Cencora (COR) 10-Q 4 May 17 2017 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Mar. 31, 2017	Apr. 30, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	AMERISOURCEBERGEN CORP
Entity Central Index Key	1,140,859
Document Type	10-Q
Document Period End Date	Mar. 31, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--09-30
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		218,356,117
Trading Symbol	abc

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2017	Sep. 30, 2016
Current assets:
Cash and cash equivalents	$ 2,404,433	$ 2,741,832
Accounts receivable, less allowances for returns and doubtful accounts: $901,755 at March 31, 2017 and $905,345 at September 30, 2016	9,583,520	9,175,876
Merchandise inventories	11,335,816	10,723,920
Prepaid expenses and other	170,152	210,219
Total current assets	23,493,921	22,851,847
Property and equipment, at cost:
Land	40,279	40,290
Buildings and improvements	975,405	859,148
Machinery, equipment, and other	1,880,048	1,717,298
Total property and equipment	2,895,732	2,616,736
Less accumulated depreciation	(1,193,672)	(1,086,054)
Property and equipment, net	1,702,060	1,530,682
Goodwill	5,987,729	5,991,497
Other intangible assets	2,888,920	2,967,849
Other assets	324,383	295,626
TOTAL ASSETS	34,397,013	33,637,501
Current liabilities:
Accounts payable	24,276,019	23,926,320
Accrued expenses and other	639,560	743,839
Short-term debt	615,847	610,210
Total current liabilities	25,531,426	25,280,369
Long-term debt	3,478,214	3,576,493
Long-term financing obligation	361,384	275,991
Deferred income taxes	2,332,051	2,214,774
Other liabilities	164,646	160,470
Stockholders’ equity:
Common stock, $0.01 par value - authorized, issued, and outstanding: 600,000,000 shares, 279,646,620 shares, and 218,314,621 shares at March 31, 2017, respectively, and 600,000,000 shares, 277,753,762 shares, and 220,050,502 shares at September 30, 2016, respectively	2,796	2,778
Additional paid-in capital	4,455,260	4,333,001
Retained earnings	2,849,630	2,303,941
Accumulated other comprehensive loss	(123,490)	(114,308)
Treasury stock, at cost: 61,331,999 shares at March 31, 2017 and 57,703,260 shares at September 30, 2016	(4,654,904)	(4,396,008)
Total stockholders’ equity	2,529,292	2,129,404
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 34,397,013	$ 33,637,501

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2017	Sep. 30, 2016
Statement of Financial Position [Abstract]
Allowances for returns and doubtful accounts	$ 901,755	$ 905,345
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)	279,646,620	277,753,762
Common stock, outstanding (shares)	218,314,621	220,050,502
Treasury stock (shares)	61,331,999	57,703,260

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended			6 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Revenue	$ 37,147,402		$ 35,698,357	$ 75,316,667	$ 72,407,403
Cost of goods sold	35,890,975		34,623,026	73,022,560	70,367,195
Gross profit	1,256,427		1,075,331	2,294,107	2,040,208
Operating expenses:
Distribution, selling, and administrative	521,843		519,466	1,042,390	1,044,543
Depreciation	57,751		52,995	113,605	103,861
Amortization	39,918		39,841	80,144	71,937
Warrants	0		(503,946)	0	(36,571)
Employee severance, litigation, and other	11,934		17,617	33,000	36,485
Pension settlement	0		(1,124)	0	47,607
Operating income	624,981		950,482	1,024,968	772,346
Other income	(5,233)		(756)	(5,356)	(1,066)
Interest expense, net	37,299		35,966	74,271	69,707
Income before income taxes	592,915		915,272	956,053	703,705
Income tax expense (benefit)	181,442		311,822	297,334	(229,384)
Net income	$ 411,473		$ 603,450	$ 658,719	$ 933,089
Earnings per share:
Basic (usd per share)	$ 1.89		$ 2.90	$ 3.02	$ 4.51
Diluted (usd per share)	$ 1.86		$ 2.68	$ 2.97	$ 4.13
Weighted average common shares outstanding:
Basic (shares)	217,650		207,858	218,166	207,017
Diluted (shares)	221,221		225,450	221,611	226,082
Cash dividends declared per share of common stock (usd per share)	$ 0.365	$ 0.34	$ 0.34	$ 0.73	$ 0.68

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 411,473	$ 603,450	$ 658,719	$ 933,089
Other comprehensive income (loss)
Net change in foreign currency translation adjustments	18,545	13,911	(9,012)	3,477
Pension plan adjustment, net of tax of $19,054	0	0	0	31,538
Other	(184)	(281)	(170)	(866)
Total other comprehensive income (loss)	18,361	13,630	(9,182)	34,149
Total comprehensive income	$ 429,834	$ 617,080	$ 649,537	$ 967,238

CONSOLIDATED STATEMENTS OF COM6

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) $ in Thousands	6 Months Ended
	Mar. 31, 2016USD ($)
Statement of Comprehensive Income [Abstract]
Pension plan adjustments, tax	$ 19,054

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
OPERATING ACTIVITIES
Net income	$ 658,719	$ 933,089
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, including amounts charged to cost of goods sold	127,184	112,844
Amortization, including amounts charged to interest expense	85,194	75,385
Provision for doubtful accounts	5,384	8,065
Provision (benefit) for deferred income taxes	159,397	(292,981)
Warrants income	0	(36,571)
Share-based compensation	41,250	39,787
LIFO (credit) expense	(58,196)	193,941
Pension settlement	0	47,607
Other	(6,809)	(193)
Changes in operating assets and liabilities, excluding the effects of acquisitions and divestitures:
Accounts receivable	(417,705)	(472,074)
Merchandise inventories	(556,057)	(1,047,018)
Prepaid expenses and other assets	26,591	17,642
Accounts payable	350,960	2,070,716
Accrued expenses, income taxes, and other liabilities	(47,528)	(18,219)
NET CASH PROVIDED BY OPERATING ACTIVITIES	368,384	1,632,020
INVESTING ACTIVITIES
Capital expenditures	(262,700)	(180,012)
Cost of acquired companies, net of cash acquired	(2,403)	(2,731,356)
Proceeds from sales of investment securities available-for-sale	36,128	88,829
Purchases of investment securities available-for-sale	(48,635)	(41,136)
Other	8,136	(10,878)
NET CASH USED IN INVESTING ACTIVITIES	(269,474)	(2,874,553)
FINANCING ACTIVITIES
Term loan borrowings	0	1,000,000
Term loan repayments	(100,000)	(25,000)
Borrowings under revolving and securitization credit facilities	6,711,081	8,237,792
Repayments under revolving and securitization credit facilities	(6,705,964)	(8,217,849)
Purchases of common stock	(229,928)	(436,804)
Exercises of warrants	0	1,168,891
Exercises of stock options	61,383	37,285
Cash dividends on common stock	(160,093)	(141,829)
Tax withholdings related to restricted share vesting	(8,968)	(18,233)
Other	(3,820)	(3,875)
NET CASH (USED IN) PROVIDED BY FINANCING ACTIVITIES	(436,309)	1,600,378
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(337,399)	357,845
Cash and cash equivalents at beginning of period	2,741,832	2,167,442
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 2,404,433	$ 2,525,287

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Mar. 31, 2017
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 wholly-owned subsidiaries (the "Company") as of the dates and for the periods indicated. All intercompany accounts and transactions have been eliminated in consolidation. The accompanying unaudited consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles ("GAAP") for interim financial information, the instructions to Form 10-Q, and Rule 10-01 of Regulation S-X. In the opinion of management, all adjustments (consisting only of normal recurring accruals, except as otherwise disclosed herein) considered necessary to present fairly the financial position as of March 31, 2017 and the results of operations and cash flows for the interim periods ended March 31, 2017 and 2016 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, 2016 . 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. Certain reclassifications have been made to prior-period amounts in order to conform to the current year presentation. Recently Adopted Accounting Pronouncements In April 2015, the FASB issued ASU No. 2015-03, "Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs" ("ASU 2015-03"). ASU 2015-03 specifies that debt issuance costs related to a debt liability shall be reported on the balance sheet as a direct reduction from the face amount of the debt liability. In August 2015, the FASB issued ASU No. 2015-15, "Interest - Imputation of Interest (Subtopic 835-30): Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements" ("ASU 2015-15"). ASU 2015-15 specifies that debt issuance costs related to line-of-credit arrangements may be presented as an asset on the balance sheet and subsequently amortized ratably over the term of the line-of-credit arrangement, regardless of whether there are any outstanding borrowings on the line-of-credit arrangement. As of October 1, 2016, the Company adopted ASU 2015-03 and ASU 2015-15, which resulted in the reclassification of $18.7 million of debt issuance costs from Other Assets to Short-Term Debt of $0.9 million and to Long-Term Debt of $17.8 million on the Company's September 30, 2016 Consolidated Balance Sheet. The adoption had no impact on the Company’s results of operations or cash flows. In March 2016, the FASB issued ASU No. 2016-09, "Compensation — Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting" ("ASU 2016-09"). ASU 2016-09 requires all income tax effects of awards to be recognized in the income statement when the awards vest or are settled. It also allows an employer to repurchase more of an employee's shares than it may currently for tax withholding purposes without triggering liability accounting and to make a policy election to account for forfeitures as they occur. ASU 2016-09 is effective for annual reporting periods beginning after December 15, 2016 and interim periods within those fiscal years. Entities are permitted to adopt the standard early in any interim or annual period. During the quarter ended December 31, 2016, the Company early adopted ASU 2016-09, which resulted in a cumulative adjustment to retained earnings and established a deferred tax asset as of October 1, 2016 of $47.1 million for previously unrecognized tax benefits. The Company elected to adopt the Statement of Cash Flows presentation of the excess tax benefits prospectively. During the three and six months ended March 31, 2017 , the Company recognized tax benefits of $19.8 million and $24.0 million , respectively, in Income Tax Expense on the Company's Consolidated Statement of Operations. The tax benefits recognized in the three and six months ended March 31, 2017 are not necessarily indicative of amounts that may arise in future periods. Recently Issued Accounting Pronouncements Not Yet Adopted In May 2014, the FASB issued ASU No. 2014-09, "Revenue from Contracts with Customers (Topic 606)" ("ASU 2014-09"). ASU 2014-09 supersedes the revenue recognition requirements in Accounting Standards Codification 605 — "Revenue Recognition" and most industry-specific guidance throughout the Codification. ASU 2014-09 outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers. The standard's core principle is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 was originally scheduled to be effective for annual reporting periods beginning after December 15, 2016, including interim periods within those reporting periods. In July 2015, the Financial Accounting Standards Board deferred the effective date of ASU 2014-09 by one year. In March 2016, the FASB issued ASU No. 2016-08, "Revenue from Contracts with Customers (Topic 606) — Principal versus Agent Considerations" ("ASU 2016-08"), which clarifies the implementation guidance for principal versus agent considerations in ASU 2014-09. In April 2016, the FASB issued ASU No. 2016-10, "Revenue from Contracts with Customers (Topic 606) — Identifying Performance Obligations and Licensing" ("ASU 2016-10"), which amends the guidance in ASU 2014-09 related to identifying performance obligations and accounting for licenses of intellectual property. The Company must adopt ASU 2016-08 and ASU 2016-10 with ASU 2014-09. Entities are permitted to adopt the standards as early as the original public entity effective date of ASU 2014-09, and either full or modified retrospective application is required. The Company has not yet selected an adoption date or a transition method for ASU 2014-09, 2016-08, and 2016-10 and is currently evaluating the impact of adopting this new accounting guidance and, therefore, cannot reasonably estimate the impact that the adoption of the above standards will have on its financial statements. In February 2016, the FASB issued ASU No. 2016-02, "Leases (Topic 842)" ("ASU 2016-02"). ASU 2016-02 aims to increase transparency and comparability across organizations by requiring lease assets and lease liabilities to be recognized on the balance sheet as well as key information to be disclosed regarding lease arrangements. ASU 2016-02 is effective for annual reporting periods beginning after December 15, 2018, and interim periods within those fiscal years. Entities are permitted to adopt the standard early, and a modified retrospective application is required. The Company is currently evaluating the impact of adopting this new accounting guidance and, therefore, cannot reasonably estimate the impact that the adoption of this standard will have on its financial statements. In August 2016, the FASB issued ASU No. 2016-15, "Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments" ("ASU 2016-15"). ASU 2016-15 aims to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. ASU 2016-15 is effective for annual reporting periods beginning after December 15, 2017 and interim periods within those fiscal years. Entities are permitted to adopt the standard early in any interim or annual period, and a retrospective application is required. The Company is currently evaluating the impact of adopting this new accounting guidance and, therefore, cannot reasonably estimate the impact that the adoption of this standard will have on its financial statements. In January 2017, the FASB issued ASU No. 2017-04, "Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment" ("ASU 2017-04"). ASU 2017-04 removes Step 2 of the goodwill impairment test, which requires a hypothetical purchase price allocation. A goodwill impairment will now be the amount by which a reporting unit’s carrying value exceeds its fair value. ASU 2017-04 is effective for annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Entities are permitted to adopt the standard early for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company does not expect that the adoption of this standard will impact the Company's results of operations, cash flows, or financial position. As of March 31, 2017 , 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.

