Cencora (COR) 10-Q 30 Jan 20 2020 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Dec. 31, 2019	Jan. 28, 2020
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Fiscal Year Focus	2020
Document Transition Report	false
Entity File Number	1-16671
Entity Registrant Name	AMERISOURCEBERGEN CORP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	23-3079390
Entity Address, Address Line One	1300 Morris Drive
Entity Address, City or Town	Chesterbrook,
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	19087-5594
City Area Code	610
Local Phone Number	727-7000
Entity Central Index Key	0001140859
Document Period End Date	Dec. 31, 2019
Trading Symbol	ABC
Title of 12(b) Security	Common stock
Security Exchange Name	NYSE
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--09-30
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		205,891,754
Amendment Flag	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Current assets:
Cash and cash equivalents	$ 3,232,604	$ 3,374,194
Accounts receivable, less allowances for returns and doubtful accounts: $1,365,577 as of December 31, 2019 and $1,222,906 as of September 30, 2019	12,568,816	12,386,879
Inventories	11,686,466	11,060,254
Right to recover asset	1,277,714	1,147,483
Prepaid expenses and other	189,216	163,244
Total current assets	28,954,816	28,132,054
Property and equipment, net	1,442,383	1,770,516
Goodwill	6,707,764	6,705,507
Other intangible assets	2,138,398	2,294,836
Other assets	773,377	269,067
TOTAL ASSETS	40,016,738	39,171,980
Current liabilities:
Accounts payable	29,181,860	28,385,074
Accrued expenses and other	916,107	1,057,208
Short-term debt	532,489	139,012
Total current liabilities	30,630,456	29,581,294
Long-term debt	3,636,114	4,033,880
Long-term financing obligation (Note 1)	0	320,518
Accrued income taxes	289,047	284,075
Deferred income taxes	1,895,453	1,860,195
Other liabilities	496,587	98,812
Commitments and contingencies (Note 10)
Stockholders’ equity:
Common stock, $0.01 par value - authorized, issued, and outstanding: 600,000,000 shares, 285,992,180 shares, and 205,778,204 shares as of December 31, 2019, respectively, and 600,000,000 shares, 285,295,170 shares, and 206,760,654 shares as of September 30, 2019, respectively	2,860	2,853
Additional paid-in capital	4,901,291	4,850,142
Retained earnings	4,375,181	4,235,491
Accumulated other comprehensive loss	(87,731)	(111,965)
Treasury stock, at cost: 80,213,976 shares as of December 31, 2019 and 78,534,516 shares as of September 30, 2019	(6,236,975)	(6,097,604)
Total AmerisourceBergen Corporation stockholders' equity	2,954,626	2,878,917
Noncontrolling interest	114,455	114,289
Total equity	3,069,081	2,993,206
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 40,016,738	$ 39,171,980

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Statement of Financial Position [Abstract]
Allowances for returns and doubtful accounts	$ 1,365,577	$ 1,222,906
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)	285,992,180	285,295,170
Common stock, outstanding (shares)	205,778,204	206,760,654
Treasury stock (shares)	80,213,976	78,534,516

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenue	$ 47,864,742	$ 45,392,452
Cost of goods sold	46,633,528	44,094,872
Gross profit	1,231,214	1,297,580
Operating expenses:
Distribution, selling, and administrative	685,953	656,585
Depreciation	69,244	75,362
Amortization	35,271	47,138
Employee severance, litigation, and other	39,309	40,672
Impairment of long-lived assets	138,000	0
Operating income	263,437	477,823
Other loss	2,842	3,097
Interest expense, net	31,007	42,170
Income before income taxes	229,588	432,556
Income tax expense	43,020	40,803
Net income	186,568	391,753
Net loss attributable to noncontrolling interest	1,072	1,899
Net income attributable to AmerisourceBergen Corporation	$ 187,640	$ 393,652
Earnings per share:
Basic (usd per share)	$ 0.91	$ 1.86
Diluted (usd per share)	$ 0.90	$ 1.84
Weighted average common shares outstanding:
Basic (shares)	206,008	212,054
Diluted (shares)	207,517	213,969
Cash dividends declared per share of common stock (usd per share)	$ 0.40	$ 0.40

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 186,568	$ 391,753
Other comprehensive income (loss)
Foreign currency translation adjustments	25,453	(11,374)
Other	19	(112)
Total other comprehensive income (loss)	25,472	(11,486)
Total comprehensive income	212,040	380,267
Comprehensive income attributable to noncontrolling interest	(166)	(245)
Comprehensive income attributable to AmerisourceBergen Corporation	$ 211,874	$ 380,022

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, 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)	391,753			393,652			(1,899)
Other comprehensive (loss) income	(11,486)				(13,630)		2,144
Cash dividends	(85,535)			(85,535)
Exercises of stock options	22,400	4	22,396
Share-based compensation expense	31,768		31,768
Purchases of common stock	(225,850)					(225,850)
Employee tax withholdings related to restricted share vesting	(5,654)					(5,654)
Other	(40)	2	(42)
Ending balance at Dec. 31, 2018	3,164,733	2,842	4,769,595	4,027,217	(92,883)	(5,658,318)	116,280
Beginning balance at Sep. 30, 2019	2,993,206	2,853	4,850,142	4,235,491	(111,965)	(6,097,604)	114,289
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	186,568			187,640			(1,072)
Other comprehensive (loss) income	25,472				24,234		1,238
Cash dividends	(83,088)			(83,088)
Exercises of stock options	20,113	3	20,110
Share-based compensation expense	31,374		31,374
Purchases of common stock	(129,775)					(129,775)
Employee tax withholdings related to restricted share vesting	(9,596)					(9,596)
Other	(331)	4	(335)
Ending balance at Dec. 31, 2019	$ 3,069,081	$ 2,860	$ 4,901,291	$ 4,375,181	$ (87,731)	$ (6,236,975)	$ 114,455

CONSOLIDATED STATEMENTS OF CH_2

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

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
OPERATING ACTIVITIES
Net income	$ 186,568	$ 391,753
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, including amounts charged to cost of goods sold	71,846	85,996
Amortization, including amounts charged to interest expense	37,499	49,236
Provision for doubtful accounts	2,189	8,007
Provision for deferred income taxes	29,355	46,246
Share-based compensation	31,374	31,768
LIFO expense (credit)	13,281	(3,029)
Impairment of long-lived assets	138,000	0
Other	17,476	(11,319)
Changes in operating assets and liabilities, excluding the effects of acquisitions:
Accounts receivable	(307,204)	(658,890)
Inventories	(630,980)	(898,775)
Prepaid expenses and other assets	(111)	(26,610)
Accounts payable	787,037	1,498,643
Income taxes payable	1,669	(18,792)
Accrued expenses and other liabilities	(235,189)	(15,266)
NET CASH PROVIDED BY OPERATING ACTIVITIES	142,810	478,968
INVESTING ACTIVITIES
Capital expenditures	(67,305)	(79,233)
Cost of acquired companies, net of cash acquired	0	(52,398)
Other	4,966	4,013
NET CASH USED IN INVESTING ACTIVITIES	(62,339)	(127,618)
FINANCING ACTIVITIES
Senior notes and other loan borrowings	18,538	424,684
Senior notes and other loan repayments	(29,023)	(428,079)
Borrowings under revolving and securitization credit facilities	50,584	97,449
Repayments under revolving and securitization credit facilities	(54,080)	(85,612)
Purchases of common stock	(135,128)	(239,008)
Exercises of stock options	20,113	22,400
Cash dividends on common stock	(83,088)	(85,535)
Tax withholdings related to restricted share vesting	(9,596)	(5,654)
Other	(381)	(4,355)
NET CASH USED IN FINANCING ACTIVITIES	(222,061)	(303,710)
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(141,590)	47,640
Cash and cash equivalents at beginning of period	3,374,194	2,492,516
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 3,232,604	$ 2,540,156

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Dec. 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 December 31, 2019 and the results of operations and cash flows for the interim periods ended December 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, 2019 . 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 February 2016, the FASB issued ASU No. 2016-02, "Leases (Topic 842)" ("ASU 2016-02" or "ASC 842")). 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 was effective for annual reporting periods beginning after December 15, 2018 and interim periods within those fiscal years. The Company adopted ASC 842 as of October 1, 2019 and adopted it using the modified retrospective approach. The Company elected the transition package of practical expedients provided within the amended guidance, which eliminated the requirements to reassess lease identification, lease classification, and initial direct costs for leases that commenced before the effective date. The Company also elected to combine lease and non-lease components and to exclude short-term leases from its consolidated balance sheets. The Company did not elect the hindsight practical expedient in determining the lease term. In connection with the adoption of ASC 842, the Company recognized operating lease liabilities of $562.1 million , right-of-use ("ROU") assets of $526.3 million , and a $35.1 million , net of tax of $9.6 million , cumulative adjustment to retained earnings. The Company's lease liabilities were based on the present value of the remaining minimum lease commitments using the Company's incremental borrowing rates as of October 1, 2019, and the Company's ROU assets were based upon the operating lease liabilities adjusted for prepaid and deferred rents. The cumulative adjustment to retained earnings was primarily the result of derecognizing assets of $266.0 million in Property and Equipment, Net and $324.8 million of financing obligations in Long-Term Financing Obligation and Accrued Expenses and Other, all of which was associated with leased assets where the Company was deemed the owner of the leased assets for accounting purposes. The Company finalized the impact that the amended lease guidance had on its systems, processes, and internal controls. The adoption of ASC 842 did not and will not have a material impact on its results of operations or cash flows. For the Company's lease accounting policy and other required disclosures, refer to Note 2. Recently Issued Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU No. 2016-13, "Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments" ("ASU 2016-13"). ASU 2016-13 requires financial assets measured at amortized cost to be presented at the net amount expected to be collected. The measurement of expected credit losses is based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectibility of the reported amounts. An entity must use judgment in determining the relevant information and estimation methods that are appropriate in its circumstances. ASU 2016-13 is effective for annual reporting periods beginning after December 15, 2019, including interim periods within those fiscal years, and a modified retrospective approach is required, with a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. Entities are permitted to adopt the standard early in fiscal years beginning after December 15, 2018. The Company is currently evaluating the impact of adopting this new accounting guidance. In December 2019, the FASB issued ASU No. 2019-12, "Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes" ("ASU 2019-12"). ASU 2019-12 removes certain exceptions to the general principles in ASC 740 in order to reduce the cost and complexity of its application. ASU 2019-12 is effective for annual reporting periods beginning after December 15, 2020, including interim periods within those fiscal years, with certain amendments applied on a modified retrospective basis, with a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption, and others prospectively. Early adoption of this guidance is permitted, including the adoption in any interim period for public companies for periods for which financial statements have not yet been issued. The Company is currently evaluating the impact of adopting this new accounting guidance. As of December 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.

