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Financial instruments - Summary of Variable Prepaid Forward Transactions (Details) - USD ($) shares in Millions, $ in Millions						3 Months Ended			6 Months Ended	9 Months Ended		12 Months Ended
	Nov. 09, 2023	Aug. 04, 2023	Aug. 03, 2023	Jun. 15, 2023	May 11, 2023	May 31, 2025	Feb. 28, 2025	May 31, 2024	Nov. 09, 2023	May 31, 2025	May 31, 2024	Aug. 31, 2024
Derivatives, Fair Value [Line Items]
Prepayment amount										$ 103	$ 424
Gain (loss) on variable prepaid forward contracts										766	(733)
Derivative Financial Instruments, Liabilities \| Realized Gain (Loss)
Derivatives, Fair Value [Line Items]
Realized gains (losses) recorded in Other income (expense), net						$ 378	$ 955	$ 0		$ 1,333	$ 0
Derivatives not designated as hedges:
Derivatives, Fair Value [Line Items]
Prepayment amount									$ 2,991
Shares pledged and maximum shares subject to forward sale (in shares)									10.4
Derivatives not designated as hedges: \| Cencora
Derivatives, Fair Value [Line Items]
Shares pledged and maximum shares subject to forward sale (in shares)						10.4						20.0
Early settlement (in shares)						2.2	6.1			6.1
Outstanding shares owned (in shares)							1.3
Early settlement value received (paid)						$ 103	$ (20)			$ (20)
Derivatives not designated as hedges: \| Fourth quarter, fiscal 2025
Derivatives, Fair Value [Line Items]
Prepayment amount					$ 644
Shares pledged and maximum shares subject to forward sale (in shares)					4.6
Derivatives not designated as hedges: \| Third quarter, fiscal 2025
Derivatives, Fair Value [Line Items]
Prepayment amount				$ 325
Shares pledged and maximum shares subject to forward sale (in shares)				0.0
Derivatives not designated as hedges: \| First quarter, fiscal 2026
Derivatives, Fair Value [Line Items]
Prepayment amount			$ 801
Shares pledged and maximum shares subject to forward sale (in shares)			5.3
Derivatives not designated as hedges: \| Third quarter, fiscal 2026
Derivatives, Fair Value [Line Items]
Prepayment amount		$ 797
Shares pledged and maximum shares subject to forward sale (in shares)		0.0
Derivatives not designated as hedges: \| Fourth quarter, fiscal 2026
Derivatives, Fair Value [Line Items]
Prepayment amount	$ 424
Shares pledged and maximum shares subject to forward sale (in shares)	0.5