Revision of Previously Issued F

Revision of Previously Issued Financial Statements	6 Months Ended
	Mar. 31, 2017
Accounting Changes and Error Corrections [Abstract]
Revision of Previously Issued Financial Statements	Revision of Previously Issued Financial Statements In fiscal 2016, the Company engaged in a review of the accounting treatment of leases. As part of this review, the Company assessed its historical application of Accounting Standards Codification 840, "Leases," ("ASC 840") regarding lessee involvement in the construction of leased assets and identified corrections to be made in its accounting for these leases. In a number of its leases, the Company made payments for certain structural components included in the lessor's construction of the leased assets, which resulted in the Company being deemed the owner of the leased assets for accounting purposes. As a result, regardless of the significance of the payments, ASC 840 defines those payments as automatic indicators of ownership and requires the Company to capitalize the lessor's total project cost on the balance sheet with a corresponding financing obligation. In these situations, the Company had not historically accounted for the total project costs of the lessor as owned assets. Additionally, upon completion of the lessor's project, the Company must perform a sale-leaseback analysis pursuant to ASC 840 to determine if it can derecognize these assets and the related financing obligations from its consolidated balance sheet. In a substantial number of its leases, due to many of the same factors that require it to account for the total project costs as owned assets during the construction period (for example, the Company funding a portion of the construction costs), it was deemed to have "continuing involvement," which precluded the Company from derecognizing these leased assets when construction was complete. In such cases, the leased assets and the related financing obligations remain on the consolidated balance sheet and are amortized over the life of the assets and the lease term, respectively. The Company revised the prior year's financial statements. The corrections had no impact on diluted earnings per share in the three and six months ended March 31, 2016. The Company no longer reports rent expense for the leased facilities that are owned for accounting purposes. Instead, rental payments under the leases are recognized as a reduction of the financing obligation and as interest expense. Additionally, depreciation expense is recorded as construction assets are depreciated over their useful lives. These corrections had no impact on the net increase in cash and cash equivalents in the six months ended March 31, 2016 . The following illustrates the impact the aforementioned adjustments had on the Company's previously issued financial statements: CONSOLIDATED STATEMENT OF OPERATIONS Three months ended March 31, 2016 (in thousands, except per share data) As Previously Reported Adjustments As Revised Revenue $ 35,698,357 $ — $ 35,698,357 Cost of goods sold 34,623,026 — 34,623,026 Gross profit 1,075,331 — 1,075,331 Operating expenses: Distribution, selling, and administrative 522,760 (3,294 ) 519,466 Depreciation 51,471 1,524 52,995 Amortization 39,841 — 39,841 Warrants (503,946 ) — (503,946 ) Employee severance, litigation, and other 17,617 — 17,617 Pension settlement (1,124 ) — (1,124 ) Operating income 948,712 1,770 950,482 Other income (756 ) — (756 ) Interest expense, net 33,113 2,853 35,966 Income before income taxes 916,355 (1,083 ) 915,272 Income tax expense 312,220 (398 ) 311,822 Net income $ 604,135 $ (685 ) $ 603,450 Earnings per share: Basic $ 2.91 $ (0.01 ) $ 2.90 Diluted $ 2.68 $ — $ 2.68 Weighted average common shares outstanding: Basic 207,858 — 207,858 Diluted 225,450 — 225,450 CONSOLIDATED STATEMENT OF OPERATIONS Six months ended March 31, 2016 (in thousands, except per share data) As Previously Reported Adjustments As Revised Revenue $ 72,407,403 $ — $ 72,407,403 Cost of goods sold 70,367,195 — 70,367,195 Gross profit 2,040,208 — 2,040,208 Operating expenses: Distribution, selling, and administrative 1,051,056 (6,513 ) 1,044,543 Depreciation 100,813 3,048 103,861 Amortization 71,937 — 71,937 Warrants (36,571 ) — (36,571 ) Employee severance, litigation, and other 36,485 — 36,485 Pension settlement 47,607 — 47,607 Operating income 768,881 3,465 772,346 Other income (1,066 ) — (1,066 ) Interest expense, net 63,992 5,715 69,707 Income before income taxes 705,955 (2,250 ) 703,705 Income tax benefit (228,557 ) (827 ) (229,384 ) Net income $ 934,512 $ (1,423 ) $ 933,089 Earnings per share: Basic $ 4.51 $ — $ 4.51 Diluted $ 4.13 $ — $ 4.13 Weighted average common shares outstanding: Basic 207,017 — 207,017 Diluted 226,082 — 226,082 CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME Three months ended March 31, 2016 (in thousands) As Previously Reported Adjustments As Revised Net income $ 604,135 $ (685 ) $ 603,450 Other comprehensive income: Net change in foreign currency translation adjustments 13,911 — 13,911 Other (281 ) — (281 ) Total other comprehensive income 13,630 — 13,630 Total comprehensive income $ 617,765 $ (685 ) $ 617,080 Six months ended March 31, 2016 (in thousands) As Previously Reported Adjustments As Revised Net income $ 934,512 $ (1,423 ) $ 933,089 Other comprehensive income: Net change in foreign currency translation adjustments 3,477 — 3,477 Pension plan adjustment, net of tax of $19,054 31,538 — 31,538 Other (866 ) — (866 ) Total other comprehensive income 34,149 — 34,149 Total comprehensive income $ 968,661 $ (1,423 ) $ 967,238 CONSOLIDATED STATEMENT OF CASH FLOWS Six months ended March 31, 2016 (in thousands) As Previously Reported Adjustments As Revised OPERATING ACTIVITIES Net income $ 934,512 $ (1,423 ) $ 933,089 Adjustments to reconcile net income to net cash provided by operating activities: Depreciation, including amounts charged to cost of goods sold 109,796 3,048 112,844 Amortization, including amounts charged to interest expense 75,144 241 75,385 Provision for doubtful accounts 8,065 — 8,065 Benefit for deferred income taxes (292,154 ) (827 ) (292,981 ) Warrants income (36,571 ) — (36,571 ) Share-based compensation 39,787 — 39,787 LIFO expense 1 193,941 — 193,941 Pension settlement 47,607 — 47,607 Other (193 ) — (193 ) Changes in operating assets and liabilities, excluding the effects of acquisitions: Accounts receivable (472,074 ) — (472,074 ) Merchandise inventories 1 (1,047,018 ) — (1,047,018 ) Prepaid expenses and other assets 17,642 — 17,642 Accounts payable 2,070,716 — 2,070,716 Accrued expenses, income taxes, and other liabilities (18,614 ) 395 (18,219 ) NET CASH PROVIDED BY OPERATING ACTIVITIES 1,630,586 1,434 1,632,020 INVESTING ACTIVITIES Capital expenditures (180,012 ) — (180,012 ) Cost of acquired companies, net of cash acquired (2,731,356 ) — (2,731,356 ) Proceeds from sales of investment securities available-for-sale 88,829 — 88,829 Purchases of investment securities available-for-sale (41,136 ) — (41,136 ) Other (10,878 ) — (10,878 ) NET CASH USED IN INVESTING ACTIVITIES (2,874,553 ) — (2,874,553 ) FINANCING ACTIVITIES Term loan borrowings 1,000,000 — 1,000,000 Term loan repayments (25,000 ) — (25,000 ) Borrowings under revolving and securitization credit facilities 8,237,792 — 8,237,792 Repayments under revolving and securitization credit facilities (8,217,849 ) — (8,217,849 ) Purchases of common stock (436,804 ) — (436,804 ) Exercises of warrants 1,168,891 — 1,168,891 Exercises of stock options 37,285 — 37,285 Cash dividends on common stock (141,829 ) — (141,829 ) Tax withholdings related to restricted share vesting (18,233 ) — (18,233 ) Other (2,441 ) (1,434 ) (3,875 ) NET CASH PROVIDED BY FINANCING ACTIVITIES 1,601,812 (1,434 ) 1,600,378 INCREASE IN CASH AND CASH EQUIVALENTS 357,845 — 357,845 Cash and cash equivalents at beginning of period 2,167,442 — 2,167,442 CASH AND CASH EQUIVALENTS AT END OF PERIOD $ 2,525,287 $ — $ 2,525,287 1 Amounts as previously reported have been revised to report LIFO Expense separately from the change in Merchandise Inventories.

