Segment reporting (Details) $ in Millions	3 Months Ended	6 Months Ended
Feb. 28, 2022 USD ($)	Feb. 28, 2021 USD ($)	Feb. 28, 2022 USD ($) segment	Feb. 28, 2021 USD ($)
Segment Reporting [Abstract]
Number of reportable segments \| segment			3
Segment Reporting Information [Line Items]
Sales	$ 33,756	$ 32,779	$ 67,656	$ 64,217
Adjusted operating income	1,657	1,225	3,434	2,422
Adjustments to equity earnings (loss) in AmerisourceBergen	(51)	(45)	(94)	(1,526)
Transformational cost management	(70)	(178)	(273)	(278)
Acquisition-related amortization	(250)	(114)	(415)	(209)
Certain legal and regulatory accruals and settlements	0	(60)	0	(60)
LIFO provision	5	(2)	(9)	(35)
Acquisition-related costs	(44)	5	(115)	(16)
Operating income	1,246	832	2,529	298
Reportable Segments \| United States
Segment Reporting Information [Line Items]
Sales	27,667	27,344	55,699	54,507
Adjusted operating income	1,588	1,163	3,277	2,318
Reportable Segments \| International
Segment Reporting Information [Line Items]
Sales	5,563	5,425	11,381	9,709
Adjusted operating income	226	146	389	232
Reportable Segments \| Walgreens Health
Segment Reporting Information [Line Items]
Sales	527	0	577	0
Adjusted operating income	(77)	(11)	(90)	(14)
Corporate and Other
Segment Reporting Information [Line Items]
Sales	(1)	10	(1)	0
Adjusted operating income	$ (79)	$ (72)	$ (143)	$ (114)

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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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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