Supplemental information - Narrative (Details) - USD ($) shares in Millions, $ in Billions	3 Months Ended
	Nov. 30, 2022	Nov. 30, 2021	Aug. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable from related party	$ 1.2		$ 1.1
Accumulated depreciation and amortization on property, plant, and equipment	$ 12.9		12.8
Antidilutive securities excluded from EPS calculations (in shares)	19.3	16.1
Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements	2.6
Trade Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables	$ 3.7		$ 4.0