Equity method investments - Summarized Financial Information of Equity Method Investments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	May 31, 2021	May 31, 2020	May 31, 2021	May 31, 2020
Income Statement [Abstract]
Sales	$ 34,030	$ 30,364	$ 98,247	$ 91,612
Gross profit	7,153	5,959	20,564	19,753
Net earnings (loss)	1,173	(1,726)	1,899	68
Share of earnings (loss) from equity method investments	672	249	(591)	289
Equity Method Investment
Income Statement [Abstract]
Sales	55,890	52,772	171,417	157,382
Gross profit	2,558	2,253	7,647	6,476
Net earnings (loss)	$ 489	$ 912	$ (3,841)	$ 1,268