Income Taxes

Income Taxes	6 Months Ended
	Mar. 31, 2017
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 March 31, 2017 , 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 $99.2 million ( $71.1 million , net of federal benefit). If recognized, these tax benefits would reduce income tax expense and the effective tax rate. Included in this amount is $14.0 million of interest and penalties, which the Company records in income tax expense. During the six months ended March 31, 2017 , unrecognized tax benefits increased by $11.0 million . Over the next 12 months, it is reasonably possible that state tax audit resolutions and the expiration of statutes of limitations could result in a reduction of unrecognized tax benefits by approximately $4.7 million . The Company's effective tax rates were 30.6% and 31.1% in the three and six months ended March 31, 2017, respectively. The Company's effective tax rates were 34.1% and (32.6)% in the three and six months ended March 31, 2016, respectively. The effective tax rates in the three and six months ended March 31, 2017 were favorably impacted due to growth of the Company's international businesses and also benefited from stock option exercises and restricted stock vesting. Prior to fiscal 2017, tax benefits resulting from share-based compensation were recorded as adjustments to Additional Paid-In Capital within Stockholders' Equity. The effective tax rate in the six months ended March 31, 2016 benefited from the receipt of an Internal Revenue Service private letter ruling that entitled the Company to an income tax deduction equal to the fair value of the Warrants on the dates of exercise.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	6 Months Ended
	Mar. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Following is a summary of the changes in the carrying value of goodwill, by reportable segment, for the six months ended March 31, 2017 : (in thousands) Pharmaceutical Distribution Services Other Total Goodwill at September 30, 2016 $ 4,264,485 $ 1,727,012 $ 5,991,497 Goodwill recognized in connection with acquisition — 1,044 1,044 Goodwill disposed in connection with divestiture — (3,564 ) (3,564 ) Foreign currency translation — (1,248 ) (1,248 ) Goodwill at March 31, 2017 $ 4,264,485 $ 1,723,244 $ 5,987,729 Following is a summary of other intangible assets: March 31, 2017 September 30, 2016 (in thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Indefinite-lived trade names $ 684,965 $ — $ 684,965 $ 684,991 $ — $ 684,991 Finite-lived: Customer relationships 2,320,994 (340,662 ) 1,980,332 2,322,404 (273,638 ) 2,048,766 Trade names and other 308,473 (84,850 ) 223,623 307,234 (73,142 ) 234,092 Total other intangible assets $ 3,314,432 $ (425,512 ) $ 2,888,920 $ 3,314,629 $ (346,780 ) $ 2,967,849 Amortization expense for finite-lived intangible assets was $40.2 million and $39.8 million in the three months ended March 31, 2017 and 2016 , respectively. Amortization expense for finite-lived intangible assets was $80.4 million and $71.9 million in the six months ended March 31, 2017 and 2016 , respectively. Amortization expense for finite-lived intangible assets is estimated to be $160.2 million in fiscal 2017 , $158.1 million in fiscal 2018 , $153.4 million in fiscal 2019 , $149.2 million in fiscal 2020 , $148.3 million in fiscal 2021 , and $1,515.2 million thereafter.

Debt

Debt	6 Months Ended
	Mar. 31, 2017
Debt Disclosure [Abstract]
Debt	Debt Debt consisted of the following: (in thousands) March 31, September 30, Revolving credit note $ — $ — Receivables securitization facility due 2019 500,000 500,000 Term loans due in 2020 597,458 697,055 Multi-currency revolving credit facility due 2021 — — Overdraft facility due 2021 16,053 11,275 $600,000, 1.15% senior notes due 2017 599,794 598,935 $400,000, 4.875% senior notes due 2019 398,034 397,669 $500,000, 3.50% senior notes due 2021 497,619 497,361 $500,000, 3.40% senior notes due 2024 496,521 496,276 $500,000, 3.25% senior notes due 2025 494,608 494,266 $500,000, 4.25% senior notes due 2045 493,974 493,866 Total debt 4,094,061 4,186,703 Less current portion 615,847 610,210 Total, net of current portion $ 3,478,214 $ 3,576,493 The Company has a $1.4 billion multi-currency senior unsecured revolving credit facility ("Multi-Currency Revolving Credit Facility"), which expires in November 2021 , 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 110 basis points over CDOR/LIBOR/EURIBOR/Bankers Acceptance Stamping Fee, as applicable ( 91 basis points over CDOR/LIBOR/EURIBOR/Bankers Acceptance Stamping Fee at March 31, 2017 ) and from 0 basis points to 10 basis points over the alternate base rate and Canadian prime rate , as applicable. The Company pays facility fees to maintain the availability under the Multi-Currency Revolving Credit Facility at specified rates based on its debt rating, ranging from 5 basis points to 15 basis points , annually, of the total commitment ( 9 basis points at March 31, 2017 ). The Company may choose to repay or reduce its commitments under the Multi-Currency Revolving Credit Facility at any time. The Multi-Currency Revolving Credit Facility contains covenants, including compliance with a financial leverage ratio test, as well as others that impose limitations on, among other things, indebtedness of subsidiaries and asset sales, with which the Company was compliant as of March 31, 2017 . The Company has a commercial paper program whereby it may from time to time issue short-term promissory notes in an aggregate amount of up to $1.4 billion at any one time. Amounts available under the program may be borrowed, repaid, and re-borrowed from time to time. The maturities on the notes will vary, but may not exceed 365 days from the date of issuance. The notes will bear interest, if interest bearing, or will be sold at a discount from their face amounts. The commercial paper program does not increase the Company’s borrowing capacity as it is fully backed by the Company’s Multi-Currency Revolving Credit Facility. There were no borrowings outstanding under the commercial paper program as of March 31, 2017 . The Company has a $1,450 million receivables securitization facility ("Receivables Securitization Facility"), which expires in November 2019 . The Company has available to it an accordion feature whereby the commitment on the Receivables Securitization Facility may be increased by up to $250 million , subject to lender approval, for seasonal needs during the December and March quarters. Interest rates are based on prevailing market rates for short-term commercial paper or LIBOR, plus a program fee. The Company pays a customary unused fee at prevailing market rates, annually, to maintain the availability under the Receivables Securitization Facility. The Receivables Securitization Facility contains similar covenants to the Multi-Currency Revolving Credit Facility, with which the Company was compliant as of March 31, 2017 . 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 Animal Health ("MWI") business. In February 2015, the Company entered into a $1.0 billion variable-rate term loan ("February 2015 Term Loan"), which matures in 2020. Through March 31, 2017 , the Company elected to make principal payments, prior to the scheduled repayment dates, of $725 million on the February 2015 Term Loan, and as a result, the Company’s next required principal payment is due upon maturity. The February 2015 Term Loan bears interest at a rate equal either to a base rate plus a margin, or LIBOR, plus a margin. The margin is based on the public debt ratings of the Company and ranges from 75 basis points to 125 basis points over LIBOR ( 100 basis points at March 31, 2017 ) and 0 basis points to 25 basis points over a base rate. The February 2015 Term Loan contains similar covenants to the Multi-Currency Revolving Credit Facility, with which the Company was compliant as of March 31, 2017 . In November 2015, the Company entered into a $1.0 billion variable-rate term loan ("November 2015 Term Loan"), which matures in 2020. Through March 31, 2017 , the Company elected to make principal payments, prior to the scheduled repayment date, of $650 million on the November 2015 Term Loan, and as a result, the Company's next required principal payment is due upon maturity. The November 2015 Term Loan bears interest at a rate equal either to a base rate, plus a margin, or LIBOR, plus a margin. The margin is based on the public debt ratings of the Company and ranges from 75 basis points to 125 basis points over LIBOR ( 100 basis points at March 31, 2017 ) and 0 basis points to 25 basis points over a base rate. The November 2015 Term Loan contains similar covenants to the Multi-Currency Revolving Credit Facility, with which the Company was compliant as of March 31, 2017 .

Stockholders' Equity and Earnin

Stockholders' Equity and Earnings per Share	6 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Stockholders' Equity and Earnings per Share	Stockholders’ Equity and Earnings per Share In November 2016 , the Company’s board of directors increased the quarterly cash dividend by 7% from $0.340 per share to $0.365 per share. In May 2016, the Company's board of directors authorized a share repurchase program that, together with availability remaining under the previously approved August 2013 share repurchase program, permitted the Company to purchase up to $750 million of its outstanding shares of common stock, subject to market conditions. During the three months ended December 31, 2016, the Company purchased 2.1 million shares of its common stock (includes 0.5 million shares of common stock received as part of the settlement of the September 2016 accelerated share repurchase transaction) for a total of $118.8 million to complete its authorization under this program. In November 2016, the Company's board of directors authorized a new share repurchase program allowing the Company to purchase up to $1.0 billion of its outstanding shares of common stock, subject to market conditions. During the six months ended March 31, 2017 , the Company purchased 1.4 million shares of its common stock for a total of $111.1 million . As of March 31, 2017 , the Company had $888.9 million of availability remaining under the November 2016 share repurchase program. Basic earnings per share is computed on the basis of the weighted average number of shares of common stock outstanding during the periods presented. Diluted earnings per share is computed on the basis of the weighted average number of shares of common stock outstanding during the periods presented, plus the dilutive effect of stock options, restricted stock, restricted stock units, and Warrants. Three months ended Six months ended (in thousands) 2017 2016 2017 2016 Weighted average common shares outstanding - basic 217,650 207,858 218,166 207,017 Dilutive effect of stock options, restricted stock, and restricted stock units 3,571 3,421 3,445 3,639 Dilutive effect of Warrants — 14,171 — 15,426 Weighted average common shares outstanding - diluted 221,221 225,450 221,611 226,082 The potentially dilutive stock options, restricted stock, and restricted stock units that were antidilutive for the three and six months ended March 31, 2017 were 3.8 million and 4.6 million , respectively. The potentially dilutive stock options, restricted stock, restricted stock units, and Warrants that were antidilutive for the three and six months ended March 31, 2016 were 2.3 million and 1.9 million , respectively.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Mar. 31, 2017
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 branded and generic pharmaceutical products to WBA, and an agreement that provides the Company the ability to access generics and related pharmaceutical products through a global sourcing arrangement with Walgreens Boots Alliance Development GmbH. Both of these agreements expire in 2026. Revenue from the various agreements and arrangements with WBA was $11.0 billion and $22.2 billion in the three and six months ended March 31, 2017 , respectively. Revenue from the various agreements and arrangements with WBA was $10.7 billion and $21.7 billion in the three and six months ended March 31, 2016 , respectively. The Company’s receivable from WBA (after incentives owed to it) was $4.6 billion and $4.0 billion at March 31, 2017 and September 30, 2016 , respectively.