Leases

Leases	3 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	Leases At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the facts and circumstances present. Leases are classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. At the lease commencement date, operating and finance lease liabilities and their corresponding ROU assets are recorded based on the present value of lease payments over the expected lease term. The interest rate implicit in lease contracts is typically not readily determinable and, as such, the Company uses its incremental borrowing rate to discount the lease liabilities, which is the rate incurred to borrow on a collateralized basis over a similar term in a similar economic environment. Certain adjustments to the ROU asset may be required for items such as incentives received. The Company does not recognize on the balance sheet leases with terms of one year or less. The Company has operating leases that are primarily comprised of buildings, office equipment, distribution center equipment, and vehicles. Some of the Company's leases include options to extend or early terminate the lease, which are included in the lease term when it is reasonably certain to exercise and there is a significant economic incentive to exercise that option. Certain lease agreements contain provisions for future rent increases. Lease payments included in the measurement of the lease liability comprise fixed payments. The Company combines lease and non-lease components as a single component. Operating lease cost is recognized over the expected lease term on a straight-line basis. Variable lease payments, which are primarily comprised of maintenance, taxes, and other payments based on usage, are recognized when the expense is incurred. The Company's leases do not contain residual value guarantees. The components of lease cost in the three months ended December 31, 2019 were as follows: (in thousands) Three months ended December 31, 2019 Operating lease cost $ 29,935 Short-term lease cost 1,526 Variable lease cost 4,856 Total lease cost $ 36,317 The Company recorded rental expense of $26.8 million in the three months ended December 31, 2018. The following summarizes balance sheet information related to operating leases: (in thousands, except for lease term and discount rate) December 31, 2019 Right of use assets Other assets $ 499,290 Lease liabilities Accrued expenses and other $ 97,935 Other long-term liabilities 440,124 Total lease liabilities $ 538,059 Weighted-average remaining lease term 7.56 years Weighted-average discount rate 3.81% Other cash flow information related to operating leases is as follows: (in thousands) Three months ended December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities Operating lease cash payments $ 29,100 Right-of-use assets obtained in exchange for lease liabilities New operating leases $ 5,918 Leases recognized upon adoption of ASC 842 $ 526,281 Future minimum rental payments under noncancellable operating leases were as follows: Payments Due by Fiscal Year (in thousands) As of December 31, 2019 2020 $ 89,675 2021 116,302 2022 111,367 2023 101,487 2024 93,647 Thereafter 453,893 Total future undiscounted lease payments 966,371 Less: Future payments for leases that have not yet commenced 1 (296,788 ) Less: Imputed interest (131,524 ) Total lease liabilities $ 538,059 1 The Company has certain leases that it has executed but it does not control the underlying assets; therefore, lease liabilities and ROU assets were not recorded on the Company's Consolidated Balance Sheet as of December 31, 2019. These future commitments primarily relate to the Company's new general corporate and administrative office. As previously disclosed in the Company's fiscal 2019 Annual Report on Form 10-K under the prior accounting guidance, the future minimum rental payments under noncancellable operating leases and financing obligations as of September 30, 2019 were as follows: Payments Due by Fiscal Year (in thousands) Operating Leases Financing Obligations 1 Total 2020 $ 94,958 $ 22,468 $ 117,426 2021 84,002 29,790 113,792 2022 72,224 36,914 109,138 2023 63,507 35,950 99,457 2024 56,377 35,276 91,653 Thereafter 177,267 270,410 447,677 Total minimum lease payments $ 548,335 $ 430,808 $ 979,143 1 Represents the portion of future minimum lease payments related to facility leases where the Company was determined to be the accounting owner (see Note 1 of the Notes to Consolidated Financial Statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2019 for a more detailed description of the Company's accounting for leases prior to the adoption of ASC 842). These payments were recognized as reductions to the financing obligation and as interest expense and excluded the future non-cash termination of the financing obligation.

Variable Interest Entity

Variable Interest Entity	3 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entity	Variable Interest Entity The Company has substantial governance rights over Profarma Distribuidora de Produtos Farmacêuticos S.A. ("Profarma"), which allow it to direct the activities that significantly impact Profarma’s economic performance. As such, the Company consolidates the operating results of Profarma in its consolidated financial statements. 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) December 31, September 30, Cash and cash equivalents $ 16,433 $ 9,431 Accounts receivables, net 164,917 154,491 Inventories 195,857 185,602 Prepaid expenses and other 69,176 64,119 Property and equipment, net 31,765 30,961 Goodwill 82,309 82,309 Other intangible assets 72,814 74,429 Other long-term assets 62,526 9,169 Total assets $ 695,797 $ 610,511 Accounts payable $ 196,340 $ 165,053 Accrued expenses and other 68,903 49,191 Short-term debt 100,962 106,439 Long-term debt 62,230 60,973 Deferred income taxes 38,023 42,371 Other long-term liabilities 48,209 5,303 Total liabilities $ 514,667 $ 429,330

Income Taxes

Income Taxes	3 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company files income tax returns in U.S. federal and state jurisdictions as well as various foreign jurisdictions. As of December 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 $125.2 million ( $92.7 million , net of federal benefit). If recognized, $74.5 million of these tax benefits would have reduced income tax expense and the effective tax rate. Included in this amount is $19.0 million of interest and penalties, which the Company records in Income Tax Expense in the Company's Consolidated Statements of Operations. In the three months ended December 31, 2019 , unrecognized tax benefits increased by $1.0 million . Over the next 12 months, it is reasonably possible that tax authority audit resolutions and the expiration of statutes of limitations could result in a reduction of unrecognized tax benefits of approximately $17.7 million . The Company's effective tax rates were 18.7% and 9.4% for the three months ended December 31, 2019 and 2018, respectively. The effective tax rate in the three months ended December 31, 2019 was lower than the U.S. statutory rate due to a higher mix of foreign earnings at lower tax rates in Switzerland and Ireland, since U.S. earnings were lower principally due to the $138.0 million impairment of long-lived assets (see Note 5 of the Notes to Consolidated Financial Statements). The effective tax rate in the three months ended December 31, 2018 benefited from a $37.0 million decrease to the Company's finalization of the estimated transition tax liability related to the Tax Cuts and Jobs Act and was favorably impacted by the Company's international businesses in Switzerland and Ireland.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	3 Months Ended
	Dec. 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 three months ended December 31, 2019 : (in thousands) Pharmaceutical Distribution Services Other Total Goodwill as of September 30, 2019 $ 4,852,775 $ 1,852,732 $ 6,705,507 Foreign currency translation — 2,257 2,257 Goodwill as of December 31, 2019 $ 4,852,775 $ 1,854,989 $ 6,707,764 The following is a summary of other intangible assets: December 31, 2019 September 30, 2019 (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 $ 685,366 $ — $ 685,366 $ 685,324 $ — $ 685,324 Finite-lived: Customer relationships 13 years 1,816,946 (501,862 ) 1,315,084 1,931,212 (489,471 ) 1,441,741 Trade names and other 13 years 243,667 (105,719 ) 137,948 271,521 (103,750 ) 167,771 Total other intangible assets $ 2,745,979 $ (607,581 ) $ 2,138,398 $ 2,888,057 $ (593,221 ) $ 2,294,836 Amortization expense for finite-lived intangible assets was $35.3 million and $47.1 million in the three months ended December 31, 2019 and 2018 , respectively. Amortization expense for finite-lived intangible assets is estimated to be $126.0 million in fiscal 2020 , $118.7 million in fiscal 2021 , $117.0 million in fiscal 2022 , $115.6 million in fiscal 2023 , $114.6 million in fiscal 2024 , and $896.5 million thereafter. As a result of the continued suspension of the production activities at PharMEDium Healthcare Holdings, Inc.'s ("PharMEDium") compounding facility located in Memphis, Tennessee, certain regulatory matters, ongoing operational challenges, and lower-than-expected operating results, the Company updated its recoverability assessment of PharMEDium’s long-lived assets as of December 31, 2019. The recoverability assessment was based upon comparing PharMEDium's forecasted undiscounted cash flows to the carrying value of its asset group. 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 December 31, 2019. The forecasted undiscounted cash flows as of December 31, 2019 were lower than the forecasted undiscounted cash flows as of September 30, 2019 due to a change in weighting of multiple strategic alternatives and lower operating results in the three months ended December 31, 2019 compared to expectations. The Company then performed an impairment test by comparing the PharMEDium asset group's fair value of $145 million to its carrying value, which resulted in a $138.0 million impairment loss. Significant assumptions used in estimating the fair value of PharMEDium's asset group included (i) a 17% discount rate, which contemplated a higher risk at PharMEDium; (ii) the period in which PharMEDium will resume production at or near capacity; and (iii) the estimated EBITDA (earnings before interest, taxes, depreciation, and amortization) 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 (see Note 14). This represents a Level 3 nonrecurring fair value measurement. The Company allocated $123.2 million of the impairment to finite-lived intangibles, $11.6 million of the impairment to property and equipment, and $3.2 million to ROU assets.

