustments (consisting only of normal recurring accruals, except as otherwise disclosed herein) considered necessary to present fairly the financial position as of March 31, 2019 and the results of operations and cash flows for the interim periods ended March 31, 2019 and 2018 have been included. Certain information and footnote disclosures normally included in financial statements presented in accordance with U.S. GAAP, but which are not required for interim reporting purposes, have been omitted. The accompanying unaudited consolidated financial statements should be read in conjunction with the financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended September 30, 2018 .
Use of Estimates	The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect amounts reported in the financial statements and accompanying notes. Actual amounts could differ from these estimated amounts.
Recently Adopted Accounting Pronouncements and Recently Issued Accounting Pronouncements Not Yet Adopted	Recently Adopted Accounting Pronouncements In May 2014, the Financial Accounting Standards Board ("FASB") issued ASU No. 2014-09, "Revenue from Contracts with Customers (Topic 606)" ("ASU 2014-09"). ASU 2014-09 supersedes the revenue recognition requirements in Accounting Standards Codification ("ASC") 605 - "Revenue Recognition" and most industry-specific guidance throughout the Codification. ASU 2014-09 outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers. The standard's core principle is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 was originally scheduled to be effective for annual reporting periods beginning after December 15, 2016, including interim periods within those reporting periods. In July 2015, the FASB deferred the effective date of ASU 2014-09 by one year. In March 2016, the FASB issued ASU No. 2016-08, "Revenue from Contracts with Customers (Topic 606) - Principal versus Agent Considerations" ("ASU 2016-08"), which clarifies the implementation guidance for principal versus agent considerations in ASU 2014-09. In April 2016, the FASB issued ASU No. 2016-10, "Revenue from Contracts with Customers (Topic 606) - Identifying Performance Obligations and Licensing" ("ASU 2016-10"), which amends the guidance in ASU 2014-09 related to identifying performance obligations and accounting for licenses of intellectual property. The Company must adopt ASU 2016-08 and ASU 2016-10 with ASU 2014-09, collectively ASC 606. The Company adopted ASC 606 as of October 1, 2018 on a modified retrospective basis for all open contracts as of October 1, 2018. The adoption had an immaterial impact on the Company’s October 1, 2018 retained earnings and will not have a material impact on the Company's revenues, results of operations, or cash flows. The Company did not record any material contract assets, contract liabilities, or deferred contract costs in its Consolidated Balance Sheet upon adoption. The Company's revenues are primarily generated from the distribution of pharmaceutical products. The Company also generates revenues from global commercialization services, which include clinical trial support, post-approval and commercialization support, and global specialty transportation and logistics for the biopharmaceutical industry. See Note 13 for the Company's disaggregated revenue. The Company recognizes revenue related to the distribution of products at a point in time when title and control transfers to customers and there is no further obligation to provide services related to such products. Service revenue is recognized over the period that services are provided to the customer. The Company is generally the principal in a transaction; therefore, revenue is primarily recorded on a gross basis. When the Company is the principal in a transaction, it has determined that it controls the ability to direct the use of the product or service prior to the transfer to a customer, it is primarily responsible for fulfilling the promise to provide the product or service to its customer, it has discretion in establishing pricing, and it controls the relationship with the customer. Revenue is recognized at the amount of consideration expected to be received, which is generally based on a purchase order, and is net of estimated sales returns and allowances, other customer incentives, and sales tax. The Company’s customer sales return policy generally allows customers to return products only if the products can be resold at full value or returned to suppliers for full credit. The Company records an accrual for estimated customer sales returns at the time of sale to the customer based upon historical return trends. As of March 31, 2019 and September 30, 2018, the Company’s accrual for estimated customer sales returns was $977.9 million and $988.8 million , respectively. In fiscal 2019, due to the adoption of ASC 606, the Company records an asset for the right to recover products from its customers in Right to Recover Asset on its Consolidated Balance Sheet. The Company's asset for the right to recover products from its customers was in Inventories on its Consolidated Balance Sheet as of September 30, 2018 and for all prior periods. The Company elected the practical expedient to expense costs to obtain a contract when incurred when the amortization period would have been one year or less. Additionally, the Company elected the practical expedients to not disclose the value of unsatisfied performance obligations for (i) contracts with an original expected length of one year or less, (ii) contracts for which the Company recognizes revenue at the amount to which it has the right to invoice for services performed, and (iii) for contracts for which the variable consideration is allocated entirely to a wholly unsatisfied performance obligation or to a wholly unsatisfied promise to transfer a distinct good or service that forms part of a single performance obligation. Recently Issued Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02, "Leases (Topic 842)" ("ASU 2016-02"). ASU 2016-02 aims to increase transparency and comparability across organizations by requiring lease assets and lease liabilities to be recognized on the balance sheet as well as key information to be disclosed regarding lease arrangements. ASU 2016-02 is effective for annual reporting periods beginning after December 15, 2018 and interim periods within those fiscal years. Entities are permitted to adopt the standard early, and a modified retrospective application is required. The Company anticipates that the adoption of this new accounting standard will have a material impact on the Company's Consolidated Balance Sheets. However, the Company continues to evaluate the impact of adopting this new accounting standard, and, therefore, cannot reasonably estimate the impact on the results of operations or cash flows at this time. The Company has begun the process of implementing the adoption of this standard, including the implementation of new lease accounting software, policies, processes, and controls. The Company will adopt this standard in the first quarter of fiscal 2020. As of March 31, 2019 , there were no other recently-issued accounting standards that may have a material impact on the Company’s financial position, results of operations, or cash flows upon their adoption.