Legal Matters and Contingencies

Legal Matters and Contingencies	6 Months Ended
	Mar. 31, 2017
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, and government investigations, including antitrust, commercial, environmental, product liability, intellectual property, regulatory, employment discrimination, and other matters. Significant damages or penalties may be sought from the Company in some matters, and some matters may require years for the Company to resolve. The Company records a reserve for these matters when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. With respect to the specific legal proceedings and claims described below, 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 for that period or on the Company's financial condition. Government Enforcement and Related Litigation Matters The Company is involved in government investigations and litigation arising from the marketing, promotion, sale, and dispensing of pharmaceutical products in the United States. Some of these investigations originate through what are known as qui tam complaints of the Federal False Claims Act. The qui tam provisions of the Federal Civil False Claims Act and various state and local civil False Claims Acts permit a private person, known as a "relator" or whistleblower, to file civil actions under these statutes on behalf of the federal, state, and local governments. Qui tam complaints are initially filed by the relator under seal (or on a confidential basis) and the filing of the complaint imposes obligations on government authorities to investigate the allegations in the complaint and to determine whether or not to intervene in the action. Qui tam complaints remain sealed until the court in which the case was filed orders otherwise. Under the Federal False Claims Act, the government (or relators who pursue the claims without the participation of the government in the case) may seek to recover up to three times the amount of damages in addition to a civil penalty for each allegedly false claim submitted to the government for payment. Generally speaking, these cases take several years for the investigation to be completed and, ultimately, to be resolved (either through litigation or settlement) after the complaint is unsealed. In addition, some states have pursued investigations under state false claims statutes or consumer protection laws, either in conjunction with a government investigation or separately. There is often collateral litigation that arises from public disclosures of government investigations, including the filing of class action lawsuits by third party payors or by shareholders alleging violations of the securities laws. The Federal Food, Drug, and Cosmetic Act ("FDCA") contains provisions relating to the sale and distribution of pharmaceutical products that are alleged to be adulterated or misbranded. The FDCA includes strict-liability criminal offenses that can be pursued by the government for violations of the FDCA and which can result in the imposition of substantial fines and penalties against corporations and individuals. The Company has learned that there are filings in one or more federal district courts, including a qui tam complaint filed by one of its former employees, that are under seal and may involve allegations against the Company (and/or subsidiaries or businesses of the Company, including its group purchasing organization for oncologists and its oncology distribution business) relating to its distribution of certain pharmaceutical products to providers. Subpoenas and Ongoing Investigations From time to time, the Company receives subpoenas or requests for information from various government agencies relating to the Company's business or to the business of a customer, supplier, or other industry participant. The Company generally responds to such subpoenas and requests in a cooperative manner. These responses often require time and effort and can result in considerable costs being incurred by the Company. 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 health care industry, as well as to substantial settlements. Since fiscal 2012, the Company and its subsidiary AmerisourceBergen Specialty Group ("ABSG") have been responding to subpoenas from the United States Attorney's Office for the Eastern District of New York ("USAO-EDNY") requesting production of documents and information relating to ABSG's oncology distribution center and former pharmacy in Dothan, Alabama (including the practices and procedures of the former pharmacy's pre-filled syringe program), its group purchasing organization for oncologists, and intercompany transfers of certain oncology products, which the Company believes could be related in whole or in part to one or more of the qui tam actions that remain under seal. The Company has produced documents and has engaged in ongoing dialogue with the USAO-EDNY. The USAO-EDNY has expressed an intention to pursue potential civil and criminal charges based upon the FDCA and the False Claims Act. The Company is engaged in discussions with both the criminal and civil divisions of the USAO-EDNY to attempt to reach negotiated settlements of the potential charges. Any settlement or other resolution of these matters could have an adverse effect on our business, results of operations, or cash flows. No conclusion can be drawn at this time as to any likely outcome in these matters. In fiscal 2012, the Company's subsidiary AmerisourceBergen Drug Corporation ("ABDC") received a subpoena from the United States Attorney's Office for the District of New Jersey ("USAO-NJ") in connection with a grand jury proceeding requesting documents concerning ABDC's program for controlling and monitoring diversion of controlled substances into channels other than for legitimate medical, scientific, and industrial purposes. ABDC also received a subpoena from the Drug Enforcement Administration ("DEA") in connection with the matter. Since fiscal 2012, ABDC has received and responded to a number of subpoenas from both the USAO-NJ and DEA requesting grand jury testimony and additional information related to electronically stored information, documents concerning specific customers' purchases of controlled substances, and DEA audits. The Company continues to engage in dialogue with the USAO-NJ, including discussions to attempt to reach a negotiated settlement. No conclusion can be drawn at this time as to any likely outcome in this matter. Since fiscal 2013, the Company or ABDC has received subpoenas from the United States Attorney's Office for the District of Kansas and the United States Attorney's Office for the Northern District of Ohio in connection with grand jury proceedings requesting documents concerning ABDC's program for controlling and monitoring diversion of controlled substances into channels other than for legitimate medical, scientific and industrial purposes. As in the USAO-NJ matter described above, in addition to requesting information on ABDC's diversion control program generally, the subpoenas have also requested documents concerning specific customers' purchases of controlled substances. The Company has responded to the subpoenas and requests for information. Since fiscal 2016, the Company’s subsidiary U.S. Bioservices ("US Bio") has received requests for information from the United States Attorney’s Office for the Southern District of New York ("USAO-SDNY"), on behalf of itself and a number of states, relating to US Bio’s dispensing of one product and US Bio’s relationship with the manufacturer of the product. The Company is engaged in discussions with the USAO-SDNY and representatives on behalf of a number of states. No conclusion can be drawn at this time as to any likely outcome in this matter. In January 2017, US Bio received a subpoena for information from the USAO-EDNY relating to US Bio’s activities in connection with billing for products and making returns of potential overpayments to government payers. The Company is engaged in discussions with the USAO-EDNY and will be producing documents in response to the subpoena. The Company cannot predict the outcome of these ongoing investigations or their impact on the Company as uncertainty remains with regard to whether such matters will proceed to trial, whether settlements will be reached and the amount and terms of any such settlements. Outcomes may include settlements in significant amounts that are not currently estimable, limitations on the Company's conduct, the imposition of corporate integrity obligations and/or other civil and criminal penalties. State Proceedings In June 2012, the Attorney General of the State of West Virginia ("West Virginia AG") filed complaints, which were amended, in the Circuit Court of Boone County, West Virginia, against a number of pharmaceutical wholesale distributors, including the Company's subsidiary ABDC, alleging, among other claims, that the distributors failed to provide effective controls and procedures to guard against diversion of controlled substances for illegitimate purposes in West Virginia, acted negligently by distributing controlled substances to pharmacies that serve individuals who abuse controlled substances, and failed to report suspicious orders of uncontrolled substances in accordance with state regulations. The West Virginia AG was seeking monetary damages and injunctive and other equitable relief. This matter was dismissed with prejudice on January 9, 2017 pursuant to a settlement agreement that provided for the payment of $16.0 million and express denial of the allegations in the complaints and any wrongdoing. During the six months ended March 31, 2017, the Company recognized the $16.0 million settlement in Employee Severance, Litigation, and Other on the Company's Consolidated Statement of Operations. ABDC was sued in state court by McDowell County, West Virginia on December 23, 2016, with an Amended Complaint filed on February 24, 2017, asserting substantially similar claims to the West Virginia AG action, including for negligence, violation of the West Virginia Controlled Substances Act, unjust enrichment, public nuisance, and "Intentional Acts and Omissions." ABDC filed a notice of removal of this matter on January 26, 2017 and a motion to dismiss the Amended Complaint with prejudice on March 17, 2017. ABDC was sued in state court by the City of Huntington, West Virginia on January 20, 2017, with an Amended Complaint filed on January 26, 2017 but not served, asserting similar claims to the West Virginia AG and McDowell County actions, including for negligence, violation of the West Virginia Controlled Substances Act, and unjust enrichment. ABDC filed a notice of removal of this matter on February 23, 2017 and a motion to dismiss on March 2, 2017. Two additional cities, Kermit and Welch, have filed suit against ABDC asserting similar claims, but have not yet served their complaint on ABDC or any other defendant. Additionally, seven County Commissions (Boone, Cabell, Fayette, Kanawha, Logan, Wayne and Wyoming) have filed suit in Federal Court, each asserting a single claim for public nuisance. ABDC has filed a motion to dismiss each complaint for which a responsive pleading has been due and intends to file a motion to dismiss in each remaining case. Other jurisdictions, including West Virginia County Commissions, have indicated their intent to sue. ABDC intends to vigorously defend itself against the pending and 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. Other Litigation On September 10, 2014, PharMerica Corp., Pharmacy Corporation of America and Chem Rx Pharmacy Services, LLC (collectively, "PMC"), customers of ABDC until March 3, 2015, filed a complaint in Jefferson Circuit Court in Louisville, Kentucky against ABDC. The original complaint alleged that ABDC failed to pay in excess of $8 million in rebates pursuant to a prime vendor agreement between PMC and ABDC under which ABDC distributed pharmaceuticals and other products to PMC. PMC subsequently amended its complaint three times. PMC’s current complaint alleges unpaid-rebate claims in excess of $33 million and additional breaches and damages for unspecified amounts, which amounts may exceed $100 million . ABDC answered all of the complaints, denied PMC’s allegations, and filed counterclaims alleging, among other things, that PMC failed to pay nearly $50 million in invoices related to pharmaceutical products it received from ABDC. On April 1, 2016, the Jefferson Circuit Court granted ABDC’s motion for partial summary judgment on one counterclaim and entered judgment in the amount of $48.6 million against PMC. The Court determined that its ruling will not be final and appealable until after the other issues in the case are resolved, so the $48.6 million judgment is not collectible at this time. Fact and expert discovery have ended and the parties are currently preparing dispositive motions, which are scheduled to be briefed and argued by the end of August 2017. Trial is currently scheduled for January 30, 2018. The Company is not in a position to assess the likely outcome or its exposure, if any, with respect to this matter.

Litigation Settlements

Litigation Settlements	6 Months Ended
	Mar. 31, 2017
Litigation Settlement [Abstract]
Litigation Settlements	Litigation Settlements Antitrust Settlements Numerous class action 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. The Company has not been named a plaintiff in any of these class actions, but has been a member of the direct purchasers’ class (i.e., those purchasers who purchase directly from these pharmaceutical manufacturers). None of the class actions have gone to trial, but some have settled in the past with the Company receiving proceeds from the settlement funds. During the six months ended March 31, 2017 and 2016, the Company recognized gains of $1.4 million and $12.8 million , respectively, related to these class action lawsuits. These gains, which are net of attorney fees and estimated payments due to other parties, were recorded as reductions to cost of goods sold in the Company’s consolidated statements of operations.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	6 Months Ended
	Mar. 31, 2017
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 at March 31, 2017 and September 30, 2016 approximate fair value based upon the relatively short-term nature of these financial instruments. Within cash and cash equivalents, the Company had $1,000.0 million and $650.0 million of investments in money market accounts as of March 31, 2017 and September 30, 2016 , respectively. The fair value of the money market accounts was determined based on unadjusted quoted prices in active markets for identical assets, otherwise known as Level 1 inputs. The Company had $119.0 million of investment securities available-for-sale, $80.4 million of which were within cash and cash equivalents, at March 31, 2017 . The amortized cost of the investments was $119.0 million at March 31, 2017 . The Company had $39.1 million of investment securities available-for-sale, $13.0 million of which were within cash and cash equivalents, at September 30, 2016 . The amortized cost of the investments was $39.1 million at September 30, 2016 . The fair value of the investments was based on inputs other than quoted market prices, otherwise known as Level 2 inputs. The investments held as of March 31, 2017 consisted of fixed-income securities with maturities ranging from April 2017 to July 2017. The recorded amount of long-term debt (see Note 5) and the corresponding fair value as of March 31, 2017 were $3,478.2 million and $3,546.4 million , respectively. The recorded amount of long-term debt and the corresponding fair value as of September 30, 2016 were $3,576.5 million and $3,750.9 million , respectively. The fair value of long-term debt was determined based on Level 2 inputs, as defined above.

Business Segment Information

Business Segment Information	6 Months Ended
	Mar. 31, 2017
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. The Pharmaceutical Distribution Services reportable segment consists of the ABDC and ABSG operating segments. Other consists of operating segments that focus on manufacturer and other services and includes AmerisourceBergen Consulting Services ("ABCS"), World Courier, and MWI. The following tables illustrate reportable segment information for the three and six months ended March 31, 2017 and 2016 : Revenue Three months ended Six months ended (in thousands) 2017 2016 2017 2016 Pharmaceutical Distribution Services $ 35,518,955 $ 34,165,733 $ 72,094,922 $ 69,360,412 Other 1,696,137 1,599,805 3,359,791 3,177,620 Intersegment eliminations (67,690 ) (67,181 ) (138,046 ) (130,629 ) Revenue $ 37,147,402 $ 35,698,357 $ 75,316,667 $ 72,407,403 Intersegment eliminations primarily represent the elimination of certain ABCS sales to the Pharmaceutical Distribution Services reportable segment. Segment Operating Income Three months ended Six months ended (in thousands) 2017 2016 2017 2016 (As Revised) (As Revised) Pharmaceutical Distribution Services $ 482,265 $ 500,165 $ 856,267 $ 881,419 Other 106,206 93,956 218,412 189,521 Intersegment eliminations (1 ) — $ (14 ) $ — Total segment operating income $ 588,470 $ 594,121 $ 1,074,665 $ 1,070,940 The following table reconciles total segment operating income to income before income taxes: Income Before Income Taxes Three months ended Six months ended (in thousands) 2017 2016 2017 2016 (As Revised) (As Revised) Total segment operating income $ 588,470 $ 594,121 $ 1,074,665 $ 1,070,940 Gain from antitrust litigation settlements — 7 1,395 12,798 LIFO credit (expense) 86,504 (92,379 ) 58,196 (193,941 ) Acquisition-related intangibles amortization (38,059 ) (38,720 ) (76,288 ) (69,930 ) Warrants income — 503,946 — 36,571 Employee severance, litigation, and other (11,934 ) (17,617 ) (33,000 ) (36,485 ) Pension settlement — 1,124 — (47,607 ) Operating income 624,981 950,482 1,024,968 772,346 Other income (5,233 ) (756 ) (5,356 ) (1,066 ) Interest expense, net 37,299 35,966 74,271 69,707 Income before income taxes $ 592,915 $ 915,272 $ 956,053 $ 703,705 Segment operating income is evaluated by the chief operating decision maker of the Company before gain from antitrust litigation settlements; LIFO credit (expense); acquisition-related intangibles amortization; Warrants income; employee severance, litigation, and other; pension settlement; other income; and interest expense, net. All corporate office expenses are allocated to each operating segment.

