Financial instruments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	May 31, 2021	May 31, 2020	May 31, 2021	May 31, 2020	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	$ (53)	$ 72	$ (177)	$ 11
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	(5)	2	(6)	6
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	20	$ 5	48	$ 5
Other non-current assets | Interest rate swaps | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, assets	1,000		1,000
Fair value, assets	5		5
Other non-current assets | Cross currency interest rate swaps | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, assets					$ 722
Fair value, assets					16
Other current assets | Foreign currency forwards | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, assets	1		1		100
Fair value, assets	0		0		1
Other current assets | Foreign currency forwards | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, assets	1,368		1,368		1,930
Fair value, assets	3		3		19
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 | Total return swap | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, assets	244		244
Fair value, assets	9		9
Other non-current liabilities | Interest rate swaps | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities					1,000
Fair value, liabilities					10
Other non-current liabilities | Foreign currency forwards | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	39		39		49
Fair value, liabilities	2		2		1
Other non-current liabilities | Cross currency interest rate swaps | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	992		992		318
Fair value, liabilities	58		58		13
Other current liabilities | Foreign currency forwards | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	635		635		671
Fair value, liabilities	14		14		23
Other current liabilities | Foreign currency forwards | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	2,613		2,613		2,934
Fair value, liabilities	30		30		56
Other current liabilities | Cross currency interest rate swaps | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities	113		113		103
Fair value, liabilities	$ 13		$ 13		3
Other current liabilities | Total return swap | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount, liabilities					205
Fair value, liabilities					$ 1