Equity method investments - Schedule of Equity Method Investments (Details) - USD ($) $ in Millions	Jun. 01, 2021	May 31, 2021	Aug. 31, 2020
Schedule of Equity Method Investments [Line Items]
Carrying value of equity method investments		$ 6,778	$ 7,204
AmerisourceBergen
Schedule of Equity Method Investments [Line Items]
Carrying value of equity method investments		$ 4,193	$ 5,446
Ownership percentage	28.40%	27.70%	27.70%
Others
Schedule of Equity Method Investments [Line Items]
Carrying value of equity method investments		$ 2,584	$ 1,758
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%
Total
Schedule of Equity Method Investments [Line Items]
Carrying value of equity method investments		$ 6,778	$ 7,204