Summary of major accounting policies - reconciliation of cash, cash equivalents and restricted cash (Details) - USD ($) $ in Millions	Aug. 31, 2023	Aug. 31, 2022	Aug. 31, 2021	Aug. 31, 2020
Accounting Policies [Abstract]
Cash and cash equivalents	$ 728	$ 1,358	$ 559
Marketable securities	11	1,114	634
Cash and cash equivalents - assets held for sale (included in other current assets)	24	0	0
Restricted cash (included in other current and non-current assets)	93	86	77
Cash, cash equivalents, marketable securities and restricted cash	$ 856	$ 2,558	$ 1,270	$ 746

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Amount of assets held-for-sale that are not part of a disposal group.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes 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. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References

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Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage. Excludes amount for disposal group and discontinued operations. 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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Amount of investment in marketable security, classified as current.

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Amount of cash and cash equivalents restricted as to withdrawal or usage, classified as current. 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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