Supplemental information - Narrative (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Feb. 28, 2021	Feb. 29, 2020	Aug. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable from related party	$ 1,400		$ 1,100
Accumulated depreciation and amortization on property, plant, and equipment	12,700		12,100
Redeemable noncontrolling interest	$ 309		0
Antidilutive securities excluded from EPS calculations (in shares)	17.1	18.7
Trade Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables	$ 3,500		$ 3,000