Variable Interest Entity (Table

Variable Interest Entity (Tables)	6 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of VIE's Assets and Liabilities	The following assets and liabilities of Profarma are included in the Company's Consolidated Balance Sheets: (in thousands) March 31, September 30, Cash and cash equivalents $ 16,711 $ 26,801 Accounts receivables, net 149,223 144,646 Inventories 170,963 168,931 Prepaid expenses and other 59,757 61,924 Property and equipment, net 32,824 32,667 Goodwill 82,309 82,309 Other intangible assets 78,219 80,974 Other long-term assets 8,214 8,912 Total assets $ 598,220 $ 607,164 Accounts payable $ 156,666 $ 150,102 Accrued expenses and other 49,847 37,195 Short-term debt 118,133 115,461 Long-term debt 38,182 39,704 Deferred income taxes 43,233 46,137 Other long-term liabilities 6,539 31,988 Total liabilities $ 412,600 $ 420,587

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	6 Months Ended
	Mar. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of changes in the carrying value of goodwill by reportable segment	The following is a summary of the changes in the carrying value of goodwill, by reportable segment, for the six months ended March 31, 2019 : (in thousands) Pharmaceutical Distribution Services Other Total Goodwill as of September 30, 2018 $ 4,852,775 $ 1,811,497 $ 6,664,272 Goodwill recognized in connection with acquisitions — 35,871 35,871 Purchase price accounting adjustments — 591 591 Foreign currency translation — (1,053 ) (1,053 ) Goodwill as of March 31, 2019 $ 4,852,775 $ 1,846,906 $ 6,699,681
Schedule of indefinite-lived intangible assets	The following is a summary of other intangible assets: March 31, 2019 September 30, 2018 (in thousands) Weighted Average Remaining Useful Life Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Indefinite-lived trade names $ 685,306 $ — $ 685,306 $ 685,380 $ — $ 685,380 Finite-lived: Customer relationships 14 years 1,930,986 (431,340 ) 1,499,646 2,549,245 (555,440 ) 1,993,805 Trade names and other 13 years 261,482 (90,437 ) 171,045 397,946 (129,303 ) 268,643 Total other intangible assets $ 2,877,774 $ (521,777 ) $ 2,355,997 $ 3,632,571 $ (684,743 ) $ 2,947,828
Schedule of finite-lived intangible assets	The following is a summary of other intangible assets: March 31, 2019 September 30, 2018 (in thousands) Weighted Average Remaining Useful Life Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Indefinite-lived trade names $ 685,306 $ — $ 685,306 $ 685,380 $ — $ 685,380 Finite-lived: Customer relationships 14 years 1,930,986 (431,340 ) 1,499,646 2,549,245 (555,440 ) 1,993,805 Trade names and other 13 years 261,482 (90,437 ) 171,045 397,946 (129,303 ) 268,643 Total other intangible assets $ 2,877,774 $ (521,777 ) $ 2,355,997 $ 3,632,571 $ (684,743 ) $ 2,947,828

Debt (Tables)

Debt (Tables)	6 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Schedule of debt instruments	Debt consisted of the following: (in thousands) March 31, September 30, Revolving credit note $ — $ — Term loans due in 2020 399,655 398,665 Overdraft facility due 2021 (£30,000) 14,820 13,269 Receivables securitization facility due 2021 500,000 500,000 Multi-currency revolving credit facility due 2023 — — $500,000, 3.50% senior notes due 2021 498,650 498,392 $500,000, 3.40% senior notes due 2024 497,499 497,255 $500,000, 3.25% senior notes due 2025 495,972 495,632 $750,000, 3.45% senior notes due 2027 742,678 742,258 $500,000, 4.25% senior notes due 2045 494,406 494,298 $500,000, 4.30% senior notes due 2047 492,355 492,222 Capital lease obligations 50 745 Nonrecourse debt 156,388 177,453 Total debt 4,292,473 4,310,189 Less AmerisourceBergen Corporation current portion 164,840 13,976 Less nonrecourse current portion 118,133 137,681 Total, net of current portion $ 4,009,500 $ 4,158,532

