Segment reporting - geographic data (Details) - USD ($) $ in Millions	12 Months Ended
	Aug. 31, 2024	Aug. 31, 2023	Aug. 31, 2022
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales	$ 147,658	$ 139,081	$ 132,703
Total long-lived assets	30,108	33,254
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales	124,176	116,883	110,873
Total long-lived assets	25,873	28,951
Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales	12,067	11,211	11,178
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales	9,550	8,984	8,894
Total long-lived assets	3,538	3,622
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales	1,864	2,003	$ 1,757
Total long-lived assets	$ 697	$ 681