Acquisition and Assets and Liabilities Held for Sale - Assets And Liabilities (Details) - USD ($) $ in Thousands		12 Months Ended
	Jun. 01, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Goodwill		$ 9,030,531	$ 6,706,719	$ 6,705,507
Net cash paid		$ 5,563,040	$ 0	$ 63,951
WBA Alliance Healthcare
Business Acquisition [Line Items]
Cash	$ 6,602,020
Equity (2 million shares of AmerisourceBergen Corporation common stock)	229,080
Estimated accrued consideration	96,851
Other equity consideration	6,061
Fair value of total consideration	6,934,012
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Cash and cash equivalents	921,995
Accounts receivable	3,703,895
Inventories	1,649,855
Prepaid expenses and other	381,926
Property and equipment	634,220
Goodwill	2,469,152
Other intangible assets	3,735,000
Other assets	550,855
Total assets acquired	14,046,898
Accounts payable	(4,618,807)
Accrued expenses and other	(765,463)
Short-term debt	(353,420)
Deferred income taxes	(791,600)
Other liabilities	(405,332)
Total liabilities assumed	(6,934,622)
Net assets acquired	7,112,276
Noncontrolling interest	(178,264)
Equity consideration	(235,141)
Estimated accrued consideration	(96,851)
Cash acquired, including restricted cash of $143,308 included in Prepaid Expenses and Other	(1,065,303)
Net cash paid	$ 5,536,717
Equity issued (shares)	2,000,000
Restricted cash acquired	$ 143,308