Debt

Debt	3 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Debt	Debt Debt consisted of the following: (in thousands) December 31, September 30, Revolving credit note $ — $ — Term loan due in 2020 399,819 399,778 Overdraft facility due 2021 (£30,000) 31,708 32,573 Receivables securitization facility due 2022 350,000 350,000 Multi-currency revolving credit facility due 2024 — — $500,000, 3.50% senior notes due 2021 499,037 498,908 $500,000, 3.40% senior notes due 2024 497,866 497,744 $500,000, 3.25% senior notes due 2025 496,481 496,311 $750,000, 3.45% senior notes due 2027 743,309 743,099 $500,000, 4.25% senior notes due 2045 494,568 494,514 $500,000, 4.30% senior notes due 2047 492,555 492,488 Nonrecourse debt 163,260 167,477 Total debt 4,168,603 4,172,892 Less AmerisourceBergen Corporation current portion 431,527 32,573 Less nonrecourse current portion 100,962 106,439 Total, net of current portion $ 3,636,114 $ 4,033,880 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 is scheduled to expire in September 2024 , with a syndicate of lenders. 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 112.5 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 December 31, 2019 ) and from 0 basis points to 12.5 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 12.5 basis points , annually, of the total commitment ( 9 basis points as of December 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 December 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 December 31, 2019 . Receivables Securitization Facility The Company has a $1,450 million receivables securitization facility ("Receivables Securitization Facility"), which is scheduled to expire in September 2022 . 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 December 31, 2019 . 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. 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	3 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Stockholders' Equity and Earnings per Share	Stockholders’ Equity and Earnings per Share In October 2018, 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 three months ended December 31, 2019 , the Company purchased 1.6 million shares of its common stock for a total of $129.8 million , which included $9.4 million of December 2019 purchases that cash settled in January 2020 and excluded $14.8 million of September 2019 purchases that cash settled in October 2019. As of December 31, 2019 , the Company had $331.4 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 (in thousands) 2019 2018 Weighted average common shares outstanding - basic 206,008 212,054 Dilutive effect of stock options and restricted stock units 1,509 1,915 Weighted average common shares outstanding - diluted 207,517 213,969 The potentially dilutive stock options and restricted stock units that were antidilutive for the three months ended December 31, 2019 and 2018 were 4.4 million and 3.8 million

Related Party Transactions

Related Party Transactions	3 Months Ended
	Dec. 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 $15.6 billion and $15.3 billion in the three months ended December 31, 2019 and 2018, respectively. The Company’s receivable from WBA, net of incentives, was $6.5 billion and $6.1 billion as of December 31, 2019 and September 30, 2019 , respectively.

Employee Severance, Litigation,

Employee Severance, Litigation, and Other	3 Months Ended
	Dec. 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 (in thousands) 2019 2018 Employee severance $ 839 $ 4,784 Litigation and opioid-related costs 24,666 14,539 Acquisition-related deal and integration costs 455 10,589 Business transformation efforts 8,460 6,979 Other restructuring initiatives 4,889 3,781 Total employee severance, litigation, and other $ 39,309 $ 40,672 Employee severance in the three months ended December 31, 2018 included costs primarily related to position eliminations resulting from our business transformation efforts and restructuring activities related to our consulting business. Litigation and opioid-related costs in the three months ended December 31, 2019 and 2018 related to legal fees in connection with opioid lawsuits and investigations. Acquisition-related deal and integration costs in the three months ended December 31, 2018 primarily related to the integration of H.D. Smith. Integration costs primarily included costs to transition servicing legacy H.D. Smith customers to existing Company distribution facilities and operating systems. Business transformation efforts in the three months ended December 31, 2019 and 2018 primarily related to costs associated with reorganizing the Company to further align the organization to its customers' needs. The majority of these costs related to services provided by third-party consultants.

