Fair value measurements (Details) $ in Millions	Aug. 31, 2023 USD ($)	Aug. 31, 2022 USD ($)
Liabilities [Abstract]
Carrying value of long-term notes outstanding	$ 9,092
Carrying Value
Liabilities [Abstract]
Carrying value of long-term notes outstanding	7,700
Estimate of Fair Value Measurement
Liabilities [Abstract]
Fair value of long-term notes outstanding	$ 6,800
Level 3 | Measurement Input, Price Volatility | Minimum | Lower Strike Price
Liabilities [Abstract]
Derivative liability, measurement input	0.232
Level 3 | Measurement Input, Price Volatility | Minimum | Upper Strike Price
Liabilities [Abstract]
Derivative liability, measurement input	0.181
Level 3 | Measurement Input, Price Volatility | Maximum | Lower Strike Price
Liabilities [Abstract]
Derivative liability, measurement input	0.247
Level 3 | Measurement Input, Price Volatility | Maximum | Upper Strike Price
Liabilities [Abstract]
Derivative liability, measurement input	0.191
Recurring
Assets [Abstract]
Money market funds	$ 11	$ 1,114
Investment in equity securities	17	1
Investments in debt securities	15	130
Recurring | Level 1
Assets [Abstract]
Money market funds	11	1,114
Investment in equity securities	17	1
Investments in debt securities	0	0
Recurring | Level 2
Assets [Abstract]
Money market funds	0	0
Investment in equity securities	0	0
Investments in debt securities	15	130
Recurring | Level 3
Assets [Abstract]
Money market funds	0	0
Investment in equity securities	0	0
Investments in debt securities	0	0
Recurring | Foreign currency forwards
Assets [Abstract]
Derivative asset	6	69
Liabilities [Abstract]
Derivative liability	5	7
Recurring | Foreign currency forwards | Level 1
Assets [Abstract]
Derivative asset	0	0
Liabilities [Abstract]
Derivative liability	0	0
Recurring | Foreign currency forwards | Level 2
Assets [Abstract]
Derivative asset	6	69
Liabilities [Abstract]
Derivative liability	5	7
Recurring | Foreign currency forwards | Level 3
Assets [Abstract]
Derivative asset	0	0
Liabilities [Abstract]
Derivative liability	0	0
Recurring | Cross currency interest rate swaps
Assets [Abstract]
Derivative asset	28	96
Liabilities [Abstract]
Derivative liability	2
Recurring | Cross currency interest rate swaps | Level 1
Assets [Abstract]
Derivative asset	0	0
Liabilities [Abstract]
Derivative liability	0
Recurring | Cross currency interest rate swaps | Level 2
Assets [Abstract]
Derivative asset	28	96
Liabilities [Abstract]
Derivative liability	2
Recurring | Cross currency interest rate swaps | Level 3
Assets [Abstract]
Derivative asset	0	0
Liabilities [Abstract]
Derivative liability	0
Recurring | Total return swaps
Assets [Abstract]
Derivative asset	1
Liabilities [Abstract]
Derivative liability	1	6
Recurring | Total return swaps | Level 1
Assets [Abstract]
Derivative asset	0
Liabilities [Abstract]
Derivative liability	0	0
Recurring | Total return swaps | Level 2
Assets [Abstract]
Derivative asset	1
Liabilities [Abstract]
Derivative liability	1	6
Recurring | Total return swaps | Level 3
Assets [Abstract]
Derivative asset	0
Liabilities [Abstract]
Derivative liability	0	$ 0
Recurring | Variable prepaid forward
Liabilities [Abstract]
Derivative liability	2,548
Recurring | Variable prepaid forward | Level 1
Liabilities [Abstract]
Derivative liability	0
Recurring | Variable prepaid forward | Level 2
Liabilities [Abstract]
Derivative liability	0
Recurring | Variable prepaid forward | Level 3
Liabilities [Abstract]
Derivative liability	$ 2,548