Summary of Significant Accoun19

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation	The accompanying financial statements present the consolidated financial position, results of operations, and cash flows of AmerisourceBergen Corporation and its wholly-owned subsidiaries (the "Company") as of the dates and for the periods indicated. All intercompany accounts and transactions have been eliminated in consolidation. The accompanying unaudited consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles ("GAAP") for interim financial information, the instructions to Form 10-Q, and Rule 10-01 of Regulation S-X. In the opinion of management, all adjustments (consisting only of normal recurring accruals, except as otherwise disclosed herein) considered necessary to present fairly the financial position as of March 31, 2017 and the results of operations and cash flows for the interim periods ended March 31, 2017 and 2016 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, 2016 .
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. Certain reclassifications have been made to prior-period amounts in order to conform to the current year presentation.
New Accounting Pronouncements	Recently Adopted Accounting Pronouncements In April 2015, the FASB issued ASU No. 2015-03, "Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs" ("ASU 2015-03"). ASU 2015-03 specifies that debt issuance costs related to a debt liability shall be reported on the balance sheet as a direct reduction from the face amount of the debt liability. In August 2015, the FASB issued ASU No. 2015-15, "Interest - Imputation of Interest (Subtopic 835-30): Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements" ("ASU 2015-15"). ASU 2015-15 specifies that debt issuance costs related to line-of-credit arrangements may be presented as an asset on the balance sheet and subsequently amortized ratably over the term of the line-of-credit arrangement, regardless of whether there are any outstanding borrowings on the line-of-credit arrangement. As of October 1, 2016, the Company adopted ASU 2015-03 and ASU 2015-15, which resulted in the reclassification of $18.7 million of debt issuance costs from Other Assets to Short-Term Debt of $0.9 million and to Long-Term Debt of $17.8 million on the Company's September 30, 2016 Consolidated Balance Sheet. The adoption had no impact on the Company’s results of operations or cash flows. In March 2016, the FASB issued ASU No. 2016-09, "Compensation — Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting" ("ASU 2016-09"). ASU 2016-09 requires all income tax effects of awards to be recognized in the income statement when the awards vest or are settled. It also allows an employer to repurchase more of an employee's shares than it may currently for tax withholding purposes without triggering liability accounting and to make a policy election to account for forfeitures as they occur. ASU 2016-09 is effective for annual reporting periods beginning after December 15, 2016 and interim periods within those fiscal years. Entities are permitted to adopt the standard early in any interim or annual period. During the quarter ended December 31, 2016, the Company early adopted ASU 2016-09, which resulted in a cumulative adjustment to retained earnings and established a deferred tax asset as of October 1, 2016 of $47.1 million for previously unrecognized tax benefits. The Company elected to adopt the Statement of Cash Flows presentation of the excess tax benefits prospectively. During the three and six months ended March 31, 2017 , the Company recognized tax benefits of $19.8 million and $24.0 million , respectively, in Income Tax Expense on the Company's Consolidated Statement of Operations. The tax benefits recognized in the three and six months ended March 31, 2017 are not necessarily indicative of amounts that may arise in future periods. Recently Issued Accounting Pronouncements Not Yet Adopted In May 2014, the FASB issued ASU No. 2014-09, "Revenue from Contracts with Customers (Topic 606)" ("ASU 2014-09"). ASU 2014-09 supersedes the revenue recognition requirements in Accounting Standards Codification 605 — "Revenue Recognition" and most industry-specific guidance throughout the Codification. ASU 2014-09 outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers. The standard's core principle is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 was originally scheduled to be effective for annual reporting periods beginning after December 15, 2016, including interim periods within those reporting periods. In July 2015, the Financial Accounting Standards Board deferred the effective date of ASU 2014-09 by one year. In March 2016, the FASB issued ASU No. 2016-08, "Revenue from Contracts with Customers (Topic 606) — Principal versus Agent Considerations" ("ASU 2016-08"), which clarifies the implementation guidance for principal versus agent considerations in ASU 2014-09. In April 2016, the FASB issued ASU No. 2016-10, "Revenue from Contracts with Customers (Topic 606) — Identifying Performance Obligations and Licensing" ("ASU 2016-10"), which amends the guidance in ASU 2014-09 related to identifying performance obligations and accounting for licenses of intellectual property. The Company must adopt ASU 2016-08 and ASU 2016-10 with ASU 2014-09. Entities are permitted to adopt the standards as early as the original public entity effective date of ASU 2014-09, and either full or modified retrospective application is required. The Company has not yet selected an adoption date or a transition method for ASU 2014-09, 2016-08, and 2016-10 and is currently evaluating the impact of adopting this new accounting guidance and, therefore, cannot reasonably estimate the impact that the adoption of the above standards will have on its financial statements. In February 2016, the FASB issued ASU No. 2016-02, "Leases (Topic 842)" ("ASU 2016-02"). ASU 2016-02 aims to increase transparency and comparability across organizations by requiring lease assets and lease liabilities to be recognized on the balance sheet as well as key information to be disclosed regarding lease arrangements. ASU 2016-02 is effective for annual reporting periods beginning after December 15, 2018, and interim periods within those fiscal years. Entities are permitted to adopt the standard early, and a modified retrospective application is required. The Company is currently evaluating the impact of adopting this new accounting guidance and, therefore, cannot reasonably estimate the impact that the adoption of this standard will have on its financial statements. In August 2016, the FASB issued ASU No. 2016-15, "Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments" ("ASU 2016-15"). ASU 2016-15 aims to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. ASU 2016-15 is effective for annual reporting periods beginning after December 15, 2017 and interim periods within those fiscal years. Entities are permitted to adopt the standard early in any interim or annual period, and a retrospective application is required. The Company is currently evaluating the impact of adopting this new accounting guidance and, therefore, cannot reasonably estimate the impact that the adoption of this standard will have on its financial statements. In January 2017, the FASB issued ASU No. 2017-04, "Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment" ("ASU 2017-04"). ASU 2017-04 removes Step 2 of the goodwill impairment test, which requires a hypothetical purchase price allocation. A goodwill impairment will now be the amount by which a reporting unit’s carrying value exceeds its fair value. ASU 2017-04 is effective for annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Entities are permitted to adopt the standard early for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company does not expect that the adoption of this standard will impact the Company's results of operations, cash flows, or financial position. As of March 31, 2017 , 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.

Revision of Previously Issued20

Revision of Previously Issued Financial Statements (Tables)	6 Months Ended
	Mar. 31, 2017
Accounting Changes and Error Corrections [Abstract]
Impact of adjustments on previously issued financial statements	The following illustrates the impact the aforementioned adjustments had on the Company's previously issued financial statements: CONSOLIDATED STATEMENT OF OPERATIONS Three months ended March 31, 2016 (in thousands, except per share data) As Previously Reported Adjustments As Revised Revenue $ 35,698,357 $ — $ 35,698,357 Cost of goods sold 34,623,026 — 34,623,026 Gross profit 1,075,331 — 1,075,331 Operating expenses: Distribution, selling, and administrative 522,760 (3,294 ) 519,466 Depreciation 51,471 1,524 52,995 Amortization 39,841 — 39,841 Warrants (503,946 ) — (503,946 ) Employee severance, litigation, and other 17,617 — 17,617 Pension settlement (1,124 ) — (1,124 ) Operating income 948,712 1,770 950,482 Other income (756 ) — (756 ) Interest expense, net 33,113 2,853 35,966 Income before income taxes 916,355 (1,083 ) 915,272 Income tax expense 312,220 (398 ) 311,822 Net income $ 604,135 $ (685 ) $ 603,450 Earnings per share: Basic $ 2.91 $ (0.01 ) $ 2.90 Diluted $ 2.68 $ — $ 2.68 Weighted average common shares outstanding: Basic 207,858 — 207,858 Diluted 225,450 — 225,450 CONSOLIDATED STATEMENT OF OPERATIONS Six months ended March 31, 2016 (in thousands, except per share data) As Previously Reported Adjustments As Revised Revenue $ 72,407,403 $ — $ 72,407,403 Cost of goods sold 70,367,195 — 70,367,195 Gross profit 2,040,208 — 2,040,208 Operating expenses: Distribution, selling, and administrative 1,051,056 (6,513 ) 1,044,543 Depreciation 100,813 3,048 103,861 Amortization 71,937 — 71,937 Warrants (36,571 ) — (36,571 ) Employee severance, litigation, and other 36,485 — 36,485 Pension settlement 47,607 — 47,607 Operating income 768,881 3,465 772,346 Other income (1,066 ) — (1,066 ) Interest expense, net 63,992 5,715 69,707 Income before income taxes 705,955 (2,250 ) 703,705 Income tax benefit (228,557 ) (827 ) (229,384 ) Net income $ 934,512 $ (1,423 ) $ 933,089 Earnings per share: Basic $ 4.51 $ — $ 4.51 Diluted $ 4.13 $ — $ 4.13 Weighted average common shares outstanding: Basic 207,017 — 207,017 Diluted 226,082 — 226,082 CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME Three months ended March 31, 2016 (in thousands) As Previously Reported Adjustments As Revised Net income $ 604,135 $ (685 ) $ 603,450 Other comprehensive income: Net change in foreign currency translation adjustments 13,911 — 13,911 Other (281 ) — (281 ) Total other comprehensive income 13,630 — 13,630 Total comprehensive income $ 617,765 $ (685 ) $ 617,080 Six months ended March 31, 2016 (in thousands) As Previously Reported Adjustments As Revised Net income $ 934,512 $ (1,423 ) $ 933,089 Other comprehensive income: Net change in foreign currency translation adjustments 3,477 — 3,477 Pension plan adjustment, net of tax of $19,054 31,538 — 31,538 Other (866 ) — (866 ) Total other comprehensive income 34,149 — 34,149 Total comprehensive income $ 968,661 $ (1,423 ) $ 967,238 CONSOLIDATED STATEMENT OF CASH FLOWS Six months ended March 31, 2016 (in thousands) As Previously Reported Adjustments As Revised OPERATING ACTIVITIES Net income $ 934,512 $ (1,423 ) $ 933,089 Adjustments to reconcile net income to net cash provided by operating activities: Depreciation, including amounts charged to cost of goods sold 109,796 3,048 112,844 Amortization, including amounts charged to interest expense 75,144 241 75,385 Provision for doubtful accounts 8,065 — 8,065 Benefit for deferred income taxes (292,154 ) (827 ) (292,981 ) Warrants income (36,571 ) — (36,571 ) Share-based compensation 39,787 — 39,787 LIFO expense 1 193,941 — 193,941 Pension settlement 47,607 — 47,607 Other (193 ) — (193 ) Changes in operating assets and liabilities, excluding the effects of acquisitions: Accounts receivable (472,074 ) — (472,074 ) Merchandise inventories 1 (1,047,018 ) — (1,047,018 ) Prepaid expenses and other assets 17,642 — 17,642 Accounts payable 2,070,716 — 2,070,716 Accrued expenses, income taxes, and other liabilities (18,614 ) 395 (18,219 ) NET CASH PROVIDED BY OPERATING ACTIVITIES 1,630,586 1,434 1,632,020 INVESTING ACTIVITIES Capital expenditures (180,012 ) — (180,012 ) Cost of acquired companies, net of cash acquired (2,731,356 ) — (2,731,356 ) Proceeds from sales of investment securities available-for-sale 88,829 — 88,829 Purchases of investment securities available-for-sale (41,136 ) — (41,136 ) Other (10,878 ) — (10,878 ) NET CASH USED IN INVESTING ACTIVITIES (2,874,553 ) — (2,874,553 ) FINANCING ACTIVITIES Term loan borrowings 1,000,000 — 1,000,000 Term loan repayments (25,000 ) — (25,000 ) Borrowings under revolving and securitization credit facilities 8,237,792 — 8,237,792 Repayments under revolving and securitization credit facilities (8,217,849 ) — (8,217,849 ) Purchases of common stock (436,804 ) — (436,804 ) Exercises of warrants 1,168,891 — 1,168,891 Exercises of stock options 37,285 — 37,285 Cash dividends on common stock (141,829 ) — (141,829 ) Tax withholdings related to restricted share vesting (18,233 ) — (18,233 ) Other (2,441 ) (1,434 ) (3,875 ) NET CASH PROVIDED BY FINANCING ACTIVITIES 1,601,812 (1,434 ) 1,600,378 INCREASE IN CASH AND CASH EQUIVALENTS 357,845 — 357,845 Cash and cash equivalents at beginning of period 2,167,442 — 2,167,442 CASH AND CASH EQUIVALENTS AT END OF PERIOD $ 2,525,287 $ — $ 2,525,287 1 Amounts as previously reported have been revised to report LIFO Expense separately from the change in Merchandise Inventories.

