Segment reporting (Details) $ in Millions	3 Months Ended		6 Months Ended
	Feb. 28, 2023 USD ($)	Feb. 28, 2022 USD ($)	Feb. 28, 2023 USD ($) segment	Feb. 28, 2022 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment			3
Segment Reporting Information [Line Items]
Sales	$ 34,862	$ 33,756	$ 68,244	$ 67,656
Adjusted operating income (Non-GAAP measure)	1,215	1,657	2,229	3,434
Certain legal and regulatory accruals and settlements	(427)	0	(6,981)	0
Acquisition-related amortization	(247)	(250)	(577)	(415)
Acquisition-related costs	(148)	(44)	(187)	(115)
Transformational cost management	(145)	(70)	(283)	(273)
Adjustments to equity earnings in AmerisourceBergen	(31)	(51)	(117)	(94)
LIFO provision	(20)	5	(38)	(9)
Operating income (loss)	197	1,246	(5,954)	2,529
Reportable Segments | U.S. Retail Pharmacy
Segment Reporting Information [Line Items]
Sales	27,577	27,667	54,781	55,699
Adjusted operating income (Non-GAAP measure)	1,067	1,588	2,172	3,277
Reportable Segments | International
Segment Reporting Information [Line Items]
Sales	5,651	5,563	10,840	11,381
Adjusted operating income (Non-GAAP measure)	352	226	468	389
Reportable Segments | U.S. Healthcare
Segment Reporting Information [Line Items]
Sales	1,634	527	2,622	577
Adjusted operating income (Non-GAAP measure)	(159)	(77)	(311)	(90)
Corporate and Other
Segment Reporting Information [Line Items]
Sales	0	(1)	0	(1)
Adjusted operating income (Non-GAAP measure)	$ (44)	$ (79)	$ (100)	$ (143)