Financial instruments - derivative instruments (Details) - USD ($) $ in Millions	Aug. 31, 2020	Aug. 31, 2019
Cross currency interest rate swaps \| Derivatives designated as hedges: \| Other non-current assets
Derivatives, Fair Value [Line Items]
Notional amount, assets	$ 722	$ 800
Fair value, assets	16	73
Cross currency interest rate swaps \| Derivatives designated as hedges: \| Other current assets
Derivatives, Fair Value [Line Items]
Notional amount, assets	50
Fair value, assets	0
Cross currency interest rate swaps \| Derivatives designated as hedges: \| Other non-current liabilities
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	318
Fair value, liabilities	13
Cross currency interest rate swaps \| Derivatives designated as hedges: \| Other current liabilities
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	103
Fair value, liabilities	3
Interest rate swaps \| Derivatives designated as hedges: \| Other non-current liabilities
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	1,000
Fair value, liabilities	10
Foreign currency forwards \| Derivatives designated as hedges: \| Other current assets
Derivatives, Fair Value [Line Items]
Notional amount, assets	100	18
Fair value, assets	1	1
Foreign currency forwards \| Derivatives designated as hedges: \| Other non-current liabilities
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	49
Fair value, liabilities	1
Foreign currency forwards \| Derivatives designated as hedges: \| Other current liabilities
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	671
Fair value, liabilities	23
Foreign currency forwards \| Derivatives not designated as hedges: \| Other current assets
Derivatives, Fair Value [Line Items]
Notional amount, assets	1,930	3,485
Fair value, assets	19	87
Foreign currency forwards \| Derivatives not designated as hedges: \| Other current liabilities
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	2,934	707
Fair value, liabilities	56	$ 6
Total return swap \| Derivatives not designated as hedges: \| Other current liabilities
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	205
Fair value, liabilities	$ 1

Nominal or face amount used to calculate payments on the derivative asset.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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Nominal or face amount used to calculate payments on the derivative liability.

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No definition available.

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