Goodwill and Other Intangible21

Goodwill and Other Intangible Assets (Tables)	6 Months Ended
	Mar. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of changes in the carrying value of goodwill by reportable segment	Following is a summary of the changes in the carrying value of goodwill, by reportable segment, for the six months ended March 31, 2017 : (in thousands) Pharmaceutical Distribution Services Other Total Goodwill at September 30, 2016 $ 4,264,485 $ 1,727,012 $ 5,991,497 Goodwill recognized in connection with acquisition — 1,044 1,044 Goodwill disposed in connection with divestiture — (3,564 ) (3,564 ) Foreign currency translation — (1,248 ) (1,248 ) Goodwill at March 31, 2017 $ 4,264,485 $ 1,723,244 $ 5,987,729
Schedule of indefinite-lived intangible assets	Following is a summary of other intangible assets: March 31, 2017 September 30, 2016 (in thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Indefinite-lived trade names $ 684,965 $ — $ 684,965 $ 684,991 $ — $ 684,991 Finite-lived: Customer relationships 2,320,994 (340,662 ) 1,980,332 2,322,404 (273,638 ) 2,048,766 Trade names and other 308,473 (84,850 ) 223,623 307,234 (73,142 ) 234,092 Total other intangible assets $ 3,314,432 $ (425,512 ) $ 2,888,920 $ 3,314,629 $ (346,780 ) $ 2,967,849
Schedule of finite-lived intangible assets	Following is a summary of other intangible assets: March 31, 2017 September 30, 2016 (in thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Indefinite-lived trade names $ 684,965 $ — $ 684,965 $ 684,991 $ — $ 684,991 Finite-lived: Customer relationships 2,320,994 (340,662 ) 1,980,332 2,322,404 (273,638 ) 2,048,766 Trade names and other 308,473 (84,850 ) 223,623 307,234 (73,142 ) 234,092 Total other intangible assets $ 3,314,432 $ (425,512 ) $ 2,888,920 $ 3,314,629 $ (346,780 ) $ 2,967,849

Debt (Tables)

Debt (Tables)	6 Months Ended
	Mar. 31, 2017
Debt Disclosure [Abstract]
Schedule of debt instruments	Debt consisted of the following: (in thousands) March 31, September 30, Revolving credit note $ — $ — Receivables securitization facility due 2019 500,000 500,000 Term loans due in 2020 597,458 697,055 Multi-currency revolving credit facility due 2021 — — Overdraft facility due 2021 16,053 11,275 $600,000, 1.15% senior notes due 2017 599,794 598,935 $400,000, 4.875% senior notes due 2019 398,034 397,669 $500,000, 3.50% senior notes due 2021 497,619 497,361 $500,000, 3.40% senior notes due 2024 496,521 496,276 $500,000, 3.25% senior notes due 2025 494,608 494,266 $500,000, 4.25% senior notes due 2045 493,974 493,866 Total debt 4,094,061 4,186,703 Less current portion 615,847 610,210 Total, net of current portion $ 3,478,214 $ 3,576,493

Stockholders' Equity and Earn23

Stockholders' Equity and Earnings per Share (Tables)	6 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Schedule of weighted average number of common shares outstanding	Three months ended Six months ended (in thousands) 2017 2016 2017 2016 Weighted average common shares outstanding - basic 217,650 207,858 218,166 207,017 Dilutive effect of stock options, restricted stock, and restricted stock units 3,571 3,421 3,445 3,639 Dilutive effect of Warrants — 14,171 — 15,426 Weighted average common shares outstanding - diluted 221,221 225,450 221,611 226,082

Business Segment Information (T

Business Segment Information (Tables)	6 Months Ended
	Mar. 31, 2017
Segment Reporting [Abstract]
Segment revenue	The following tables illustrate reportable segment information for the three and six months ended March 31, 2017 and 2016 : Revenue Three months ended Six months ended (in thousands) 2017 2016 2017 2016 Pharmaceutical Distribution Services $ 35,518,955 $ 34,165,733 $ 72,094,922 $ 69,360,412 Other 1,696,137 1,599,805 3,359,791 3,177,620 Intersegment eliminations (67,690 ) (67,181 ) (138,046 ) (130,629 ) Revenue $ 37,147,402 $ 35,698,357 $ 75,316,667 $ 72,407,403
Segment operating income	Segment Operating Income Three months ended Six months ended (in thousands) 2017 2016 2017 2016 (As Revised) (As Revised) Pharmaceutical Distribution Services $ 482,265 $ 500,165 $ 856,267 $ 881,419 Other 106,206 93,956 218,412 189,521 Intersegment eliminations (1 ) — $ (14 ) $ — Total segment operating income $ 588,470 $ 594,121 $ 1,074,665 $ 1,070,940
Reconciliation of total segment operating income to income (loss) from operations before income taxes	The following table reconciles total segment operating income to income before income taxes: Income Before Income Taxes Three months ended Six months ended (in thousands) 2017 2016 2017 2016 (As Revised) (As Revised) Total segment operating income $ 588,470 $ 594,121 $ 1,074,665 $ 1,070,940 Gain from antitrust litigation settlements — 7 1,395 12,798 LIFO credit (expense) 86,504 (92,379 ) 58,196 (193,941 ) Acquisition-related intangibles amortization (38,059 ) (38,720 ) (76,288 ) (69,930 ) Warrants income — 503,946 — 36,571 Employee severance, litigation, and other (11,934 ) (17,617 ) (33,000 ) (36,485 ) Pension settlement — 1,124 — (47,607 ) Operating income 624,981 950,482 1,024,968 772,346 Other income (5,233 ) (756 ) (5,356 ) (1,066 ) Interest expense, net 37,299 35,966 74,271 69,707 Income before income taxes $ 592,915 $ 915,272 $ 956,053 $ 703,705

Summary of Significant Accoun25

Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Mar. 31, 2017	Mar. 31, 2017	Oct. 01, 2016	Sep. 30, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Excess tax benefits, share-based compensation	$ 19.8	$ 24
Accounting Standards Update 2015-03 | Other assets
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs				$ (18.7)
Accounting Standards Update 2015-03 | Short-term debt
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs				0.9
Accounting Standards Update 2015-03 | Long-term debt
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs				$ 17.8
Accounting Standards Update 2016-09 | New Accounting Pronouncement, Early Adoption, Effect
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred tax asset, share-based compensation			$ 47.1
Accounting Standards Update 2016-09 | New Accounting Pronouncement, Early Adoption, Effect | Retained earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment, share-based compensation			$ 47.1

Revision of Previously Issued26

Revision of Previously Issued Financial Statements - Consolidated Statements of Operations (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue	$ 37,147,402	$ 35,698,357	$ 75,316,667	$ 72,407,403
Cost of goods sold	35,890,975	34,623,026	73,022,560	70,367,195
Gross profit	1,256,427	1,075,331	2,294,107	2,040,208
Operating expenses:
Distribution, selling, and administrative	521,843	519,466	1,042,390	1,044,543
Depreciation	57,751	52,995	113,605	103,861
Amortization	39,918	39,841	80,144	71,937
Warrants	0	(503,946)	0	(36,571)
Employee severance, litigation, and other	11,934	17,617	33,000	36,485
Pension settlement	0	(1,124)	0	47,607
Operating income	624,981	950,482	1,024,968	772,346
Other income	(5,233)	(756)	(5,356)	(1,066)
Interest expense, net	37,299	35,966	74,271	69,707
Income before income taxes	592,915	915,272	956,053	703,705
Income tax expense (benefit)	181,442	311,822	297,334	(229,384)
Net income	$ 411,473	$ 603,450	$ 658,719	$ 933,089
Earnings per share:
Basic (usd per share)	$ 1.89	$ 2.90	$ 3.02	$ 4.51
Diluted (usd per share)	$ 1.86	$ 2.68	$ 2.97	$ 4.13
Weighted average common shares outstanding:
Basic (shares)	217,650	207,858	218,166	207,017
Diluted (shares)	221,221	225,450	221,611	226,082
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue		$ 35,698,357		$ 72,407,403
Cost of goods sold		34,623,026		70,367,195
Gross profit		1,075,331		2,040,208
Operating expenses:
Distribution, selling, and administrative		522,760		1,051,056
Depreciation		51,471		100,813
Amortization		39,841		71,937
Warrants		(503,946)		(36,571)
Employee severance, litigation, and other		17,617		36,485
Pension settlement		(1,124)		47,607
Operating income		948,712		768,881
Other income		(756)		(1,066)
Interest expense, net		33,113		63,992
Income before income taxes		916,355		705,955
Income tax expense (benefit)		312,220		(228,557)
Net income		$ 604,135		$ 934,512
Earnings per share:
Basic (usd per share)		$ 2.91		$ 4.51
Diluted (usd per share)		$ 2.68		$ 4.13
Weighted average common shares outstanding:
Basic (shares)		207,858		207,017
Diluted (shares)		225,450		226,082
Adjustments | Error Correction, Lease Accounting
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue		$ 0		$ 0
Cost of goods sold		0		0
Gross profit		0		0
Operating expenses:
Distribution, selling, and administrative		(3,294)		(6,513)
Depreciation		1,524		3,048
Amortization		0		0
Warrants		0		0
Employee severance, litigation, and other		0		0
Pension settlement		0		0
Operating income		1,770		3,465
Other income		0		0
Interest expense, net		2,853		5,715
Income before income taxes		(1,083)		(2,250)
Income tax expense (benefit)		(398)		(827)
Net income		$ (685)		$ (1,423)
Earnings per share:
Basic (usd per share)		$ (0.01)		$ 0
Diluted (usd per share)		$ 0		$ 0
Weighted average common shares outstanding:
Basic (shares)		0		0
Diluted (shares)		0		0