Legal Matters and Contingencies

Legal Matters and Contingencies	3 Months Ended
	Dec. 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, stockholder demands, and other disputes, including antitrust, commercial, 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. 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 agreement obligations, consent decrees, and/or other civil and criminal penalties. From time to time, the Company is also involved in disputes with its customers, which the Company generally seeks to resolve through commercial negotiations. If negotiations are unsuccessful, the parties may litigate the dispute or otherwise attempt to settle the matter. 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. 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 certain subsidiaries, such as AmerisourceBergen Drug Corporation ("ABDC") and H.D. Smith), pharmaceutical manufacturers, retail chains, medical practices, and physicians relating to the distribution of prescription opioid pain medications. 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 and continue to be 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. 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. In April 2018, the Court issued an order creating a litigation track, which includes dispositive motion practice, discovery, and trials in certain bellwether jurisdictions. On December 31, 2018, the Court issued an order selecting two additional cases for a second bellwether discovery and trial track. In November 2019 and January 2020, the Court filed Suggestions of Remand with the Judicial Panel on Multidistrict Litigation that, if granted, would result in four cases, including the two additional bellwether cases, being transferred from the MDL back to federal courts in California, Oklahoma, and West Virginia for the completion of discovery, motion practice, and trial. The two West Virginia cases have now been remanded from the MDL to federal court in West Virginia. Certain defendants, including ABDC, have opposed the Suggestions of Remand for the California and Oklahoma cases. The timing of discovery, motion practice, and trials for these four cases has not yet been determined. On October 21, 2019, the Company announced an agreement in principle with two Ohio counties, Cuyahoga and Summit, to settle all claims brought by the two counties against the Company in the first track of the MDL. All claims against the Company were dismissed with prejudice pursuant to the settlement. Pursuant to this settlement, the Company made a payment of $66.7 million in December 2019. The Company had previously recorded a charge of $66.7 million in the fourth quarter of the fiscal year ended September 30, 2019 within Employee Severance, Litigation and Other in its Statement of Operations and in Accrued Expenses and Other on the Company’s Consolidated Balance Sheet. 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. On October 21, 2019, the Attorneys General for North Carolina, Pennsylvania, Tennessee, and Texas announced certain proposed settlement terms intended to provide a potential framework for a global resolution of the MDL and other related state court litigation, including cases currently filed and that could be filed. The attorneys general's announcement outlined that the largest U.S. pharmaceutical distributors would be expected to pay an aggregate amount of up to $18.0 billion over 18 years, of which the Company's portion would be 31.0% , in addition to the development and participation in a program for free or rebated distribution of opioid-abuse medications for a period of 10 years and the implementation of industry-wide changes to be specified to controlled substance anti-diversion programs. The Company is currently engaged in discussions that include the four attorneys general and other parties with the objective of reaching potential terms for a global resolution. The Company is also engaged in related discussions with plaintiffs' lawyers representing local governments and other parties with the same goal of reaching a global resolution with all parties. If agreed, the potential terms for a global resolution would then need to be presented to numerous other states and local governments, and a significant number of such jurisdictions would need to accept the proposed terms in order to achieve an agreement in principle that would provide the finality that the Company requires from a global resolution. Given the large number of parties involved, the complexity and difficulty of the underlying issues, and the resulting uncertainty of achieving a potential global resolution, the Company continues to litigate and prepare for trial in the cases pending in the MDL as well as in state courts where lawsuits have been filed, and intends to continue to vigorously defend itself in all such cases. A liability associated with a global resolution has not been recognized as of December 31, 2019, since the Company is unable to predict the outcome of settlement discussions with the states and local governments that will need to participate and, therefore, a global resolution cannot be considered probable. Furthermore, significant uncertainty remains with regard to whether such matters will proceed to trial, and, given the inherent uncertainty related to such litigation, the Company is not in a position to assess the likely outcome, and therefore unable to estimate the range of possible loss. In June 2019, attorneys for some of the plaintiffs filed a motion proposing a procedure to certify a nationwide "negotiation class" of cities and counties for the purpose of negotiating and settling with defendants engaged in the nationwide manufacturing, sale, or distribution of opioids. The attorneys subsequently withdrew the motion and refiled an amended motion on July 9, 2019. The Court granted the motion on September 11, 2019 and certain defendants, including ABDC, are appealing. A trial in New York state for cases brought by Nassau and Suffolk Counties and the New York Attorney General against a variety of defendants, including the Company, is scheduled to begin on March 20, 2020. This trial is not part of the MDL. 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, other pharmaceutical wholesale distributors have faced shareholder derivative suits alleging violations of fiduciary duties in connection with the oversight of the distribution of controlled substances. 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. Since July 2017, the Company has received subpoenas from several U.S. Attorney's Offices, including grand jury subpoenas from the U.S. Attorney's Office for the District of New Jersey ("USAO-NJ") and the U.S. Attorney's Office for the Eastern District of New York ("USAO-EDNY"). Those subpoenas request the production of a broad range of documents pertaining to the Company's distribution of controlled substances through its various subsidiaries, including ABDC, and its diversion control programs. The Company has been engaged in discussions with the various U.S. Attorney’s Offices, including the Health Care and Government Fraud Unit of the Criminal Division of the U.S. Attorney's Office for the District of New Jersey, 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. On May 17, 2019, PharMEDium reached an agreement on the terms of the Consent Decree with the FDA and the DOJ that was entered by the United States District Court for the Northern District of Illinois on May 22, 2019. The Consent Decree permits commercial operations to continue at PharMEDium’s Dayton, New Jersey and Sugar Land, Texas compounding facilities and administrative operations to continue at its Lake Forest, Illinois headquarters subject to compliance with requirements set forth therein. As required by the Consent Decree, initial audit inspections were conducted by an independent cGMP expert of the Dayton and Sugar Land facilities. The cGMP expert has notified the FDA that all of the short-term corrective actions taken are acceptable. The Company has submitted to the FDA several additional longer-term corrective actions, and the independent cGMP expert will assess the effectiveness of the implementation of these items in future audits. Additional audit inspections by the independent cGMP expert of the Sugar Land and Dayton facilities are required at least annually for a period of four years. The Consent Decree also establishes requirements that must be satisfied prior to the resumption of commercial operations at the Memphis, Tennessee facility. The requirements include a work plan approved by the FDA and an audit inspection and certification by an independent cGMP expert that the facilities, methods and controls at the Memphis facility and PharMEDium’s Lake Forest, Illinois headquarters comply with the Consent Decree. If PharMEDium receives written notification from the FDA of compliance with the requirements to resume operations at the Memphis facility, additional audit inspections are required for five years, during which time PharMEDium must correct any deviations from the Consent Decree observed by the independent cGMP expert. After five years, PharMEDium may petition the district court for full relief from the Consent Decree, or for specific relief with regard to one or more facilities. If, at the time of such petition, all obligations under the Consent Decree with respect to the specific facilities for which PharMEDium is seeking relief have been satisfied, and there has been continuous compliance with the Consent Decree for at least five years, the federal government will not oppose the petition, and PharMEDium may request that the district court grant such relief. 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 (see Note 14). Subpoenas, Ongoing Investigations, and Other Contingencies 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 ("U.S. Bio") received a subpoena for information from the 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. The case was unsealed in April 2019 and counsel for the relator filed an amended complaint under seal with the USAO-EDNY. In December 2019, the government filed a notice that it was again declining to intervene in the action. The Court has ordered the relator's complaint against the Company, including subsidiaries AmerisourceBergen Specialty Group, LLC and U.S. Bio, to be unsealed and the Company's response is due by February 28, 2020. On October 11, 2019, Teamsters Local 443 Health Services & Insurance Plan, St. Paul Electrical Construction Pension Plan, St. Paul Electrical Construction Workers Supplemental Pension Plan (2014 Restatement), Retirement Medical Funding Plan for the St. Paul Electrical Workers, and San Antonio Fire & Police Pension Fund filed a complaint for a purported derivative action in the Delaware Court of Chancery against the Company and certain of its officers and directors (collectively, "Defendants"). The complaint alleges that the Defendants breached their fiduciary duties by allegedly failing to oversee the compliance by certain of the Company's subsidiaries (including the Company's former subsidiary Medical Initiatives, Inc. ("MII"), which voluntarily ceased operations in 2014) with federal regulations, allegedly resulting in the payment of fines and penalties in connection with the settlements with the USAO-EDNY in fiscal 2017 and 2018 that resolved claims arising from MII's pre-filled syringe program. On December 20, 2019, Defendants filed a motion to dismiss the complaint, which remains pending before the Delaware Court of Chancery. 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. In December 2019, Reliable Pharmacy, together with other retail pharmacies and North Sunflower Medical Center, filed a civil antitrust complaint against multiple generic drug manufacturers, and also included claims against the Company and other drug distributors. The case is filed as a putative class action and plaintiffs purport to represent a class of drug purchasers including other retail pharmacies and healthcare providers. The complaint alleges that the Company and other drug distributors participated in a conspiracy to fix prices, allocate markets and rig bids regarding generic drugs. The complaint has not yet been served on the Company. 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. The Company recognized gains of $8.5 million and $87.3 million during the three months ended December 31, 2019 and 2018, respectively, 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	3 Months Ended
	Dec. 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, stockholder demands, and other disputes, including antitrust, commercial, 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. 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 agreement obligations, consent decrees, and/or other civil and criminal penalties. From time to time, the Company is also involved in disputes with its customers, which the Company generally seeks to resolve through commercial negotiations. If negotiations are unsuccessful, the parties may litigate the dispute or otherwise attempt to settle the matter. 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. 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 certain subsidiaries, such as AmerisourceBergen Drug Corporation ("ABDC") and H.D. Smith), pharmaceutical manufacturers, retail chains, medical practices, and physicians relating to the distribution of prescription opioid pain medications. 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 and continue to be 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. 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. In April 2018, the Court issued an order creating a litigation track, which includes dispositive motion practice, discovery, and trials in certain bellwether jurisdictions. On December 31, 2018, the Court issued an order selecting two additional cases for a second bellwether discovery and trial track. In November 2019 and January 2020, the Court filed Suggestions of Remand with the Judicial Panel on Multidistrict Litigation that, if granted, would result in four cases, including the two additional bellwether cases, being transferred from the MDL back to federal courts in California, Oklahoma, and West Virginia for the completion of discovery, motion practice, and trial. The two West Virginia cases have now been remanded from the MDL to federal court in West Virginia. Certain defendants, including ABDC, have opposed the Suggestions of Remand for the California and Oklahoma cases. The timing of discovery, motion practice, and trials for these four cases has not yet been determined. On October 21, 2019, the Company announced an agreement in principle with two Ohio counties, Cuyahoga and Summit, to settle all claims brought by the two counties against the Company in the first track of the MDL. All claims against the Company were dismissed with prejudice pursuant to the settlement. Pursuant to this settlement, the Company made a payment of $66.7 million in December 2019. The Company had previously recorded a charge of $66.7 million in the fourth quarter of the fiscal year ended September 30, 2019 within Employee Severance, Litigation and Other in its Statement of Operations and in Accrued Expenses and Other on the Company’s Consolidated Balance Sheet. 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. On October 21, 2019, the Attorneys General for North Carolina, Pennsylvania, Tennessee, and Texas announced certain proposed settlement terms intended to provide a potential framework for a global resolution of the MDL and other related state court litigation, including cases currently filed and that could be filed. The attorneys general's announcement outlined that the largest U.S. pharmaceutical distributors would be expected to pay an aggregate amount of up to $18.0 billion over 18 years, of which the Company's portion would be 31.0% , in addition to the development and participation in a program for free or rebated distribution of opioid-abuse medications for a period of 10 years and the implementation of industry-wide changes to be specified to controlled substance anti-diversion programs. The Company is currently engaged in discussions that include the four attorneys general and other parties with the objective of reaching potential terms for a global resolution. The Company is also engaged in related discussions with plaintiffs' lawyers representing local governments and other parties with the same goal of reaching a global resolution with all parties. If agreed, the potential terms for a global resolution would then need to be presented to numerous other states and local governments, and a significant number of such jurisdictions would need to accept the proposed terms in order to achieve an agreement in principle that would provide the finality that the Company requires from a global resolution. Given the large number of parties involved, the complexity and difficulty of the underlying issues, and the resulting uncertainty of achieving a potential global resolution, the Company continues to litigate and prepare for trial in the cases pending in the MDL as well as in state courts where lawsuits have been filed, and intends to continue to vigorously defend itself in all such cases. A liability associated with a global resolution has not been recognized as of December 31, 2019, since the Company is unable to predict the outcome of settlement discussions with the states and local governments that will need to participate and, therefore, a global resolution cannot be considered probable. Furthermore, significant uncertainty remains with regard to whether such matters will proceed to trial, and, given the inherent uncertainty related to such litigation, the Company is not in a position to assess the likely outcome, and therefore unable to estimate the range of possible loss. In June 2019, attorneys for some of the plaintiffs filed a motion proposing a procedure to certify a nationwide "negotiation class" of cities and counties for the purpose of negotiating and settling with defendants engaged in the nationwide manufacturing, sale, or distribution of opioids. The attorneys subsequently withdrew the motion and refiled an amended motion on July 9, 2019. The Court granted the motion on September 11, 2019 and certain defendants, including ABDC, are appealing. A trial in New York state for cases brought by Nassau and Suffolk Counties and the New York Attorney General against a variety of defendants, including the Company, is scheduled to begin on March 20, 2020. This trial is not part of the MDL. 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, other pharmaceutical wholesale distributors have faced shareholder derivative suits alleging violations of fiduciary duties in connection with the oversight of the distribution of controlled substances. 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. Since July 2017, the Company has received subpoenas from several U.S. Attorney's Offices, including grand jury subpoenas from the U.S. Attorney's Office for the District of New Jersey ("USAO-NJ") and the U.S. Attorney's Office for the Eastern District of New York ("USAO-EDNY"). Those subpoenas request the production of a broad range of documents pertaining to the Company's distribution of controlled substances through its various subsidiaries, including ABDC, and its diversion control programs. The Company has been engaged in discussions with the various U.S. Attorney’s Offices, including the Health Care and Government Fraud Unit of the Criminal Division of the U.S. Attorney's Office for the District of New Jersey, 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. On May 17, 2019, PharMEDium reached an agreement on the terms of the Consent Decree with the FDA and the DOJ that was entered by the United States District Court for the Northern District of Illinois on May 22, 2019. The Consent Decree permits commercial operations to continue at PharMEDium’s Dayton, New Jersey and Sugar Land, Texas compounding facilities and administrative operations to continue at its Lake Forest, Illinois headquarters subject to compliance with requirements set forth therein. As required by the Consent Decree, initial audit inspections were conducted by an independent cGMP expert of the Dayton and Sugar Land facilities. The cGMP expert has notified the FDA that all of the short-term corrective actions taken are acceptable. The Company has submitted to the FDA several additional longer-term corrective actions, and the independent cGMP expert will assess the effectiveness of the implementation of these items in future audits. Additional audit inspections by the independent cGMP expert of the Sugar Land and Dayton facilities are required at least annually for a period of four years. The Consent Decree also establishes requirements that must be satisfied prior to the resumption of commercial operations at the Memphis, Tennessee facility. The requirements include a work plan approved by the FDA and an audit inspection and certification by an independent cGMP expert that the facilities, methods and controls at the Memphis facility and PharMEDium’s Lake Forest, Illinois headquarters comply with the Consent Decree. If PharMEDium receives written notification from the FDA of compliance with the requirements to resume operations at the Memphis facility, additional audit inspections are required for five years, during which time PharMEDium must correct any deviations from the Consent Decree observed by the independent cGMP expert. After five years, PharMEDium may petition the district court for full relief from the Consent Decree, or for specific relief with regard to one or more facilities. If, at the time of such petition, all obligations under the Consent Decree with respect to the specific facilities for which PharMEDium is seeking relief have been satisfied, and there has been continuous compliance with the Consent Decree for at least five years, the federal government will not oppose the petition, and PharMEDium may request that the district court grant such relief. 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 (see Note 14). Subpoenas, Ongoing Investigations, and Other Contingencies 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 ("U.S. Bio") received a subpoena for information from the 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. The case was unsealed in April 2019 and counsel for the relator filed an amended complaint under seal with the USAO-EDNY. In December 2019, the government filed a notice that it was again declining to intervene in the action. The Court has ordered the relator's complaint against the Company, including subsidiaries AmerisourceBergen Specialty Group, LLC and U.S. Bio, to be unsealed and the Company's response is due by February 28, 2020. On October 11, 2019, Teamsters Local 443 Health Services & Insurance Plan, St. Paul Electrical Construction Pension Plan, St. Paul Electrical Construction Workers Supplemental Pension Plan (2014 Restatement), Retirement Medical Funding Plan for the St. Paul Electrical Workers, and San Antonio Fire & Police Pension Fund filed a complaint for a purported derivative action in the Delaware Court of Chancery against the Company and certain of its officers and directors (collectively, "Defendants"). The complaint alleges that the Defendants breached their fiduciary duties by allegedly failing to oversee the compliance by certain of the Company's subsidiaries (including the Company's former subsidiary Medical Initiatives, Inc. ("MII"), which voluntarily ceased operations in 2014) with federal regulations, allegedly resulting in the payment of fines and penalties in connection with the settlements with the USAO-EDNY in fiscal 2017 and 2018 that resolved claims arising from MII's pre-filled syringe program. On December 20, 2019, Defendants filed a motion to dismiss the complaint, which remains pending before the Delaware Court of Chancery. 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. In December 2019, Reliable Pharmacy, together with other retail pharmacies and North Sunflower Medical Center, filed a civil antitrust complaint against multiple generic drug manufacturers, and also included claims against the Company and other drug distributors. The case is filed as a putative class action and plaintiffs purport to represent a class of drug purchasers including other retail pharmacies and healthcare providers. The complaint alleges that the Company and other drug distributors participated in a conspiracy to fix prices, allocate markets and rig bids regarding generic drugs. The complaint has not yet been served on the Company. 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. The Company recognized gains of $8.5 million and $87.3 million during the three months ended December 31, 2019 and 2018, respectively, 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	3 Months Ended
	Dec. 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 December 31, 2019 and September 30, 2019 approximate fair value based upon the relatively short-term nature of these financial instruments. Within Cash and Cash Equivalents, the Company had $1,006.0 million of investments in money market accounts as of December 31, 2019 and had $1,552.0 million of investments in money market accounts as of September 30, 2019 . 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 December 31, 2019 were $3,636.1 million and $3,756.6 million , respectively. The recorded amount of long-term debt and the corresponding fair value as of September 30, 2019 were $4,033.9 million and $4,158.4 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	3 Months Ended
	Dec. 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 (in thousands) 2019 2018 Pharmaceutical Distribution Services $ 46,036,828 $ 43,744,381 Other: MWI Animal Health 1,028,318 954,584 Global Commercialization Services 818,666 716,354 Total Other 1,846,984 1,670,938 Intersegment eliminations (19,070 ) (22,867 ) Revenue $ 47,864,742 $ 45,392,452 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 (in thousands) 2019 2018 Pharmaceutical Distribution Services $ 391,694 $ 373,207 Other 104,479 98,934 Intersegment eliminations (907 ) (307 ) Total segment operating income $ 495,266 $ 471,834 The following reconciles total segment operating income to income before income taxes for the periods indicated: Three months ended (in thousands) 2019 2018 Total segment operating income $ 495,266 $ 471,834 Gain from antitrust litigation settlements 8,492 87,279 LIFO (expense) credit (13,281 ) 3,029 PharMEDium remediation costs (16,165 ) (20,495 ) New York State Opioid Stewardship Act — 22,000 Acquisition-related intangibles amortization (33,566 ) (45,152 ) Employee severance, litigation, and other (39,309 ) (40,672 ) Impairment of long-lived assets (138,000 ) — Operating income 263,437 477,823 Other loss 2,842 3,097 Interest expense, net 31,007 42,170 Income before income taxes $ 229,588 $ 432,556 Segment operating income is evaluated by the chief operating decision maker of the Company before gain from antitrust litigation settlements; LIFO (expense) credit; PharMEDium remediation costs; New York State Opioid Stewardship Act; acquisition-related intangibles amortization; employee severance, litigation, and other; and impairment of long-lived assets. All corporate office expenses are allocated to the operating segment level.

