Goodwill and other intangible assets - Schedule of Finite-Lived Intangible Assets by Major Class (Details) - USD ($) $ in Millions	Nov. 30, 2022	Aug. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	$ 7,015	$ 7,155
Accumulated amortization	1,960	1,953
Total amortizable intangible assets, net	5,055	5,202
Indefinite-lived intangible assets	5,557	5,528
Total intangible assets, net	10,612	10,730
Trade names and trademarks
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	4,342	4,319
Pharmacy licenses
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	1,215	1,209
Customer relationships and loyalty card holders
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	4,470	4,619
Accumulated amortization	1,497	1,548
Primary care provider network
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	1,247	1,247
Accumulated amortization	84	64
Trade names and trademarks
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	768	760
Accumulated amortization	263	246
Developed technology
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	435	436
Accumulated amortization	74	56
Purchasing and payor contracts
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	15	15
Accumulated amortization	4	4
Others
Finite-Lived Intangible Assets [Line Items]
Gross amortizable intangible assets	80	78
Accumulated amortization	$ 37	$ 35