Supplemental information - Schedule of Redeemable Non-controlling Interest (Details) - USD ($) $ in Millions	12 Months Ended
Aug. 31, 2022	Aug. 31, 2021	Jan. 31, 2022
Increase (Decrease) in Temporary Equity [Roll Forward]
Beginning balance	$ 319	$ 0
Recognition upon acquisition of subsidiary	2,684	309
Redemption price adjustments	179	19
Net loss attributable to redeemable noncontrolling interest	(73)	(3)
Currency translation adjustments and other	(20)	(6)
Acquisitions of non-controlling interests	(2,047)
Ending balance	1,042	319
Conversion of Stock [Line Items]
Recognition upon acquisition of subsidiary	2,684	$ 309
VillageMD
Increase (Decrease) in Temporary Equity [Roll Forward]
Recognition upon acquisition of subsidiary	1,900
Conversion of Stock [Line Items]
Recognition upon acquisition of subsidiary	$ 1,900
McKesson Corporation, GEHE Pharma Handel
Conversion of Stock [Line Items]
Outstanding equity interest percentage			30.00%

Percentage of voting equity interests acquired at the acquisition date in the business combination.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Adjustments to temporary equity resulting from foreign currency translation adjustments.

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