Subsequent Events

Subsequent Events	3 Months Ended
	Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Dividend Increase In January 2020, the Company's board of directors increased the quarterly dividend paid on common stock by 5% and declared a regular quarterly cash dividend of $0.42 payable on March 2, 2020 to shareholders of record on February 14, 2020 . PharMEDium In late January 2020 the Company decided to exit the PharMEDium compounding business and as a result, the Company will cease all commercial and administrative operations related to this business. The decision to exit the PharMEDium business was due to a number of factors including, but not limited to, ongoing operational, regulatory, and commercial challenges, such as PharMEDium's decision in January 2020 to suspend production at the compounding facility in New Jersey pending facility upgrades related to the air handling and filtration systems. In addition to the PharMEDium impairment charge of $138.0 million recognized in the three months ended December 31, 2019 (see Note 5), the Company expects it will impair the majority of the remaining $55 million of PharMEDium tangible assets and all of the remaining $185 million of PharMEDium intangible assets in the three months ending March 31, 2020. Additionally, the Company will incur other costs, such as employee separation costs, in connection with exiting the PharMEDium compounding business during the fiscal year ending September 30, 2020 estimated to total approximately $80 million to $100 million . As a result of the decision to exit the PharMEDium compounding business, the Company expects to claim an ordinary income tax deduction and estimates that it will realize a cash tax benefit in fiscal 2020 through fiscal 2022 totaling approximately $500 million to $600 million .

