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Goodwill and other intangible assets - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Nov. 30, 2021	Nov. 30, 2020	Aug. 31, 2021	Jun. 01, 2021
Goodwill [Line Items]
Goodwill	$ 21,520		$ 12,421
Indefinite-lived intangible assets	7,244		7,342
Amortization of intangible assets	165	$ 95
Minimum
Goodwill [Line Items]
Reporting unit fair value in excess of carrying amount (as a percent)				18.00%
Maximum
Goodwill [Line Items]
Reporting unit fair value in excess of carrying amount (as a percent)				195.00%
Other International Reporting Unit
Goodwill [Line Items]
Reporting unit fair value in excess of carrying amount (as a percent)				29.00%
Goodwill	372
Boots Reporting Unit
Goodwill [Line Items]
Goodwill	1,000
Indefinite-lived intangible assets	$ 7,200		$ 7,300
Boots Reporting Unit \| Minimum
Goodwill [Line Items]
Reporting unit fair value in excess of carrying amount (as a percent)	5.00%
Boots Reporting Unit \| Maximum
Goodwill [Line Items]
Reporting unit fair value in excess of carrying amount (as a percent)	27.00%