Stockholders' Equity and Earn_2

Stockholders' Equity and Earnings per Share (Tables)	6 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Schedule of weighted average number of common shares outstanding	The following illustrates the components of diluted weighted average shares outstanding for the periods indicated: Three months ended Six months ended (in thousands) 2019 2018 2019 2018 Weighted average common shares outstanding - basic 210,934 219,200 211,503 218,763 Dilutive effect of stock options and restricted stock units 1,629 3,103 1,772 2,802 Weighted average common shares outstanding - diluted 212,563 222,303 213,275 221,565

Employee Severance, Litigatio_2

Employee Severance, Litigation, and Other (Tables)	6 Months Ended
	Mar. 31, 2019
Restructuring and Related Activities [Abstract]
Employee severance, litigation, and other charge	The following illustrates the charges incurred by the Company relating to Employee Severance, Litigation, and Other for the periods indicated: Three months ended Six months ended (in thousands) 2019 2018 2019 2018 Employee severance $ 14,021 $ 20,778 $ 18,806 $ 28,449 Litigation and opioid-related costs 13,822 7,629 28,361 10,437 Other 27,546 9,042 48,894 28,584 Total employee severance, litigation, and other $ 55,389 $ 37,449 $ 96,061 $ 67,470

Business Segment Information (T

Business Segment Information (Tables)	6 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Segment revenue	The following illustrates reportable and operating segment revenue for the periods indicated: Three months ended Six months ended (in thousands) 2019 2018 2019 2018 Pharmaceutical Distribution Services $ 41,676,164 $ 39,453,353 $ 85,420,545 $ 78,391,051 Other: MWI Animal Health 947,293 933,003 1,901,877 1,891,575 Global Commercialization Services 718,136 661,375 1,434,490 1,247,754 Total Other 1,665,429 1,594,378 3,336,367 3,139,329 Intersegment eliminations (21,991 ) (13,873 ) (44,858 ) (30,190 ) Revenue $ 43,319,602 $ 41,033,858 $ 88,712,054 $ 81,500,190
Segment operating income	The following illustrates reportable segment operating income for the periods indicated: Three months ended Six months ended (in thousands) 2019 2018 2019 2018 Pharmaceutical Distribution Services $ 517,034 $ 489,106 $ 890,241 $ 877,288 Other 99,879 97,055 198,813 197,330 Intersegment eliminations (249 ) 171 (556 ) (236 ) Total segment operating income $ 616,664 $ 586,332 $ 1,088,498 $ 1,074,382
Reconciliation of total segment operating income to income (loss) from operations before income taxes	The following reconciles total segment operating income to income before income taxes for the periods indicated: Three months ended Six months ended (in thousands) 2019 2018 2019 2018 Total segment operating income $ 616,664 $ 586,332 $ 1,088,498 $ 1,074,382 Gain from antitrust litigation settlements 51,976 338 139,255 338 LIFO credit 66,805 — 69,834 — PharMEDium remediation costs (15,897 ) (22,506 ) (36,392 ) (22,506 ) New York State Opioid Stewardship Act — — 22,000 — Acquisition-related intangibles amortization (46,594 ) (45,295 ) (91,746 ) (84,351 ) Employee severance, litigation, and other (55,389 ) (37,449 ) (96,061 ) (67,470 ) Impairment of long-lived assets (570,000 ) — (570,000 ) — Operating income 47,565 481,420 525,388 900,393 Other (income) loss (14,494 ) 29,123 (11,397 ) 29,447 Interest expense, net 43,275 48,637 85,445 84,501 Loss on consolidation of equity investments — 42,328 — 42,328 Loss on early retirement of debt — — — 23,766 Income before income taxes $ 18,784 $ 361,332 $ 451,340 $ 720,351

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	Mar. 31, 2019	Sep. 30, 2018
Accounting Policies [Abstract]
Accrual for estimated customer sales returns	$ 977.9	$ 988.8