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Dec. 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 December 31, 2019 and the results of operations and cash flows for the interim periods ended December 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, 2019 .
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 February 2016, the FASB issued ASU No. 2016-02, "Leases (Topic 842)" ("ASU 2016-02" or "ASC 842")). 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 was effective for annual reporting periods beginning after December 15, 2018 and interim periods within those fiscal years. The Company adopted ASC 842 as of October 1, 2019 and adopted it using the modified retrospective approach. The Company elected the transition package of practical expedients provided within the amended guidance, which eliminated the requirements to reassess lease identification, lease classification, and initial direct costs for leases that commenced before the effective date. The Company also elected to combine lease and non-lease components and to exclude short-term leases from its consolidated balance sheets. The Company did not elect the hindsight practical expedient in determining the lease term. In connection with the adoption of ASC 842, the Company recognized operating lease liabilities of $562.1 million , right-of-use ("ROU") assets of $526.3 million , and a $35.1 million , net of tax of $9.6 million , cumulative adjustment to retained earnings. The Company's lease liabilities were based on the present value of the remaining minimum lease commitments using the Company's incremental borrowing rates as of October 1, 2019, and the Company's ROU assets were based upon the operating lease liabilities adjusted for prepaid and deferred rents. The cumulative adjustment to retained earnings was primarily the result of derecognizing assets of $266.0 million in Property and Equipment, Net and $324.8 million of financing obligations in Long-Term Financing Obligation and Accrued Expenses and Other, all of which was associated with leased assets where the Company was deemed the owner of the leased assets for accounting purposes. The Company finalized the impact that the amended lease guidance had on its systems, processes, and internal controls. The adoption of ASC 842 did not and will not have a material impact on its results of operations or cash flows. For the Company's lease accounting policy and other required disclosures, refer to Note 2. Recently Issued Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU No. 2016-13, "Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments" ("ASU 2016-13"). ASU 2016-13 requires financial assets measured at amortized cost to be presented at the net amount expected to be collected. The measurement of expected credit losses is based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectibility of the reported amounts. An entity must use judgment in determining the relevant information and estimation methods that are appropriate in its circumstances. ASU 2016-13 is effective for annual reporting periods beginning after December 15, 2019, including interim periods within those fiscal years, and a modified retrospective approach is required, with a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. Entities are permitted to adopt the standard early in fiscal years beginning after December 15, 2018. The Company is currently evaluating the impact of adopting this new accounting guidance. In December 2019, the FASB issued ASU No. 2019-12, "Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes" ("ASU 2019-12"). ASU 2019-12 removes certain exceptions to the general principles in ASC 740 in order to reduce the cost and complexity of its application. ASU 2019-12 is effective for annual reporting periods beginning after December 15, 2020, including interim periods within those fiscal years, with certain amendments applied on a modified retrospective basis, with a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption, and others prospectively. Early adoption of this guidance is permitted, including the adoption in any interim period for public companies for periods for which financial statements have not yet been issued. The Company is currently evaluating the impact of adopting this new accounting guidance. As of December 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.

Leases (Tables)

Leases (Tables)	3 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Lease cost	Other cash flow information related to operating leases is as follows: (in thousands) Three months ended December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities Operating lease cash payments $ 29,100 Right-of-use assets obtained in exchange for lease liabilities New operating leases $ 5,918 Leases recognized upon adoption of ASC 842 $ 526,281 The components of lease cost in the three months ended December 31, 2019 were as follows: (in thousands) Three months ended December 31, 2019 Operating lease cost $ 29,935 Short-term lease cost 1,526 Variable lease cost 4,856 Total lease cost $ 36,317
Summarized balance sheet information	The following summarizes balance sheet information related to operating leases: (in thousands, except for lease term and discount rate) December 31, 2019 Right of use assets Other assets $ 499,290 Lease liabilities Accrued expenses and other $ 97,935 Other long-term liabilities 440,124 Total lease liabilities $ 538,059 Weighted-average remaining lease term 7.56 years Weighted-average discount rate 3.81%
Future minimum rental payments, operating leases	Future minimum rental payments under noncancellable operating leases were as follows: Payments Due by Fiscal Year (in thousands) As of December 31, 2019 2020 $ 89,675 2021 116,302 2022 111,367 2023 101,487 2024 93,647 Thereafter 453,893 Total future undiscounted lease payments 966,371 Less: Future payments for leases that have not yet commenced 1 (296,788 ) Less: Imputed interest (131,524 ) Total lease liabilities $ 538,059 1 The Company has certain leases that it has executed but it does not control the underlying assets; therefore, lease liabilities and ROU assets were not recorded on the Company's Consolidated Balance Sheet as of December 31, 2019. These future commitments primarily relate to the Company's new general corporate and administrative office.
Future minimum rental payments, operating leases	As previously disclosed in the Company's fiscal 2019 Annual Report on Form 10-K under the prior accounting guidance, the future minimum rental payments under noncancellable operating leases and financing obligations as of September 30, 2019 were as follows: Payments Due by Fiscal Year (in thousands) Operating Leases Financing Obligations 1 Total 2020 $ 94,958 $ 22,468 $ 117,426 2021 84,002 29,790 113,792 2022 72,224 36,914 109,138 2023 63,507 35,950 99,457 2024 56,377 35,276 91,653 Thereafter 177,267 270,410 447,677 Total minimum lease payments $ 548,335 $ 430,808 $ 979,143 1 Represents the portion of future minimum lease payments related to facility leases where the Company was determined to be the accounting owner (see Note 1 of the Notes to Consolidated Financial Statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2019 for a more detailed description of the Company's accounting for leases prior to the adoption of ASC 842). These payments were recognized as reductions to the financing obligation and as interest expense and excluded the future non-cash termination of the financing obligation.
Future minimum rental payments, financing obligations	As previously disclosed in the Company's fiscal 2019 Annual Report on Form 10-K under the prior accounting guidance, the future minimum rental payments under noncancellable operating leases and financing obligations as of September 30, 2019 were as follows: Payments Due by Fiscal Year (in thousands) Operating Leases Financing Obligations 1 Total 2020 $ 94,958 $ 22,468 $ 117,426 2021 84,002 29,790 113,792 2022 72,224 36,914 109,138 2023 63,507 35,950 99,457 2024 56,377 35,276 91,653 Thereafter 177,267 270,410 447,677 Total minimum lease payments $ 548,335 $ 430,808 $ 979,143 1 Represents the portion of future minimum lease payments related to facility leases where the Company was determined to be the accounting owner (see Note 1 of the Notes to Consolidated Financial Statements in our Annual Report on Form 10-K for the fiscal year ended September 30, 2019 for a more detailed description of the Company's accounting for leases prior to the adoption of ASC 842). These payments were recognized as reductions to the financing obligation and as interest expense and excluded the future non-cash termination of the financing obligation.

Variable Interest Entity (Table

Variable Interest Entity (Tables)	3 Months Ended
	Dec. 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) December 31, September 30, Cash and cash equivalents $ 16,433 $ 9,431 Accounts receivables, net 164,917 154,491 Inventories 195,857 185,602 Prepaid expenses and other 69,176 64,119 Property and equipment, net 31,765 30,961 Goodwill 82,309 82,309 Other intangible assets 72,814 74,429 Other long-term assets 62,526 9,169 Total assets $ 695,797 $ 610,511 Accounts payable $ 196,340 $ 165,053 Accrued expenses and other 68,903 49,191 Short-term debt 100,962 106,439 Long-term debt 62,230 60,973 Deferred income taxes 38,023 42,371 Other long-term liabilities 48,209 5,303 Total liabilities $ 514,667 $ 429,330

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	3 Months Ended
	Dec. 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 three months ended December 31, 2019 : (in thousands) Pharmaceutical Distribution Services Other Total Goodwill as of September 30, 2019 $ 4,852,775 $ 1,852,732 $ 6,705,507 Foreign currency translation — 2,257 2,257 Goodwill as of December 31, 2019 $ 4,852,775 $ 1,854,989 $ 6,707,764
Schedule of indefinite-lived intangible assets	The following is a summary of other intangible assets: December 31, 2019 September 30, 2019 (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 $ 685,366 $ — $ 685,366 $ 685,324 $ — $ 685,324 Finite-lived: Customer relationships 13 years 1,816,946 (501,862 ) 1,315,084 1,931,212 (489,471 ) 1,441,741 Trade names and other 13 years 243,667 (105,719 ) 137,948 271,521 (103,750 ) 167,771 Total other intangible assets $ 2,745,979 $ (607,581 ) $ 2,138,398 $ 2,888,057 $ (593,221 ) $ 2,294,836
Schedule of finite-lived intangible assets	The following is a summary of other intangible assets: December 31, 2019 September 30, 2019 (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 $ 685,366 $ — $ 685,366 $ 685,324 $ — $ 685,324 Finite-lived: Customer relationships 13 years 1,816,946 (501,862 ) 1,315,084 1,931,212 (489,471 ) 1,441,741 Trade names and other 13 years 243,667 (105,719 ) 137,948 271,521 (103,750 ) 167,771 Total other intangible assets $ 2,745,979 $ (607,581 ) $ 2,138,398 $ 2,888,057 $ (593,221 ) $ 2,294,836

Debt (Tables)

Debt (Tables)	3 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule of debt instruments	Debt consisted of the following: (in thousands) December 31, September 30, Revolving credit note $ — $ — Term loan due in 2020 399,819 399,778 Overdraft facility due 2021 (£30,000) 31,708 32,573 Receivables securitization facility due 2022 350,000 350,000 Multi-currency revolving credit facility due 2024 — — $500,000, 3.50% senior notes due 2021 499,037 498,908 $500,000, 3.40% senior notes due 2024 497,866 497,744 $500,000, 3.25% senior notes due 2025 496,481 496,311 $750,000, 3.45% senior notes due 2027 743,309 743,099 $500,000, 4.25% senior notes due 2045 494,568 494,514 $500,000, 4.30% senior notes due 2047 492,555 492,488 Nonrecourse debt 163,260 167,477 Total debt 4,168,603 4,172,892 Less AmerisourceBergen Corporation current portion 431,527 32,573 Less nonrecourse current portion 100,962 106,439 Total, net of current portion $ 3,636,114 $ 4,033,880

Stockholders' Equity and Earn_2

Stockholders' Equity and Earnings per Share (Tables)	3 Months Ended
	Dec. 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 (in thousands) 2019 2018 Weighted average common shares outstanding - basic 206,008 212,054 Dilutive effect of stock options and restricted stock units 1,509 1,915 Weighted average common shares outstanding - diluted 207,517 213,969

