Segment reporting (Details) $ in Millions	3 Months Ended		9 Months Ended
	May 31, 2023 USD ($)	May 31, 2022 USD ($)	May 31, 2023 USD ($) segment	May 31, 2022 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment			3
Segment Reporting Information [Line Items]
Sales	$ 35,415	$ 32,597	$ 103,659	$ 100,254
Adjusted operating income (Non-GAAP measure)	959	955	3,188	4,389
Certain legal and regulatory accruals and settlements	(268)	(734)	(7,249)	(734)
Acquisition-related amortization	(274)	(201)	(851)	(616)
Acquisition-related costs	(70)	(40)	(257)	(155)
Transformational cost management	(414)	(185)	(697)	(458)
Adjustments to equity earnings in AmerisourceBergen	(61)	(60)	(178)	(155)
LIFO provision	(51)	(55)	(89)	(64)
Impairment of intangible assets	(299)	0	(299)	0
Operating (loss) income	(477)	(320)	(6,431)	2,209
Reportable Segments | U.S. Retail Pharmacy
Segment Reporting Information [Line Items]
Sales	27,866	26,695	82,648	82,394
Adjusted operating income (Non-GAAP measure)	962	966	3,134	4,243
Reportable Segments | International
Segment Reporting Information [Line Items]
Sales	5,573	5,305	16,414	16,686
Adjusted operating income (Non-GAAP measure)	208	174	676	563
Reportable Segments | U.S. Healthcare
Segment Reporting Information [Line Items]
Sales	1,975	596	4,597	1,173
Adjusted operating income (Non-GAAP measure)	(172)	(129)	(483)	(218)
Corporate and Other
Segment Reporting Information [Line Items]
Sales	0	1	0	0
Adjusted operating income (Non-GAAP measure)	$ (39)	$ (56)	$ (139)	$ (198)