Equity method investments - summarized financial information of equity method investees (Details) - USD ($) $ in Millions	12 Months Ended
Aug. 31, 2019	Aug. 31, 2018	Aug. 31, 2017
Equity Method Investment, Summarized Financial Information [Abstract]
Current assets	$ 36,523	$ 34,493
Non-current assets	15,710	14,971
Current liabilities	35,857	34,055
Non-current liabilities	9,633	8,759
Shareholders’ equity	6,743	6,650
Income Statement [Abstract]
Sales	197,237	179,887	$ 164,844
Gross profit	7,516	6,875	5,958
Net earnings	1,037	1,315	1,040
Share of earnings from equity method investments	$ 187	$ 245	$ 143

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