Acquisitions and Investments -

Acquisitions and Investments - NEVSCO (Details) - USD ($) $ in Thousands	1 Months Ended
	Dec. 31, 2017	Mar. 31, 2019	Sep. 30, 2018	Mar. 31, 2018
Business Acquisition [Line Items]
Goodwill		$ 6,699,681	$ 6,664,272
NEVSCO
Business Acquisition [Line Items]
Purchase price in cash	$ 70,000
Goodwill				$ 30,400
Estimated fair value of accounts receivable				8,500
Estimated fair value of inventory				6,700
Estimated fair value of accounts payable				2,900
Estimated fair value of intangible assets acquired				$ 29,800
Customer relationships | NEVSCO
Business Acquisition [Line Items]
Weighted average useful life of intangible asset (in years)	15 years

Acquisitions and Investments _2

Acquisitions and Investments - H.D. Smith (Details) - USD ($) $ in Thousands	1 Months Ended
	Jan. 31, 2018	Mar. 31, 2019	Sep. 30, 2018
Business Acquisition [Line Items]
Goodwill		$ 6,699,681	$ 6,664,272
H.D. Smith
Business Acquisition [Line Items]
Purchase price in cash	$ 815,000
Goodwill	499,900
Estimated fair value of accounts receivable	163,100
Estimated fair value of inventory	350,700
Estimated fair value of accounts payable	366,100
Estimated fair value of intangible assets acquired	167,800
Deferred tax liability	60,600
Customer relationships | H.D. Smith
Business Acquisition [Line Items]
Estimated fair value of intangible assets acquired	$ 156,600
Weighted average useful life of intangible asset (in years)	12 years
Tradename | H.D. Smith
Business Acquisition [Line Items]
Estimated fair value of intangible assets acquired	$ 11,200
Weighted average useful life of intangible asset (in years)	2 years

Acquisitions and Investments _3

Acquisitions and Investments - Profarma and Specialty Joint Ventures (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended
	Sep. 30, 2018	Jan. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Business Acquisition [Line Items]
Goodwill	$ 6,664,272		$ 6,699,681		$ 6,699,681
Loss on consolidation of equity investments			0	$ 42,328	0	$ 42,328
Accumulated Other Comprehensive Loss			$ 0	$ 45,941	$ 0	$ 45,941
Specialty Joint Venture
Business Acquisition [Line Items]
Investment in specialty joint venture	$ 23,600	$ 15,600
Ownership interest in specialty joint venture	89.90%			64.50%		64.50%
Goodwill		3,500
Estimated fair value of accounts receivable		65,000
Estimated fair value of inventory		29,100
Estimated fair value of accounts payable		54,300
Assumed short-term debt		32,700
Assumed cash		28,900
Estimated fair value of intangible assets acquired		$ 4,600
Weighted average useful life of intangible asset (in years)					15 years
Loss on consolidation of equity investments						$ 8,800
Gain on remeasurement of Profarma's previously held equity interest						$ 12,400
Specialty Joint Venture | Customer relationships
Business Acquisition [Line Items]
Weighted average useful life of intangible asset (in years)		15 years
Specialty Joint Venture | Tradename
Business Acquisition [Line Items]
Weighted average useful life of intangible asset (in years)		15 years
Profarma
Business Acquisition [Line Items]
Investment in Profarma		$ 62,500
Ownership interest in Profarma				38.20%		38.20%
Goodwill		142,000
Estimated fair value of accounts receivable		160,100
Estimated fair value of inventory		190,500
Estimated fair value of accounts payable		167,700
Assumed short-term debt		209,900
Assumed long-term debt		12,400
Assumed cash		150,800
Noncontrolling interest		168,000
Estimated fair value of intangible assets acquired		84,600
Deferred tax liability		50,100
Profarma | Customer relationships
Business Acquisition [Line Items]
Estimated fair value of intangible assets acquired		25,900
Profarma | Tradename
Business Acquisition [Line Items]
Estimated fair value of intangible assets acquired		$ 58,700
Minimum | Profarma | Tradename
Business Acquisition [Line Items]
Weighted average useful life of intangible asset (in years)		15 years
Maximum | Profarma | Tradename
Business Acquisition [Line Items]
Weighted average useful life of intangible asset (in years)		25 years
Accumulated Foreign Currency Adjustment Attributable to Parent
Business Acquisition [Line Items]
Accumulated Other Comprehensive Loss						$ 45,900
Level 2 inputs | Specialty Joint Venture
Business Acquisition [Line Items]
Fair value of equity interests				$ 31,200		31,200
Level 2 inputs | Profarma
Business Acquisition [Line Items]
Fair value of equity interests				$ 103,100		$ 103,100