Employee Severance, Litigatio_2

Employee Severance, Litigation, and Other (Tables)	3 Months Ended
	Dec. 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 (in thousands) 2019 2018 Employee severance $ 839 $ 4,784 Litigation and opioid-related costs 24,666 14,539 Acquisition-related deal and integration costs 455 10,589 Business transformation efforts 8,460 6,979 Other restructuring initiatives 4,889 3,781 Total employee severance, litigation, and other $ 39,309 $ 40,672

Business Segment Information (T

Business Segment Information (Tables)	3 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Segment revenue	The following illustrates reportable and operating segment revenue for the periods indicated: Three months ended (in thousands) 2019 2018 Pharmaceutical Distribution Services $ 46,036,828 $ 43,744,381 Other: MWI Animal Health 1,028,318 954,584 Global Commercialization Services 818,666 716,354 Total Other 1,846,984 1,670,938 Intersegment eliminations (19,070 ) (22,867 ) Revenue $ 47,864,742 $ 45,392,452
Segment operating income	The following illustrates reportable segment operating income for the periods indicated: Three months ended (in thousands) 2019 2018 Pharmaceutical Distribution Services $ 391,694 $ 373,207 Other 104,479 98,934 Intersegment eliminations (907 ) (307 ) Total segment operating income $ 495,266 $ 471,834
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 (in thousands) 2019 2018 Total segment operating income $ 495,266 $ 471,834 Gain from antitrust litigation settlements 8,492 87,279 LIFO (expense) credit (13,281 ) 3,029 PharMEDium remediation costs (16,165 ) (20,495 ) New York State Opioid Stewardship Act — 22,000 Acquisition-related intangibles amortization (33,566 ) (45,152 ) Employee severance, litigation, and other (39,309 ) (40,672 ) Impairment of long-lived assets (138,000 ) — Operating income 263,437 477,823 Other loss 2,842 3,097 Interest expense, net 31,007 42,170 Income before income taxes $ 229,588 $ 432,556

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	Oct. 01, 2019	Dec. 31, 2019	Sep. 30, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease liabilities		$ 538,059
Right-of-use assets		499,290
Property and equipment, net		$ (1,442,383)	$ (1,770,516)
ASC 842
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease liabilities	$ 562,100
Right-of-use assets	526,281
Net of tax cumulative adjustment to retained earnings	35,100
Cumulative adjustment to retained earnings, tax	9,600
Property and equipment, net	266,000
Long-term financing obligation	$ 324,800

Leases - Lease Cost (Details)

Leases - Lease Cost (Details) $ in Thousands	3 Months Ended
	Dec. 31, 2019USD ($)
Leases [Abstract]
Operating lease cost	$ 29,935
Short-term lease cost	1,526
Variable lease cost	4,856
Total lease cost	$ 36,317

Leases - Additional Information

Leases - Additional Information (Details) $ in Millions	3 Months Ended
	Dec. 31, 2018USD ($)
Leases [Abstract]
Rental expense	$ 26.8

Leases - Summary of Balance She

Leases - Summary of Balance Sheet Information Related to Leases (Details) $ in Thousands	Dec. 31, 2019USD ($)
Right of use assets
Other assets	$ 499,290
Lease liabilities
Accrued expenses and other	97,935
Other long-term liabilities	440,124
Total lease liabilities	$ 538,059
Weighted-average remaining lease term	7 years 6 months 21 days
Weighted-average discount rate	3.81%

Leases - Other Information (Det

Leases - Other Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Oct. 01, 2019
Cash paid for amounts included in the measurement of lease liabilities
Operating lease cash payments	$ 29,100
Right-of-use assets obtained in exchange for lease liabilities
New operating leases	5,918
Leases recognized upon adoption of ASC 842	$ 499,290
ASC 842
Right-of-use assets obtained in exchange for lease liabilities
Leases recognized upon adoption of ASC 842		$ 526,281

Leases - Future Minimum Rental

Leases - Future Minimum Rental Payments Under Noncancelable Operating Leases (Details) $ in Thousands	Dec. 31, 2019USD ($)
Leases [Abstract]
2020	$ 89,675
2021	116,302
2022	111,367
2023	101,487
2024	93,647
Thereafter	453,893
Total future undiscounted lease payments	966,371
Less: Future payments for leases that have not yet commenced	(296,788)
Less: Imputed interest	(131,524)
Total lease liabilities	$ 538,059

Leases - Minimum Lease Payments

Leases - Minimum Lease Payments (Details) $ in Thousands	Dec. 31, 2019USD ($)
Operating Leases
2020	$ 94,958
2021	84,002
2022	72,224
2023	63,507
2024	56,377
Thereafter	177,267
Total minimum lease payments	548,335
Financing Obligations
2020	22,468
2021	29,790
2022	36,914
2023	35,950
2024	35,276
Thereafter	270,410
Total minimum lease payments	430,808
Operating and Financing Obligations
2020	117,426
2021	113,792
2022	109,138
2023	99,457
2024	91,653
Thereafter	447,677
Total minimum lease payments	$ 979,143

Variable Interest Entity - Fina

Variable Interest Entity - Financial Position of Variable Interest Entity (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 3,232,604	$ 3,374,194	$ 2,540,156	$ 2,492,516
Inventories	11,686,466	11,060,254
Property and equipment, net	1,442,383	1,770,516
Goodwill	6,707,764	6,705,507
Other long-term assets	773,377	269,067
TOTAL ASSETS	40,016,738	39,171,980
Long-term debt	4,168,603	4,172,892
Deferred income taxes	1,895,453	1,860,195
Other long-term liabilities	496,587	98,812
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Cash and cash equivalents	16,433	9,431
Accounts receivables, net	164,917	154,491
Inventories	195,857	185,602
Prepaid expenses and other	69,176	64,119
Property and equipment, net	31,765	30,961
Goodwill	82,309	82,309
Other intangible assets	72,814	74,429
Other long-term assets	62,526	9,169
TOTAL ASSETS	695,797	610,511
Accounts payable	196,340	165,053
Accrued expenses and other	68,903	49,191
Short-term debt	100,962	106,439
Long-term debt	62,230	60,973
Deferred income taxes	38,023	42,371
Other long-term liabilities	48,209	5,303
Total liabilities	$ 514,667	$ 429,330

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 125,200
Unrecognized tax benefits, net of federal benefit	92,700
Tax benefits that would reduce income tax expense and effective tax rate	74,500
Unrecognized tax benefits - interest and penalties	19,000
Unrecognized tax benefits - increase (decrease)	1,000
Significant change in unrecognized tax benefits is reasonably possible	$ 17,700
Effective tax rate (as a percentage)	18.70%	9.40%
Impairment of long-lived assets	$ 138,000	$ 0
Income tax benefits related to decrease in provisional tax		$ 37,000

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	3 Months Ended
	Dec. 31, 2019USD ($)
Goodwill [Roll Forward]
Goodwill	$ 6,705,507
Foreign currency translation	2,257
Goodwill	6,707,764
Operating segments | Pharmaceutical Distribution Services
Goodwill [Roll Forward]
Goodwill	4,852,775
Foreign currency translation	0
Goodwill	4,852,775
Operating segments | Other
Goodwill [Roll Forward]
Goodwill	1,852,732
Foreign currency translation	2,257
Goodwill	$ 1,854,989

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Schedule of Other Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangibles, Accumulated Amortization	$ (607,581)	$ (593,221)
Intangible Assets
Gross Carrying Amount	2,745,979	2,888,057
Net Carrying Amount	2,138,398	2,294,836
Trade names
Indefinite-lived intangibles
Indefinite-lived intangibles	$ 685,366	685,324
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in years)	13 years
Finite-lived intangibles, Gross Carrying Amount	$ 1,816,946	1,931,212
Finite-lived intangibles, Accumulated Amortization	(501,862)	(489,471)
Finite-lived intangibles, Net Carrying Amount	$ 1,315,084	1,441,741
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	$ 243,667	271,521
Finite-lived intangibles, Accumulated Amortization	(105,719)	(103,750)
Finite-lived intangibles, Net Carrying Amount	$ 137,948	$ 167,771

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Amortization expense	$ 35,300	$ 47,100
Amortization expense, fiscal year maturity
2020	126,000
2021	118,700
2022	117,000
2023	115,600
2024	114,600
Thereafter	896,500
Impairment of long-lived assets	138,000	$ 0
Pharmedium Healthcare Holdings Inc
Amortization expense, fiscal year maturity
Asset group's fair value	$ 145,000
Discount rate	17.00%
Impairment to finite-lived intangibles	$ 123,200
Impairment to property and equipment	11,600
Impairment to ROU assets	$ 3,200

