Segment reporting (Details) $ in Millions	3 Months Ended	9 Months Ended
May 31, 2022 USD ($)	May 31, 2021 USD ($)	May 31, 2022 USD ($) segment	May 31, 2021 USD ($)
Segment Reporting [Abstract]
Number of reportable segments \| segment			3
Segment Reporting Information [Line Items]
Sales	$ 32,597	$ 34,030	$ 100,254	$ 98,247
Adjusted operating income	955	1,459	4,389	3,881
Adjustments to equity earnings (loss) in AmerisourceBergen	(60)	(48)	(155)	(1,575)
Transformational cost management	(185)	(60)	(458)	(338)
Acquisition-related amortization	(201)	(158)	(616)	(367)
Certain legal and regulatory accruals and settlements	(734)	0	(734)	(60)
LIFO provision	(55)	(51)	(64)	(85)
Acquisition-related costs	(40)	(9)	(155)	(25)
Operating (loss) income	(320)	1,134	2,209	1,432
Reportable Segments \| United States
Segment Reporting Information [Line Items]
Sales	26,695	28,743	82,394	83,250
Adjusted operating income	966	1,471	4,243	3,789
Reportable Segments \| International
Segment Reporting Information [Line Items]
Sales	5,305	5,288	16,686	14,998
Adjusted operating income	174	94	563	326
Reportable Segments \| Walgreens Health
Segment Reporting Information [Line Items]
Sales	596	0	1,173	0
Adjusted operating income	(129)	(17)	(218)	(31)
Corporate and Other
Segment Reporting Information [Line Items]
Sales	1	0	0	0
Adjusted operating income	$ (56)	$ (88)	$ (198)	$ (202)

The amount of expense recognized in the current period that reflects the allocation of capitalized costs associated with acquisition of business. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

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Amount of gain (loss) recognized in settlement of litigation and insurance claims. Excludes claims within an insurance entity's normal claims settlement process.

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The change in the inventory reserve representing the cumulative difference in cost between the first in, first out and the last in, first out inventory valuation methods, which change has been reflected in the statement of income during the period.

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Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

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The net result for the period of deducting operating expenses from operating revenues.

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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The total amount of adjusted operating income, the components of which are not separately disclosed on the income statement, from items that are associated with the entity's normal revenue producing operation.

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