Variable Interest Entity - Fina

Variable Interest Entity - Financial Position of Variable Interest Entity (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2017
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 2,875,750	$ 2,492,516	$ 2,091,359	$ 2,435,115
Inventories	11,373,730	11,918,508
Property and equipment, net	1,858,867	1,892,424
Goodwill	6,699,681	6,664,272
Other long-term assets	273,582	270,942
TOTAL ASSETS	38,810,310	37,669,838
Long-term debt	156,388	177,453
Deferred income taxes	1,857,201	1,829,410
Other long-term liabilities	69,317	110,352
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Cash and cash equivalents	16,711	26,801
Accounts receivables, net	149,223	144,646
Inventories	170,963	168,931
Prepaid expenses and other	59,757	61,924
Property and equipment, net	32,824	32,667
Goodwill	82,309	82,309
Other intangible assets	78,219	80,974
Other long-term assets	8,214	8,912
TOTAL ASSETS	598,220	607,164
Accounts payable	156,666	150,102
Accrued expenses and other	49,847	37,195
Short-term debt	118,133	115,461
Long-term debt	38,182	39,704
Deferred income taxes	43,233	46,137
Other long-term liabilities	6,539	31,988
Total liabilities	$ 412,600	$ 420,587

Income Taxes (Details)

Income Taxes (Details)	3 Months Ended		6 Months Ended
	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)
Income Tax Disclosure [Abstract]
Income tax benefits related to decrease in provisional tax	$ 37,000,000
Effective tax rate adjustment (as a percentage)	0.082
Expected payment related to the transition tax			$ 182,600,000
Adjustments recored to deferred income taxes related to 2017 Tax Act			0
Unrecognized tax benefits	$ 109,400,000		109,400,000
Unrecognized tax benefits, net of federal benefit	83,200,000		83,200,000
Tax benefits that would reduce income tax expense and effective tax rate	65,000,000		65,000,000
Unrecognized tax benefits - interest and penalties	16,500,000		16,500,000
Unrecognized tax benefits - increase (decrease)			(3,500,000)
Significant change in unrecognized tax benefits is reasonably possible	$ 4,500,000		$ 4,500,000
Effective tax rate (as a percentage)	(49.50%)	21.90%	7.00%	(58.80%)
Impairment of long-lived assets	$ 570,000,000	$ 0	$ 570,000,000	$ 0

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets - Schedule of Change in the Carrying Value of Goodwill by Reportable Segment (Details) $ in Thousands	6 Months Ended
	Mar. 31, 2019USD ($)
Goodwill [Roll Forward]
Goodwill	$ 6,664,272
Goodwill recognized in connection with acquisitions	35,871
Purchase price accounting adjustments	591
Foreign currency translation	(1,053)
Goodwill	6,699,681
Operating segments | Pharmaceutical Distribution Services
Goodwill [Roll Forward]
Goodwill	4,852,775
Goodwill recognized in connection with acquisitions	0
Purchase price accounting adjustments	0
Foreign currency translation	0
Goodwill	4,852,775
Operating segments | Other:
Goodwill [Roll Forward]
Goodwill	1,811,497
Goodwill recognized in connection with acquisitions	35,871
Purchase price accounting adjustments	591
Foreign currency translation	(1,053)
Goodwill	$ 1,846,906

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Schedule of Other Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Sep. 30, 2018
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangibles, Accumulated Amortization	$ (521,777)	$ (684,743)
Intangible Assets
Gross Carrying Amount	2,877,774	3,632,571
Net Carrying Amount	2,355,997	2,947,828
Trade names
Indefinite-lived intangibles
Indefinite-lived intangibles	$ 685,306	685,380
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in years)	14 years
Finite-lived intangibles, Gross Carrying Amount	$ 1,930,986	2,549,245
Finite-lived intangibles, Accumulated Amortization	(431,340)	(555,440)
Finite-lived intangibles, Net Carrying Amount	$ 1,499,646	1,993,805
Trade names and other
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in years)	13 years
Finite-lived intangibles, Gross Carrying Amount	$ 261,482	397,946
Finite-lived intangibles, Accumulated Amortization	(90,437)	(129,303)
Finite-lived intangibles, Net Carrying Amount	$ 171,045	$ 268,643

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Business Acquisition [Line Items]
Amortization expense	$ 48,500	$ 46,700	$ 95,700	$ 86,900
Amortization expense, fiscal year maturity
2019	164,300		164,300
2020	132,400		132,400
2021	128,500		128,500
2022	127,000		127,000
2023	125,900		125,900
Thereafter	1,088,300		1,088,300
Impairment of long-lived assets	570,000	$ 0	570,000	$ 0
Pharmedium Healthcare Holdings Inc [Member]
Amortization expense, fiscal year maturity
Carrying value of asset group, excluding goodwill	792,000		792,000
Fair value of asset group	$ 222,000		$ 222,000
Discount rate (as a percentage)	15.00%		15.00%
Finite-lived intangibles
Amortization expense, fiscal year maturity
Impairment of long-lived assets			$ 522,100
Property and equipment
Amortization expense, fiscal year maturity
Impairment of long-lived assets			$ 47,900

