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Financial instruments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
Financial instruments (Details) - USD ($) $ in Millions	Feb. 28, 2022	Feb. 28, 2021	Feb. 28, 2022	Feb. 28, 2021	Aug. 31, 2021
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	$ (51)	$ (95)	$ 4	$ (124)
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	0	7	(1)	(1)
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	(8)	$ 16	(10)	$ 29
Other current assets \| Foreign currency forwards \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, assets	115		115		$ 575
Fair value, assets	3		3		7
Other current assets \| Foreign currency forwards \| Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, assets	1,865		1,865		3,636
Fair value, assets	9		9		38
Other current assets \| Total return swap \| Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, assets	104		104		224
Fair value, assets	1		1		2
Other non-current assets \| Foreign currency forwards \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, assets	4		4		6
Fair value, assets	0		0		0
Other non-current assets \| Cross currency interest rate swaps \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, assets	155		155		155
Fair value, assets	1		1		1
Other current liabilities \| Foreign currency forwards \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	569		569		31
Fair value, liabilities	5		5		1
Other current liabilities \| Foreign currency forwards \| Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	2,797		2,797		808
Fair value, liabilities	18		18		3
Other current liabilities \| Cross currency interest rate swaps \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	159		159		109
Fair value, liabilities	7		7		9
Other current liabilities \| Total return swap \| Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	150		150		37
Fair value, liabilities	1		1		0
Other non-current liabilities \| Foreign currency forwards \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	12		12		23
Fair value, liabilities	0		0		1
Other non-current liabilities \| Cross currency interest rate swaps \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	640		640		801
Fair value, liabilities	$ 18		$ 18		$ 23