Equity method investments - carrying value (Details) - USD ($) $ in Millions	Aug. 31, 2023	Aug. 31, 2022
Schedule of Equity Method Investments [Line Items]
Carrying value	$ 3,497	$ 5,495
Cencora
Schedule of Equity Method Investments [Line Items]
Carrying value	$ 2,534	$ 3,916
Ownership percentage	16.00%	25.00%
Others
Schedule of Equity Method Investments [Line Items]
Carrying value	$ 963	$ 1,579
Others | Minimum
Schedule of Equity Method Investments [Line Items]
Ownership percentage	8.00%	8.00%
Others | Maximum
Schedule of Equity Method Investments [Line Items]
Ownership percentage	50.00%	50.00%