Debt - Schedule of Debt Instrum

Debt - Schedule of Debt Instruments (Details)	Mar. 31, 2019GBP (£)	Mar. 31, 2019USD ($)	Sep. 30, 2018USD ($)
Debt Instrument [Line Items]
Long-term debt		$ 156,388,000	$ 177,453,000
Capital lease obligations		50,000	745,000
Total debt		4,292,473,000	4,310,189,000
Less AmerisourceBergen Corporation current portion		164,840,000	13,976,000
Total, net of current portion		4,009,500,000	4,158,532,000
Revolving credit note
Debt Instrument [Line Items]
Maximum borrowing capacity		75,000,000
Long-term debt		0	0
Term loans due in 2020
Debt Instrument [Line Items]
Long-term debt		399,655,000	398,665,000
Overdraft facility due 2021 (£30,000)
Debt Instrument [Line Items]
Maximum borrowing capacity | £	£ 30,000,000
Long-term debt		14,820,000	13,269,000
Receivables securitization facility due 2021
Debt Instrument [Line Items]
Maximum borrowing capacity		1,450,000,000
Long-term debt		500,000,000	500,000,000
Multi-currency revolving credit facility due 2023
Debt Instrument [Line Items]
Maximum borrowing capacity		1,400,000,000
Long-term debt		0	0
$500,000, 3.50% senior notes due 2021
Debt Instrument [Line Items]
Principal amount		$ 500,000,000
Interest rate	3.50%	3.50%
Long-term debt		$ 498,650,000	498,392,000
$500,000, 3.40% senior notes due 2024
Debt Instrument [Line Items]
Principal amount		$ 500,000,000
Interest rate	3.40%	3.40%
Long-term debt		$ 497,499,000	497,255,000
$500,000, 3.25% senior notes due 2025
Debt Instrument [Line Items]
Principal amount		$ 500,000,000
Interest rate	3.25%	3.25%
Long-term debt		$ 495,972,000	495,632,000
$750,000, 3.45% senior notes due 2027
Debt Instrument [Line Items]
Principal amount		$ 750,000,000
Interest rate	3.45%	3.45%
Long-term debt		$ 742,678,000	742,258,000
$500,000, 4.25% senior notes due 2045
Debt Instrument [Line Items]
Principal amount		$ 500,000,000
Interest rate	4.25%	4.25%
Long-term debt		$ 494,406,000	494,298,000
$500,000, 4.30% senior notes due 2047
Debt Instrument [Line Items]
Principal amount		$ 500,000,000
Interest rate	4.30%	4.30%
Long-term debt		$ 492,355,000	492,222,000
Nonrecourse debt
Debt Instrument [Line Items]
Less AmerisourceBergen Corporation current portion		$ 118,133,000	$ 137,681,000

