Fair value measurements (Details) - USD ($) $ in Millions	May 31, 2023	Aug. 31, 2022
Carrying Value
Liabilities [Abstract]
Fair value of long-term notes outstanding	$ 7,700
Estimate of Fair Value Measurement
Liabilities [Abstract]
Carrying value of long-term notes outstanding	6,900
Recurring
Assets [Abstract]
Money market funds	99	$ 1,114
Investments in equity securities	315	1
Investments in debt securities	21	130
Level 1 | Recurring
Assets [Abstract]
Money market funds	99	1,114
Investments in equity securities	315	1
Investments in debt securities	0	0
Level 2 | Recurring
Assets [Abstract]
Money market funds	0	0
Investments in equity securities	0	0
Investments in debt securities	21	130
Level 3 | Recurring
Assets [Abstract]
Money market funds	0	0
Investments in equity securities	0	0
Investments in debt securities	0	0
Foreign currency forwards | Recurring
Assets [Abstract]
Derivative asset	16	69
Liabilities [Abstract]
Derivative liability	19	7
Foreign currency forwards | Level 1 | Recurring
Assets [Abstract]
Derivative asset	0	0
Liabilities [Abstract]
Derivative liability	0	0
Foreign currency forwards | Level 2 | Recurring
Assets [Abstract]
Derivative asset	16	69
Liabilities [Abstract]
Derivative liability	19	7
Foreign currency forwards | Level 3 | Recurring
Assets [Abstract]
Derivative asset	0	0
Liabilities [Abstract]
Derivative liability	0	0
Cross currency interest rate swaps | Recurring
Assets [Abstract]
Derivative asset	44	96
Cross currency interest rate swaps | Level 1 | Recurring
Assets [Abstract]
Derivative asset	0	0
Cross currency interest rate swaps | Level 2 | Recurring
Assets [Abstract]
Derivative asset	44	96
Cross currency interest rate swaps | Level 3 | Recurring
Assets [Abstract]
Derivative asset	0	0
Total return swap | Recurring
Assets [Abstract]
Derivative asset	1
Liabilities [Abstract]
Derivative liability	1	6
Total return swap | Level 1 | Recurring
Assets [Abstract]
Derivative asset	0
Liabilities [Abstract]
Derivative liability	0	0
Total return swap | Level 2 | Recurring
Assets [Abstract]
Derivative asset	1
Liabilities [Abstract]
Derivative liability	1	6
Total return swap | Level 3 | Recurring
Assets [Abstract]
Derivative asset	0
Liabilities [Abstract]
Derivative liability	0	$ 0
Variable prepaid forward | Recurring
Liabilities [Abstract]
Derivative liability	670
Variable prepaid forward | Level 1 | Recurring
Liabilities [Abstract]
Derivative liability	0
Variable prepaid forward | Level 2 | Recurring
Liabilities [Abstract]
Derivative liability	0
Variable prepaid forward | Level 3 | Recurring
Liabilities [Abstract]
Derivative liability	$ 670