Equity method investments - summarized financial information of equity method investees (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Aug. 31, 2021	May 31, 2021	Feb. 28, 2021	Nov. 30, 2020	Aug. 31, 2020	May 31, 2020	Feb. 29, 2020	Nov. 30, 2019	Aug. 31, 2021	Aug. 31, 2020	Aug. 31, 2019	Aug. 31, 2018
Statement of Financial Position [Abstract]
Current assets	$ 15,814				$ 18,073				$ 15,814	$ 18,073
Non-current assets	65,471				69,101				65,471	69,101
Current liabilities	22,054				27,070				22,054	27,070
Non-current liabilities	35,091				38,968				35,091	38,968
Shareholders' equity	23,822				21,136				23,822	21,136	$ 24,152	$ 26,689
Noncontrolling interests	402				498				402	498
Income Statement [Abstract]
Sales	34,262	$ 34,030	$ 32,779	$ 31,438	30,371	$ 30,364	$ 31,336	$ 29,912	132,509	121,982	120,074
Gross profit	7,503	$ 7,153	$ 6,781	$ 6,630	6,324	$ 5,959	$ 7,017	$ 6,777	28,067	26,078	28,159
Net earnings (loss)									2,512	424	3,962
Share of earnings (loss) from equity method investments									(512)	372	172
Equity Method Investment
Statement of Financial Position [Abstract]
Current assets	49,538				39,167				49,538	39,167
Non-current assets	27,442				18,138				27,442	18,138
Current liabilities	48,766				38,034				48,766	38,034
Non-current liabilities	22,046				10,600				22,046	10,600
Shareholders' equity	6,168				8,671				6,168	8,671
Noncontrolling interests	$ 646				$ 387				646	387
Income Statement [Abstract]
Sales									232,719	208,625	195,540
Gross profit									10,889	8,707	7,303
Net earnings (loss)									$ (3,475)	$ 1,624	$ 997