Goodwill and other intangible assets - Schedule of Finite-Lived Intangible Assets by Major Class (Details) - USD ($) $ in Millions	Feb. 28, 2023	Aug. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	$ 10,373	$ 7,155
Accumulated amortization	2,136	1,953
Total amortizable intangible assets, net	8,237	5,202
Indefinite-lived intangible assets	5,628	5,528
Total intangible assets, net	13,864	10,730
Trade names and trademarks
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	4,397	4,319
Pharmacy licenses
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	1,231	1,209
Customer relationships and loyalty card holders
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	4,466	4,619
Accumulated amortization	1,574	1,548
Provider networks
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	3,099	1,247
Accumulated amortization	126	64
Trade names and trademarks
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	2,271	760
Accumulated amortization	301	246
Developed technology
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	442	436
Accumulated amortization	92	56
Others
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	95	93
Accumulated amortization	$ 43	$ 39