Revision of Previously Issued27

Revision of Previously Issued Financial Statements - Consolidated Statements of Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income	$ 411,473	$ 603,450	$ 658,719	$ 933,089
Other comprehensive income (loss)
Net change in foreign currency translation adjustments	18,545	13,911	(9,012)	3,477
Pension plan adjustment, net of tax of $19,054	0	0	0	31,538
Other	(184)	(281)	(170)	(866)
Total other comprehensive income (loss)	18,361	13,630	(9,182)	34,149
Total comprehensive income	$ 429,834	617,080	$ 649,537	967,238
Other comprehensive income (loss), parenthetical disclosures:
Pension plan adjustments, tax				19,054
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income		604,135		934,512
Other comprehensive income (loss)
Net change in foreign currency translation adjustments		13,911		3,477
Pension plan adjustment, net of tax of $19,054				31,538
Other		(281)		(866)
Total other comprehensive income (loss)		13,630		34,149
Total comprehensive income		617,765		968,661
Other comprehensive income (loss), parenthetical disclosures:
Pension plan adjustments, tax				19,054
Adjustments | Error Correction, Lease Accounting
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income		(685)		(1,423)
Other comprehensive income (loss)
Net change in foreign currency translation adjustments		0		0
Pension plan adjustment, net of tax of $19,054				0
Other		0		0
Total other comprehensive income (loss)		0		0
Total comprehensive income		$ (685)		(1,423)
Other comprehensive income (loss), parenthetical disclosures:
Pension plan adjustments, tax				$ 0

Revision of Previously Issued28

Revision of Previously Issued Financial Statements - Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
OPERATING ACTIVITIES
Net income	$ 411,473	$ 603,450	$ 658,719	$ 933,089
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, including amounts charged to cost of goods sold			127,184	112,844
Amortization, including amounts charged to interest expense			85,194	75,385
Provision for doubtful accounts			5,384	8,065
Provision (benefit) for deferred income taxes			159,397	(292,981)
Warrants income			0	(36,571)
Share-based compensation			41,250	39,787
LIFO (credit) expense			(58,196)	193,941
Pension settlement	0	(1,124)	0	47,607
Other			(6,809)	(193)
Changes in operating assets and liabilities, excluding the effects of acquisitions and divestitures:
Accounts receivable			(417,705)	(472,074)
Merchandise inventories			(556,057)	(1,047,018)
Prepaid expenses and other assets			26,591	17,642
Accounts payable			350,960	2,070,716
Accrued expenses, income taxes, and other liabilities			(47,528)	(18,219)
NET CASH PROVIDED BY OPERATING ACTIVITIES			368,384	1,632,020
INVESTING ACTIVITIES
Capital expenditures			(262,700)	(180,012)
Cost of acquired companies, net of cash acquired			(2,403)	(2,731,356)
Proceeds from sales of investment securities available-for-sale			36,128	88,829
Purchases of investment securities available-for-sale			(48,635)	(41,136)
Other			8,136	(10,878)
NET CASH USED IN INVESTING ACTIVITIES			(269,474)	(2,874,553)
FINANCING ACTIVITIES
Term loan borrowings			0	1,000,000
Term loan repayments			(100,000)	(25,000)
Borrowings under revolving and securitization credit facilities			6,711,081	8,237,792
Repayments under revolving and securitization credit facilities			(6,705,964)	(8,217,849)
Purchases of common stock			(229,928)	(436,804)
Exercises of warrants			0	1,168,891
Exercises of stock options			61,383	37,285
Cash dividends on common stock			(160,093)	(141,829)
Tax withholdings related to restricted share vesting			(8,968)	(18,233)
Other			(3,820)	(3,875)
NET CASH (USED IN) PROVIDED BY FINANCING ACTIVITIES			(436,309)	1,600,378
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS			(337,399)	357,845
Cash and cash equivalents at beginning of period			2,741,832	2,167,442
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 2,404,433	2,525,287	$ 2,404,433	2,525,287
As Previously Reported
OPERATING ACTIVITIES
Net income		604,135		934,512
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, including amounts charged to cost of goods sold				109,796
Amortization, including amounts charged to interest expense				75,144
Provision for doubtful accounts				8,065
Provision (benefit) for deferred income taxes				(292,154)
Warrants income				(36,571)
Share-based compensation				39,787
LIFO (credit) expense				193,941
Pension settlement		(1,124)		47,607
Other				(193)
Changes in operating assets and liabilities, excluding the effects of acquisitions and divestitures:
Accounts receivable				(472,074)
Merchandise inventories				(1,047,018)
Prepaid expenses and other assets				17,642
Accounts payable				2,070,716
Accrued expenses, income taxes, and other liabilities				(18,614)
NET CASH PROVIDED BY OPERATING ACTIVITIES				1,630,586
INVESTING ACTIVITIES
Capital expenditures				(180,012)
Cost of acquired companies, net of cash acquired				(2,731,356)
Proceeds from sales of investment securities available-for-sale				88,829
Purchases of investment securities available-for-sale				(41,136)
Other				(10,878)
NET CASH USED IN INVESTING ACTIVITIES				(2,874,553)
FINANCING ACTIVITIES
Term loan borrowings				1,000,000
Term loan repayments				(25,000)
Borrowings under revolving and securitization credit facilities				8,237,792
Repayments under revolving and securitization credit facilities				(8,217,849)
Purchases of common stock				(436,804)
Exercises of warrants				1,168,891
Exercises of stock options				37,285
Cash dividends on common stock				(141,829)
Tax withholdings related to restricted share vesting				(18,233)
Other				(2,441)
NET CASH (USED IN) PROVIDED BY FINANCING ACTIVITIES				1,601,812
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS				357,845
Cash and cash equivalents at beginning of period				2,167,442
CASH AND CASH EQUIVALENTS AT END OF PERIOD		2,525,287		2,525,287
Adjustments | Error Correction, Lease Accounting
OPERATING ACTIVITIES
Net income		(685)		(1,423)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, including amounts charged to cost of goods sold				3,048
Amortization, including amounts charged to interest expense				241
Provision for doubtful accounts				0
Provision (benefit) for deferred income taxes				(827)
Warrants income				0
Share-based compensation				0
LIFO (credit) expense				0
Pension settlement		0		0
Other				0
Changes in operating assets and liabilities, excluding the effects of acquisitions and divestitures:
Accounts receivable				0
Merchandise inventories				0
Prepaid expenses and other assets				0
Accounts payable				0
Accrued expenses, income taxes, and other liabilities				395
NET CASH PROVIDED BY OPERATING ACTIVITIES				1,434
INVESTING ACTIVITIES
Capital expenditures				0
Cost of acquired companies, net of cash acquired				0
Proceeds from sales of investment securities available-for-sale				0
Purchases of investment securities available-for-sale				0
Other				0
NET CASH USED IN INVESTING ACTIVITIES				0
FINANCING ACTIVITIES
Term loan borrowings				0
Term loan repayments				0
Borrowings under revolving and securitization credit facilities				0
Repayments under revolving and securitization credit facilities				0
Purchases of common stock				0
Exercises of warrants				0
Exercises of stock options				0
Cash dividends on common stock				0
Tax withholdings related to restricted share vesting				0
Other				(1,434)
NET CASH (USED IN) PROVIDED BY FINANCING ACTIVITIES				(1,434)
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS				0
Cash and cash equivalents at beginning of period				0
CASH AND CASH EQUIVALENTS AT END OF PERIOD		$ 0		$ 0

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 99.2		$ 99.2
Unrecognized tax benefits, net of federal benefit	71.1		71.1
Unrecognized tax benefits - interest and penalties	14		14
Unrecognized tax benefits - increase (decrease)			11
Significant change in unrecognized tax benefits is reasonably possible	$ 4.7		$ 4.7
Effective tax rate	30.60%	34.10%	31.10%	(32.60%)

Goodwill and Other Intangible30

Goodwill and Other Intangible Assets - Schedule of Change in the Carrying Value of Goodwill by Reportable Segment (Details) $ in Thousands	6 Months Ended
	Mar. 31, 2017USD ($)
Goodwill [Roll Forward]
Goodwill	$ 5,991,497
Goodwill recognized in connection with acquisition	1,044
Goodwill disposed in connection with divestiture	(3,564)
Foreign currency translation	(1,248)
Goodwill	5,987,729
Operating segments | Pharmaceutical Distribution Services
Goodwill [Roll Forward]
Goodwill	4,264,485
Goodwill recognized in connection with acquisition	0
Goodwill disposed in connection with divestiture	0
Foreign currency translation	0
Goodwill	4,264,485
Operating segments | Other
Goodwill [Roll Forward]
Goodwill	1,727,012
Goodwill recognized in connection with acquisition	1,044
Goodwill disposed in connection with divestiture	(3,564)
Foreign currency translation	(1,248)
Goodwill	$ 1,723,244

Goodwill and Other Intangible31

Goodwill and Other Intangible Assets - Schedule of Other Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Sep. 30, 2016
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangibles, Accumulated Amortization	$ (425,512)	$ (346,780)
Indefinite-lived intangibles
Gross Carrying Amount	3,314,432	3,314,629
Net Carrying Amount	2,888,920	2,967,849
Trade names
Indefinite-lived intangibles
Indefinite-lived intangibles	684,965	684,991
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangibles, Gross Carrying Amount	2,320,994	2,322,404
Finite-lived intangibles, Accumulated Amortization	(340,662)	(273,638)
Finite-lived intangibles, Net Carrying Amount	1,980,332	2,048,766
Trade names and other
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangibles, Gross Carrying Amount	308,473	307,234
Finite-lived intangibles, Accumulated Amortization	(84,850)	(73,142)
Finite-lived intangibles, Net Carrying Amount	$ 223,623	$ 234,092

Goodwill and Other Intangible32

Goodwill and Other Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense	$ 40.2	$ 39.8	$ 80.4	$ 71.9
Amortization expense, fiscal year maturity
2,017	160.2		160.2
2,018	158.1		158.1
2,019	153.4		153.4
2,020	149.2		149.2
2,021	148.3		148.3
Thereafter	$ 1,515.2		$ 1,515.2

