Goodwill and other intangible assets - Schedule of Finite-Lived Intangible Assets by Major Class (Details) - USD ($) $ in Millions	Nov. 30, 2023	Aug. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	$ 10,656	$ 10,767
Accumulated amortization	2,759	2,609
Total amortizable intangible assets, net	7,898	8,158
Indefinite-lived intangible assets	5,380	5,477
Total intangible assets, net	13,278	13,635
Trade names and trademarks
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	4,566	4,650
Pharmacy licenses
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	813	828
Customer relationships and loyalty card holders
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	4,630	4,658
Accumulated amortization	1,825	1,784
Provider networks
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	3,148	3,202
Accumulated amortization	281	233
Trade names and trademarks
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	2,296	2,300
Accumulated amortization	439	401
Developed technology
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	469	469
Accumulated amortization	162	143
Others
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	113	137
Accumulated amortization	$ 52	$ 48