Debt - Schedule of Debt Instrum

Debt - Schedule of Debt Instruments (Details)	Dec. 31, 2019GBP (£)	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)
Debt Instrument [Line Items]
Long-term debt		$ 4,168,603,000	$ 4,172,892,000
Less AmerisourceBergen Corporation current portion		431,527,000	32,573,000
Total, net of current portion		3,636,114,000	4,033,880,000
Revolving credit note
Debt Instrument [Line Items]
Maximum borrowing capacity		75,000,000
Long-term debt		0	0
Term loan due in 2020
Debt Instrument [Line Items]
Long-term debt		399,819,000	399,778,000
Overdraft facility due 2021 (£30,000)
Debt Instrument [Line Items]
Maximum borrowing capacity | £	£ 30,000,000
Long-term debt		31,708,000	32,573,000
Receivables securitization facility due 2022
Debt Instrument [Line Items]
Maximum borrowing capacity		1,450,000,000
Long-term debt		350,000,000	350,000,000
Multi-currency revolving credit facility due 2024
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		$ 499,037,000	498,908,000
$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		$ 497,866,000	497,744,000
$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		$ 496,481,000	496,311,000
$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		$ 743,309,000	743,099,000
$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		$ 494,568,000	494,514,000
$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		$ 492,555,000	492,488,000
Nonrecourse debt
Debt Instrument [Line Items]
Long-term debt		163,260,000	167,477,000
Less AmerisourceBergen Corporation current portion		$ 100,962,000	$ 106,439,000

Debt - Additional information (

Debt - Additional information (Details)	Dec. 31, 2019GBP (£)	Dec. 31, 2019GBP (£)	Dec. 31, 2019USD ($)
Multi-currency revolving credit facility due 2024
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 1,400,000,000
Facility fee	0.09%
Multi-currency revolving credit facility due 2024 | Minimum
Debt Instrument [Line Items]
Facility fee		0.05%
Multi-currency revolving credit facility due 2024 | Maximum
Debt Instrument [Line Items]
Facility fee		0.125%
Multi-currency revolving credit facility due 2024 | CDOR / LIBOR / EURIBOR / Bankers Acceptance Stamping Fee
Debt Instrument [Line Items]
Variable rate spread	0.91%
Multi-currency revolving credit facility due 2024 | CDOR / LIBOR / EURIBOR / Bankers Acceptance Stamping Fee | Minimum
Debt Instrument [Line Items]
Variable rate spread		0.70%
Multi-currency revolving credit facility due 2024 | CDOR / LIBOR / EURIBOR / Bankers Acceptance Stamping Fee | Maximum
Debt Instrument [Line Items]
Variable rate spread		1.125%
Multi-currency revolving credit facility due 2024 | Alternate base rate and Canadian prime rate | Minimum
Debt Instrument [Line Items]
Variable rate spread		0.00%
Multi-currency revolving credit facility due 2024 | Alternate base rate and Canadian prime rate | Maximum
Debt Instrument [Line Items]
Variable rate spread		0.125%
Commercial paper
Debt Instrument [Line Items]
Maximum borrowing capacity			1,400,000,000
Debt instrument, term		365 days
Amount outstanding			0
Receivables securitization facility due 2022
Debt Instrument [Line Items]
Maximum borrowing capacity			1,450,000,000
Potential increase in receivables securitization facility			250,000,000
Revolving credit note
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 75,000,000
Overdraft facility due 2021 (£30,000)
Debt Instrument [Line Items]
Maximum borrowing capacity | £	£ 30,000,000	£ 30,000,000

Stockholders' Equity and Earn_3

Stockholders' Equity and Earnings per Share - Additional Information (Details) - USD ($) shares in Millions	1 Months Ended		3 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Oct. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Repurchase of common stock			$ 129,775,000	$ 225,850,000
Antidilutive securities excluded from earnings per share computation (shares)			4.4	3.8
October 2018 Share Repurchase Program
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Authorized amount under share repurchase program					$ 1,000,000,000
Repurchase of common stock (shares)			1.6
Repurchase of common stock			$ 129,800,000
Cash settled purchases	$ 9,400,000	$ 14,800,000
Availability remaining under program	$ 331,400,000		$ 331,400,000

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
	Dec. 31, 2019	Dec. 31, 2018
Equity [Abstract]
Weighted average common shares outstanding - basic (shares)	206,008	212,054
Dilutive effect of stock options, restricted stock, and restricted stock units (shares)	1,509	1,915
Weighted average common shares outstanding - diluted (shares)	207,517	213,969

Related Party Transactions (Det

Related Party Transactions (Details) - Walgreens Boots Alliance, Inc. - Investor - USD ($) $ in Billions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2019
Related Party Transaction [Line Items]
Revenue from related party	$ 15.6	$ 15.3
Receivable from related party	$ 6.5		$ 6.1
AmerisourceBergen
Related Party Transaction [Line Items]
Ownership percentage (more than)	10.00%

Employee Severance, Litigatio_3

Employee Severance, Litigation, and Other (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Employee severance	$ 839	$ 4,784
Litigation and opioid-related costs	24,666	14,539
Total employee severance, litigation, and other	39,309	40,672
Acquisition-related and integration costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs	455	10,589
Business transformation efforts
Restructuring Cost and Reserve [Line Items]
Restructuring costs	8,460	6,979
Other restructuring initiatives
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 4,889	$ 3,781

Legal Matters and Contingenci_2

Legal Matters and Contingencies (Details) - USD ($)	Oct. 21, 2019	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Sep. 30, 2019	Jul. 01, 2018
Loss Contingencies [Line Items]
Litigation settlement			$ 24,666,000	$ 14,539,000
Annual fund amount total							$ 100,000,000
Estimated liability under the New York Opioid Stewardship Act				$ (22,000,000)	$ 22,000,000
Settlement with Ohio Counties
Loss Contingencies [Line Items]
Payment pursuant to settlement		$ 66,700,000
Litigation settlement						$ 66,700,000
MDL and Other Related State Court Litigation
Loss Contingencies [Line Items]
Aggregate legal settlement (up to)	$ 18,000,000,000
Legal settlement term (in years)	18 years
Company's portion of aggregate legal settlement	31.00%
Program period (in years)	10 years

Litigation Settlements (Details

Litigation Settlements (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Gain from antitrust litigation settlements	$ 8.5	$ 87.3

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2019	Sep. 30, 2019
Reported Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 3,636.1	$ 4,033.9
Estimate of Fair Value Measurement | Level 2 inputs
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	3,756.6	4,158.4
Money market | Estimate of Fair Value Measurement | Level 1 inputs
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 1,006	$ 1,552

Business Segment Information -

Business Segment Information - Segment Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 47,864,742	$ 45,392,452
Intersegment eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	(19,070)	(22,867)
Pharmaceutical Distribution Services | Operating segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	46,036,828	43,744,381
Other | Operating segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	1,846,984	1,670,938
MWI Animal Health | Other | Operating segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	1,028,318	954,584
Global Commercialization Services | Other | Operating segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 818,666	$ 716,354

Business Segment Information _2

Business Segment Information - Segment Operating Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Total segment operating income	$ 263,437	$ 477,823
Operating segments
Segment Reporting Information [Line Items]
Total segment operating income	495,266	471,834
Intersegment eliminations
Segment Reporting Information [Line Items]
Total segment operating income	(907)	(307)
Pharmaceutical Distribution Services | Operating segments
Segment Reporting Information [Line Items]
Total segment operating income	391,694	373,207
Other | Operating segments
Segment Reporting Information [Line Items]
Total segment operating income	$ 104,479	$ 98,934

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
	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income	$ 263,437	$ 477,823
Gain from antitrust litigation settlements	8,500	87,300
LIFO (expense) credit	(13,281)	3,029
Employee severance, litigation, and other	(39,309)	(40,672)
Impairment of long-lived assets	(138,000)	0
Other loss	2,842	3,097
Interest expense, net	31,007	42,170
Income before income taxes	229,588	432,556
Operating segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income	495,266	471,834
Segment reconciling items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Gain from antitrust litigation settlements	8,492	87,279
LIFO (expense) credit	(13,281)	3,029
PharMEDium remediation costs	(16,165)	(20,495)
New York State Opioid Stewardship Act	0	22,000
Acquisition-related intangibles amortization	(33,566)	(45,152)
Employee severance, litigation, and other	(39,309)	(40,672)
Impairment of long-lived assets	$ (138,000)	$ 0

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended			12 Months Ended
	Jan. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2020
Subsequent Event [Line Items]
Cash dividends declared per share of common stock (usd per share)			$ 0.40	$ 0.40
Impairment of tangible assets			$ 138,000	$ 0
Cash tax benefit			(43,020)	$ (40,803)
Subsequent Event
Subsequent Event [Line Items]
Increase in quarterly dividend paid on common stock (as a percentage)	5.00%
Cash dividends declared per share of common stock (usd per share)	$ 0.42
Forecast | Minimum
Subsequent Event [Line Items]
Cash tax benefit					$ 500,000
Forecast | Maximum
Subsequent Event [Line Items]
Cash tax benefit					$ 600,000
Pharmedium Healthcare Holdings Inc
Subsequent Event [Line Items]
Impairment of tangible assets			138,000
Pharmedium Healthcare Holdings Inc | Minimum
Subsequent Event [Line Items]
Incurred costs with exit of PharMEDium			80,000
Pharmedium Healthcare Holdings Inc | Maximum
Subsequent Event [Line Items]
Incurred costs with exit of PharMEDium			$ 100,000
Pharmedium Healthcare Holdings Inc | Forecast
Subsequent Event [Line Items]
Tangible Asset Impairment Charges		$ 55,000
Impairment of Intangible assets		$ 185,000

Uncategorized Items - a10-qxq12

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] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(1,482,000)
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 2016-02 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	35,138,000
Accounting Standards Update 2016-02 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	35,138,000
Accounting Standards Update 2016-02 [Member] | Noncontrolling Interest [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 0