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Fair value portion of investments accounted under the equity method.

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Equity method investments - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Nov. 30, 2021	Nov. 30, 2020	Sep. 30, 2020	Aug. 31, 2021
Schedule of Equity Method Investments [Line Items]
Equity earnings (losses)	$ 93	$ (1,350)
AmerisourceBergen
Schedule of Equity Method Investments [Line Items]
Outstanding shares owned (in shares)	58,854,867			58,854,867
Ownership percentage	28.30%			28.30%
Period of reporting lag	2 months
Equity earnings (losses)	$ 100	(1,400)
Equity investment, exceeded its proportionate share of net assets	4,300
AmerisourceBergen \| Opiod Litigation
Schedule of Equity Method Investments [Line Items]
Equity earnings (losses)			$ (5,600)
AmerisourceBergen \| Level 1
Schedule of Equity Method Investments [Line Items]
Fair market value of equity investment	6,800			$ 7,200
Other Investments
Schedule of Equity Method Investments [Line Items]
Equity earnings (losses)	(7)	$ 15
VillageMD
Schedule of Equity Method Investments [Line Items]
Gain on sale of equity method investment	$ 2,174