Supplemental information - Summary of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Millions	Feb. 28, 2023	Aug. 31, 2022	Feb. 28, 2022	Aug. 31, 2021
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents	$ 1,088	$ 1,358
Marketable securities	752	1,114
Restricted cash	153	86
Cash, cash equivalents, marketable securities and restricted cash	$ 1,993	$ 2,558	$ 2,027	$ 1,270

Amount of cash and cash equivalents restricted as to withdrawal or usage. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant