Supplemental information - schedule of redeemable non-controlling interest (Details) - USD ($) $ in Millions	12 Months Ended
Aug. 31, 2024	Aug. 31, 2023	Aug. 31, 2022
Increase (Decrease) in Temporary Equity [Roll Forward]
Beginning balance	$ 167	$ 1,042	$ 319
Recognition upon acquisition of subsidiary	0	0	2,684
Acquisitions of non-controlling interests	0	0	(2,047)
Net income (loss) attributable to Redeemable non-controlling interests	1	(21)	(73)
Redemption price adjustments	6	460	159
Reclassifications to accrued expenses and other liabilities	0	(1,314)	0
Ending balance	174	167	1,042
Conversion of Stock [Line Items]
Recognition upon acquisition of subsidiary	$ 0	$ 0	2,684
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.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
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-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
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-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 323
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Redemption of temporary equity as the result of a triggering event associated with the temporary equity.

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Temporary Equity, Acquisitions of Non-Controlling Interests

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