Fair value measurements (Details) - USD ($) $ in Millions	Nov. 30, 2020	Aug. 31, 2020
Recurring
Assets [Abstract]
Money market funds	$ 309	$ 6
Investments in equity securities	13	1
Investments in debt securities	20
Recurring \| Level 1
Assets [Abstract]
Money market funds	309	6
Investments in equity securities	13	1
Investments in debt securities	0
Recurring \| Level 2
Assets [Abstract]
Money market funds	0	0
Investments in equity securities	0	0
Investments in debt securities	0
Recurring \| Level 3
Assets [Abstract]
Money market funds	0	0
Investments in equity securities	0	0
Investments in debt securities	20
Recurring \| Foreign currency forwards
Assets [Abstract]
Derivative asset	16	20
Liabilities [Abstract]
Derivative liability	62	80
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	16	20
Liabilities [Abstract]
Derivative liability	62	80
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	9	16
Liabilities [Abstract]
Derivative liability	15	16
Recurring \| Cross currency interest rate swaps \| Level 1
Assets [Abstract]
Derivative asset	0	0
Liabilities [Abstract]
Derivative liability	0	0
Recurring \| Cross currency interest rate swaps \| Level 2
Assets [Abstract]
Derivative asset	9	16
Liabilities [Abstract]
Derivative liability	15	16
Recurring \| Cross currency interest rate swaps \| Level 3
Assets [Abstract]
Derivative asset	0	0
Liabilities [Abstract]
Derivative liability	0	0
Recurring \| Warrants
Assets [Abstract]
Derivative asset	3
Recurring \| Warrants \| Level 1
Assets [Abstract]
Derivative asset	0
Recurring \| Warrants \| Level 2
Assets [Abstract]
Derivative asset	3
Recurring \| Warrants \| Level 3
Assets [Abstract]
Derivative asset	0
Recurring \| Interest rate swaps
Liabilities [Abstract]
Derivative liability	6	10
Recurring \| Interest rate swaps \| Level 1
Liabilities [Abstract]
Derivative liability	0	0
Recurring \| Interest rate swaps \| Level 2
Liabilities [Abstract]
Derivative liability	6	10
Recurring \| Interest rate swaps \| Level 3
Liabilities [Abstract]
Derivative liability	0	0
Recurring \| Total return swap
Liabilities [Abstract]
Derivative liability	1	1
Recurring \| Total return swap \| Level 1
Liabilities [Abstract]
Derivative liability	0	0
Recurring \| Total return swap \| Level 2
Liabilities [Abstract]
Derivative liability	1	1
Recurring \| Total return swap \| Level 3
Liabilities [Abstract]
Derivative liability	0	$ 0
Carrying Value
Liabilities [Abstract]
Fair value of long-term notes outstanding	13,400
Estimate of Fair Value Measurement
Liabilities [Abstract]
Carrying value of long-term notes outstanding	$ 12,200

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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