Goodwill and other intangible assets - Schedule of Finite-Lived Intangible Assets by Major Class (Details) - USD ($) $ in Millions	Feb. 29, 2024	Aug. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	$ 10,518	$ 10,767
Accumulated amortization	2,964	2,609
Total amortizable intangible assets, net	7,554	8,158
Indefinite-lived intangible assets	5,430	5,477
Total intangible assets, net	12,984	13,635
Trade names and trademarks
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	4,609	4,650
Pharmacy licenses
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	821	828
Customer relationships and loyalty card holders
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	4,671	4,658
Accumulated amortization	1,920	1,784
Provider networks
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	2,966	3,202
Accumulated amortization	325	233
Trade names and trademarks
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	2,298	2,300
Accumulated amortization	482	401
Developed technology
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	469	469
Accumulated amortization	182	143
Others
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	113	137
Accumulated amortization	$ 55	$ 48