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Financial instruments (Details) - USD ($) $ in Millions	3 Months Ended
Financial instruments (Details) - USD ($) $ in Millions	Nov. 30, 2020	Nov. 30, 2019	Aug. 31, 2020
Foreign currency forwards \| Not Designated as Hedging Instrument \| Selling, general and administrative expenses
Derivatives, Fair Value [Line Items]
Gains and (losses) due to changes in fair value of derivative instruments	$ (29)	$ (74)
Foreign currency forwards \| Not Designated as Hedging Instrument \| Other income (expense)
Derivatives, Fair Value [Line Items]
Gains and (losses) due to changes in fair value of derivative instruments	(9)	11
Total return swap \| Not Designated as Hedging Instrument \| Selling, general and administrative expenses
Derivatives, Fair Value [Line Items]
Gains and (losses) due to changes in fair value of derivative instruments	13	$ 0
Other non-current assets \| Cross currency interest rate swaps \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, assets	674		$ 722
Fair value, assets	9		16
Other current assets \| Cross currency interest rate swaps \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, assets			50
Fair value, assets			0
Other current assets \| Foreign currency forwards \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, assets	100		100
Fair value, assets	1		1
Other current assets \| Foreign currency forwards \| Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, assets	1,729		1,930
Fair value, assets	15		19
Other non-current liabilities \| Cross currency interest rate swaps \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	264		318
Fair value, liabilities	8		13
Other non-current liabilities \| Foreign currency forwards \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	46		49
Fair value, liabilities	1		1
Other non-current liabilities \| Interest rate swaps \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	1,000		1,000
Fair value, liabilities	6		10
Other current liabilities \| Cross currency interest rate swaps \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	157		103
Fair value, liabilities	7		3
Other current liabilities \| Foreign currency forwards \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	781		671
Fair value, liabilities	11		23
Other current liabilities \| Foreign currency forwards \| Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	2,677		2,934
Fair value, liabilities	50		56
Other current liabilities \| Total return swap \| Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	219		205
Fair value, liabilities	$ 1		$ 1