Debt - Additional information (

Debt - Additional information (Details)	Mar. 31, 2019GBP (£)	Apr. 30, 2019USD ($)	Mar. 31, 2019GBP (£)	Mar. 31, 2019USD ($)	Oct. 31, 2018USD ($)	Sep. 30, 2018USD ($)
Debt Instrument [Line Items]
Long-term debt				$ 156,388,000		$ 177,453,000
$750,000, 3.45% senior notes due 2027
Debt Instrument [Line Items]
Interest rate	3.45%		3.45%	3.45%
Long-term debt				$ 742,678,000		742,258,000
Proceeds from issuance of variable-rate term loan				$ 750,000,000
$500,000, 4.30% senior notes due 2047
Debt Instrument [Line Items]
Interest rate	4.30%		4.30%	4.30%
Long-term debt				$ 492,355,000		492,222,000
Proceeds from issuance of variable-rate term loan				500,000,000
Multi-currency revolving credit facility due 2023
Debt Instrument [Line Items]
Maximum borrowing capacity				1,400,000,000
Facility fee	0.09%
Long-term debt				0		0
Multi-currency revolving credit facility due 2023 | Minimum
Debt Instrument [Line Items]
Facility fee			0.05%
Multi-currency revolving credit facility due 2023 | Maximum
Debt Instrument [Line Items]
Facility fee			0.15%
Multi-currency revolving credit facility due 2023 | CDOR / LIBOR / EURIBOR / Bankers Acceptance Stamping Fee
Debt Instrument [Line Items]
Variable rate spread	0.91%
Multi-currency revolving credit facility due 2023 | CDOR / LIBOR / EURIBOR / Bankers Acceptance Stamping Fee | Minimum
Debt Instrument [Line Items]
Variable rate spread			0.70%
Multi-currency revolving credit facility due 2023 | CDOR / LIBOR / EURIBOR / Bankers Acceptance Stamping Fee | Maximum
Debt Instrument [Line Items]
Variable rate spread			1.10%
Multi-currency revolving credit facility due 2023 | Alternate base rate and Canadian prime rate | Minimum
Debt Instrument [Line Items]
Variable rate spread			0.00%
Multi-currency revolving credit facility due 2023 | Alternate base rate and Canadian prime rate | Maximum
Debt Instrument [Line Items]
Variable rate spread			0.10%
Commercial paper
Debt Instrument [Line Items]
Maximum borrowing capacity				1,400,000,000
Debt instrument, term (days)			365 days
Amount outstanding				0
Receivables securitization facility due 2021
Debt Instrument [Line Items]
Maximum borrowing capacity				1,450,000,000
Potential increase in receivables securitization facility				250,000,000
Long-term debt				500,000,000		500,000,000
Revolving credit note
Debt Instrument [Line Items]
Maximum borrowing capacity				75,000,000
Long-term debt				0		0
Overdraft facility due 2021 (£30,000)
Debt Instrument [Line Items]
Maximum borrowing capacity | £	£ 30,000,000		£ 30,000,000
Long-term debt				$ 14,820,000		$ 13,269,000
Refinanced Term Loans
Debt Instrument [Line Items]
Long-term debt					$ 400,000,000
October 2018 Term Loan
Debt Instrument [Line Items]
Proceeds from issuance of variable-rate term loan					$ 400,000,000
October 2018 Term Loan | LIBOR
Debt Instrument [Line Items]
Variable rate spread	0.65%
October 2018 Term Loan | Base rate
Debt Instrument [Line Items]
Variable rate spread	0.65%
Subsequent Event | Receivables securitization facility due 2021
Debt Instrument [Line Items]
Repayments of short-term debt		$ 150,000,000

Stockholders' Equity and Earn_3

Stockholders' Equity and Earnings per Share - Additional Information (Details) - USD ($) $ / shares in Units, shares in Millions	1 Months Ended		3 Months Ended		6 Months Ended
	Oct. 31, 2018	Nov. 30, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Nov. 30, 2016
Equity, Class of Treasury Stock [Line Items]
Percentage increase of cash dividend		5.00%
Cash dividends declared per share of common stock (usd per share)			$ 0.4	$ 0.38	$ 0.8	$ 0.76
Repurchase of common stock			$ 98,124,000	$ 37,712,000	$ 323,974,000	$ 60,208,000
Antidilutive securities excluded from earnings per share computation (shares)			5.4	1.9	4.6	3.2
November 2016 Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Authorized amount under share repurchase program							$ 1,000,000,000
Repurchase of common stock (shares)					1.4
Repurchase of common stock					$ 125,800,000
Cash settled purchases	$ 24,000,000
October 2018 Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Authorized amount under share repurchase program	$ 1,000,000,000
Repurchase of common stock (shares)					2.6
Repurchase of common stock					$ 198,100,000
Availability remaining under program			$ 801,900,000		$ 801,900,000

Stockholders' Equity and Earn_4

Stockholders' Equity and Earnings per Share - Weighted Average Number of Common Shares Outstanding (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Equity [Abstract]
Weighted average common shares outstanding - basic (shares)	210,934	219,200	211,503	218,763
Dilutive effect of stock options, restricted stock, and restricted stock units (shares)	1,629	3,103	1,772	2,802
Weighted average common shares outstanding - diluted (shares)	212,563	222,303	213,275	221,565

Related Party Transactions (Det

Related Party Transactions (Details) - Walgreens Boots Alliance, Inc. - Investor - USD ($) $ in Billions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2018
Related Party Transaction [Line Items]
Revenue from related party	$ 14.6	$ 13.4	$ 29.9	$ 26
Receivable from related party	$ 5.9		$ 5.9		$ 5.6
AmerisourceBergen
Related Party Transaction [Line Items]
Ownership percentage (more than)	10.00%		10.00%