Debt - Schedule of Debt Instrum

Debt - Schedule of Debt Instruments (Details) - USD ($)	Mar. 31, 2017	Sep. 30, 2016
Debt Instrument [Line Items]
Long-term debt	$ 4,094,061,000	$ 4,186,703,000
Less current portion	615,847,000	610,210,000
Total, net of current portion	3,478,214,000	3,576,493,000
Revolving credit note
Debt Instrument [Line Items]
Long-term debt	0	0
Receivables securitization facility due 2019
Debt Instrument [Line Items]
Long-term debt	500,000,000	500,000,000
Term loans due in 2020
Debt Instrument [Line Items]
Long-term debt	597,458,000	697,055,000
Multi-currency revolving credit facility due 2021
Debt Instrument [Line Items]
Long-term debt	0	0
Overdraft facility due 2021
Debt Instrument [Line Items]
Long-term debt	16,053,000	11,275,000
$600,000, 1.15% senior notes due 2017
Debt Instrument [Line Items]
Principal amount	$ 600,000,000
Interest rate	1.15%
Long-term debt	$ 599,794,000	598,935,000
$400,000, 4.875% senior notes due 2019
Debt Instrument [Line Items]
Principal amount	$ 400,000,000
Interest rate	4.875%
Long-term debt	$ 398,034,000	397,669,000
$500,000, 3.50% senior notes due 2021
Debt Instrument [Line Items]
Principal amount	$ 500,000,000
Interest rate	3.50%
Long-term debt	$ 497,619,000	497,361,000
$500,000, 3.40% senior notes due 2024
Debt Instrument [Line Items]
Principal amount	$ 500,000,000
Interest rate	3.40%
Long-term debt	$ 496,521,000	496,276,000
$500,000, 3.25% senior notes due 2025
Debt Instrument [Line Items]
Principal amount	$ 500,000,000
Interest rate	3.25%
Long-term debt	$ 494,608,000	494,266,000
$500,000, 4.25% senior notes due 2045
Debt Instrument [Line Items]
Principal amount	$ 500,000,000
Interest rate	4.25%
Long-term debt	$ 493,974,000	$ 493,866,000

Debt - Additional information (

Debt - Additional information (Details)	1 Months Ended		6 Months Ended		17 Months Ended	26 Months Ended
	Nov. 30, 2015USD ($)	Feb. 28, 2015USD ($)	Mar. 31, 2017USD ($)	Mar. 31, 2016USD ($)	Mar. 31, 2017USD ($)	Mar. 31, 2017USD ($)	Mar. 31, 2017GBP (£)	Mar. 31, 2017USD ($)
Debt Instrument [Line Items]
Repayments of long-term debt			$ 100,000,000	$ 25,000,000
Multi-currency revolving credit facility due 2021
Debt Instrument [Line Items]
Maximum borrowing capacity								$ 1,400,000,000
Facility fee			0.09%
Multi-currency revolving credit facility due 2021 | Minimum
Debt Instrument [Line Items]
Facility fee			0.05%
Multi-currency revolving credit facility due 2021 | Maximum
Debt Instrument [Line Items]
Facility fee			0.15%
Multi-currency revolving credit facility due 2021 | CDOR / LIBOR / EURIBOR / Bankers Acceptance Stamping Fee
Debt Instrument [Line Items]
Variable rate spread			0.91%
Multi-currency revolving credit facility due 2021 | CDOR / LIBOR / EURIBOR / Bankers Acceptance Stamping Fee | Minimum
Debt Instrument [Line Items]
Variable rate spread			0.70%
Multi-currency revolving credit facility due 2021 | CDOR / LIBOR / EURIBOR / Bankers Acceptance Stamping Fee | Maximum
Debt Instrument [Line Items]
Variable rate spread			1.10%
Multi-currency revolving credit facility due 2021 | Alternate base rate and Canadian prime rate | Minimum
Debt Instrument [Line Items]
Variable rate spread			0.00%
Multi-currency revolving credit facility due 2021 | Alternate base rate and Canadian prime rate | Maximum
Debt Instrument [Line Items]
Variable rate spread			0.10%
Commercial paper
Debt Instrument [Line Items]
Maximum borrowing capacity								1,400,000,000
Debt instrument, term			365 days
Amount outstanding								0
Receivables securitization facility due 2019
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
Debt Instrument [Line Items]
Maximum borrowing capacity | £							£ 30,000,000
February 2015 Term Loan
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 1,000,000,000
Repayments of long-term debt						$ 725,000,000
February 2015 Term Loan | LIBOR
Debt Instrument [Line Items]
Variable rate spread			1.00%
February 2015 Term Loan | LIBOR | Minimum
Debt Instrument [Line Items]
Variable rate spread		0.75%
February 2015 Term Loan | LIBOR | Maximum
Debt Instrument [Line Items]
Variable rate spread		1.25%
February 2015 Term Loan | Base rate | Minimum
Debt Instrument [Line Items]
Variable rate spread		0.00%
February 2015 Term Loan | Base rate | Maximum
Debt Instrument [Line Items]
Variable rate spread		0.25%
November 2015 Term Loan
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 1,000,000,000
Repayments of long-term debt					$ 650,000,000
November 2015 Term Loan | LIBOR
Debt Instrument [Line Items]
Variable rate spread			1.00%
November 2015 Term Loan | LIBOR | Minimum
Debt Instrument [Line Items]
Variable rate spread	0.75%
November 2015 Term Loan | LIBOR | Maximum
Debt Instrument [Line Items]
Variable rate spread	1.25%
November 2015 Term Loan | Base rate | Minimum
Debt Instrument [Line Items]
Variable rate spread	0.00%
November 2015 Term Loan | Base rate | Maximum
Debt Instrument [Line Items]
Variable rate spread	0.25%

Stockholders' Equity and Earn35

Stockholders' Equity and Earnings per Share - Additional Information (Details) - USD ($) $ / shares in Units, shares in Millions	1 Months Ended	3 Months Ended			6 Months Ended
	Nov. 30, 2016	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016	May 31, 2016
Equity, Class of Treasury Stock [Line Items]
Percentage increase of cash dividend	7.00%
Cash dividends declared per share of common stock (usd per share)		$ 0.365	$ 0.34	$ 0.34	$ 0.73	$ 0.68
Authorized amount under share repurchase program							$ 750,000,000
Antidilutive securities excluded from earnings per share computation (shares)		3.8		2.3	4.6	1.9
May 2016 Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Repurchase of common stock (shares)			2.1
Settlement of accelerated share repurchase transaction (shares)			0.5
Repurchase of common stock			$ 118,800,000
November 2016 Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Authorized amount under share repurchase program	$ 1,000,000,000
Repurchase of common stock (shares)					1.4
Repurchase of common stock					$ 111,100,000
Remaining availability under share repurchase program		$ 888,900,000			$ 888,900,000

Stockholders' Equity and Earn36

Stockholders' Equity and Earnings per Share - Weighted Average Number of Common Shares Outstanding (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Equity [Abstract]
Weighted average common shares outstanding - basic (shares)	217,650	207,858	218,166	207,017
Dilutive effect of stock options, restricted stock, and restricted stock units (shares)	3,571	3,421	3,445	3,639
Dilutive effect of Warrants (shares)	0	14,171	0	15,426
Weighted average common shares outstanding - diluted (shares)	221,221	225,450	221,611	226,082

Related Party Transactions (Det

Related Party Transactions (Details) - Investor - Walgreens Boots Alliance, Inc. - USD ($) $ in Billions	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016	Sep. 30, 2016
Related Party Transaction [Line Items]
Ownership percentage (more than)	10.00%		10.00%
Revenue from related party	$ 11	$ 10.7	$ 22.2	$ 21.7
Receivable from related party	$ 4.6		$ 4.6		$ 4

Legal Matters and Contingenci38

Legal Matters and Contingencies (Details) $ in Millions	Jan. 09, 2017USD ($)	Apr. 01, 2016USD ($)claim	Sep. 10, 2014USD ($)	Mar. 31, 2017USD ($)amendmentplaintiff
West Virginia AG
Loss Contingencies [Line Items]
Damages awarded to (against)	$ (16)
PMC Litigation | Unpaid Invoices
Loss Contingencies [Line Items]
Damages awarded to (against)		$ 48.6
Gain contingency, damages sought (nearly)				$ 50
Gain contingency, number of counterclaims settled | claim		1
PMC Litigation | Unpaid Rebates
Loss Contingencies [Line Items]
Loss contingency, damages sought (in excess of)			$ 8	$ 33
Loss contingency, number of amendments | amendment				3
PMC Litigation | Additional Breaches and Damages
Loss Contingencies [Line Items]
Loss contingency, damages sought (in excess of)				$ 100
Kermit and Welch | Threatened litigation | West Virginia AG
Loss Contingencies [Line Items]
Loss contingency, number of plaintiffs | plaintiff				2
Boone, Cabell, Fayette, Kanawha, Logan, Wayne and Wyoming Counties | Threatened litigation | West Virginia AG
Loss Contingencies [Line Items]
Loss contingency, number of plaintiffs | plaintiff				7

Litigation Settlements (Details

Litigation Settlements (Details) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Litigation Settlement [Abstract]
Gain related to litigation settlement	$ 1.4	$ 12.8

Fair Value of Financial Instr40

Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2017	Sep. 30, 2016
Fixed-income securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized cost of investments	$ 119	$ 39.1
Estimate of Fair Value Measurement | Level 2 inputs
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	3,546.4	3,750.9
Estimate of Fair Value Measurement | Level 2 inputs | Fixed-income securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale securities	119	39.1
Reported Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	3,478.2	3,576.5
Money market | Estimate of Fair Value Measurement | Level 1 inputs
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	1,000	650
Cash and cash equivalents | Estimate of Fair Value Measurement | Level 2 inputs | Fixed-income securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale securities	$ 80.4	$ 13

Business Segment Information -

Business Segment Information - Segment Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 37,147,402	$ 35,698,357	$ 75,316,667	$ 72,407,403
Intersegment eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	(67,690)	(67,181)	(138,046)	(130,629)
Pharmaceutical Distribution Services | Operating segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	35,518,955	34,165,733	72,094,922	69,360,412
Other | Operating segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 1,696,137	$ 1,599,805	$ 3,359,791	$ 3,177,620

Business Segment Information 42

Business Segment Information - Segment Operating Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Total segment operating income	$ 624,981	$ 950,482	$ 1,024,968	$ 772,346
Operating segments
Segment Reporting Information [Line Items]
Total segment operating income	588,470	594,121	1,074,665	1,070,940
Intersegment eliminations
Segment Reporting Information [Line Items]
Total segment operating income	(1)	0	(14)	0
Pharmaceutical Distribution Services | Operating segments
Segment Reporting Information [Line Items]
Total segment operating income	482,265	500,165	856,267	881,419
Other | Operating segments
Segment Reporting Information [Line Items]
Total segment operating income	$ 106,206	$ 93,956	$ 218,412	$ 189,521

Business Segment Information 43

Business Segment Information - Reconciliation of Segment Operating Income to Income (Loss) from Operations before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Gain from antitrust litigation settlements			$ 1,400	$ 12,800
LIFO credit (expense)			58,196	(193,941)
Warrants income	$ 0	$ 503,946	0	36,571
Employee severance, litigation, and other	(11,934)	(17,617)	(33,000)	(36,485)
Pension settlement	0	1,124	0	(47,607)
Operating income	624,981	950,482	1,024,968	772,346
Other income	(5,233)	(756)	(5,356)	(1,066)
Interest expense, net	37,299	35,966	74,271	69,707
Income before income taxes	592,915	915,272	956,053	703,705
Operating segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income	588,470	594,121	1,074,665	1,070,940
Segment reconciling items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Gain from antitrust litigation settlements	0	7	1,395	12,798
LIFO credit (expense)	86,504	(92,379)	58,196	(193,941)
Acquisition-related intangibles amortization	(38,059)	(38,720)	(76,288)	(69,930)
Warrants income	0	503,946	0	36,571
Employee severance, litigation, and other	(11,934)	(17,617)	(33,000)	(36,485)
Pension settlement	$ 0	$ 1,124	$ 0	$ (47,607)