Acquisitions and other investments - Schedule of Pro Forma and Actual Information (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Feb. 28, 2023	Feb. 28, 2022	Feb. 28, 2023	Feb. 28, 2022
Summit Health-CityMD
Business Acquisition [Line Items]
Sales, pro forma	$ 35,119	$ 34,402	$ 69,216	$ 68,924
Sales, actual	$ 463		$ 463
VillageMD, Shields And CareCentrix
Business Acquisition [Line Items]
Sales, pro forma		34,063		68,627
Sales, actual		$ 527		$ 577

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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- Definition

The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(2)
-URI https://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
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-URI https://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
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