Employee Severance, Litigatio_3

Employee Severance, Litigation, and Other (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Restructuring Cost and Reserve [Line Items]
Employee severance	$ 14,021	$ 20,778	$ 18,806	$ 28,449
Litigation and opioid-related costs	13,822	7,629	28,361	10,437
Other	27,546	9,042	48,894	28,584
Total employee severance, litigation, and other	55,389	37,449	96,061	67,470
Acquisition-related and integration costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs	11,500		22,000	12,900
Business transformation efforts
Restructuring Cost and Reserve [Line Items]
Restructuring costs	9,900	6,000	16,900	10,700
Other restructuring initiatives
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 6,200	$ 3,100	$ 10,000	$ 5,000

Legal Matters and Contingenci_2

Legal Matters and Contingencies (Details) - USD ($)	1 Months Ended	3 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jul. 01, 2018
Commitments and Contingencies Disclosure [Abstract]
Annual fund amount total			$ 100,000,000
Estimated liability under the New York Opioid Stewardship Act	$ (22,000,000)	$ 22,000,000

Litigation Settlements (Details

Litigation Settlements (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Gain from antitrust litigation settlements	$ 52	$ 0.3	$ 139.3	$ 0.3

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2019	Sep. 30, 2018
Estimate of Fair Value Measurement | Level 2 inputs
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 3,932.2	$ 4,000.1
Reported Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	4,009.5	4,158.5
Money market | Estimate of Fair Value Measurement | Level 1 inputs
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 1,625	$ 1,050

Business Segment Information -

Business Segment Information - Segment Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 43,319,602	$ 41,033,858	$ 88,712,054	$ 81,500,190
Intersegment eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	(21,991)	(13,873)	(44,858)	(30,190)
Pharmaceutical Distribution Services | Operating segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	41,676,164	39,453,353	85,420,545	78,391,051
Other: | Operating segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	1,665,429	1,594,378	3,336,367	3,139,329
MWI Animal Health | Other: | Operating segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	947,293	933,003	1,901,877	1,891,575
Global Commercialization Services | Other: | Operating segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 718,136	$ 661,375	$ 1,434,490	$ 1,247,754

Business Segment Information _2

Business Segment Information - Segment Operating Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Total segment operating income	$ 47,565	$ 481,420	$ 525,388	$ 900,393
Operating segments
Segment Reporting Information [Line Items]
Total segment operating income	616,664	586,332	1,088,498	1,074,382
Intersegment eliminations
Segment Reporting Information [Line Items]
Total segment operating income	(249)	171	(556)	(236)
Pharmaceutical Distribution Services | Operating segments
Segment Reporting Information [Line Items]
Total segment operating income	517,034	489,106	890,241	877,288
Other: | Operating segments
Segment Reporting Information [Line Items]
Total segment operating income	$ 99,879	$ 97,055	$ 198,813	$ 197,330

Business Segment Information _3

Business Segment Information - Reconciliation of Segment Operating Income to Income (Loss) from Operations before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment operating income	$ 47,565	$ 481,420	$ 525,388	$ 900,393
Gain from antitrust litigation settlements	52,000	300	139,300	300
LIFO credit			69,834	0
Employee severance, litigation, and other	55,389	37,449	96,061	67,470
Impairment of long-lived assets	570,000	0	570,000	0
Other (income) loss	(14,494)	29,123	(11,397)	29,447
Interest expense, net	43,275	48,637	85,445	84,501
Loss on consolidation of equity investments	0	42,328	0	42,328
Loss on early retirement of debt	0	0	0	23,766
Income before income taxes	18,784	361,332	451,340	720,351
Operating segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment operating income	616,664	586,332	1,088,498	1,074,382
Segment reconciling items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Gain from antitrust litigation settlements	51,976	338	139,255	338
LIFO credit	66,805	0	69,834	0
PharMEDium remediation costs	(15,897)	(22,506)	(36,392)	(22,506)
New York State Opioid Stewardship Act	0	0	22,000	0
Acquisition-related intangibles amortization	(46,594)	(45,295)	(91,746)	(84,351)
Employee severance, litigation, and other	(55,389)	(37,449)	(96,061)	(67,470)
Impairment of long-lived assets	(570,000)	0	(570,000)	0
Loss on consolidation of equity investments	$ 0	$ 42,328	$ 0	$ 42,328

Business Segment Information _4

Business Segment Information - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Impairment of non-customer note receivable			$ 0	$ 30,000
Other Loss (Income)
Segment Reporting Information [Line Items]
Gain on sale of an equity investment	$ 13,700		$ 13,700
Impairment of non-customer note receivable		$ 30,000		$ 30,000

Uncategorized Items - abc-20190

Label	Element	Value
Accounting Standards Update 2014-09 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (2,584,000)
Accounting Standards Update 2014-09 [Member] | Noncontrolling Interest [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(1,102,000)
Accounting Standards Update 2014-09 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (1,482,000)