Exit and disposal activities - restructuring reserve activity (Details) - USD ($) $ in Millions	12 Months Ended
	Aug. 31, 2024	Aug. 31, 2023
Restructuring Reserve [Roll Forward]
Restructuring Charges, Statement of Income or Comprehensive Income [Extensible Enumeration]	Selling, general and administrative expenses
Transformational cost management program
Restructuring Reserve [Roll Forward]
Beginning balance	$ 102	$ 113
Costs	835	1,158
Payments	(430)	(320)
Other - non cash	(471)	(849)
Ending balance	36	102
Transformational cost management program | Lease obligations and other real estate costs
Restructuring Reserve [Roll Forward]
Beginning balance	10	10
Costs	535	516
Payments	(223)	(105)
Other - non cash	(315)	(411)
Ending balance	8	10
Transformational cost management program | Asset impairments
Restructuring Reserve [Roll Forward]
Beginning balance	0	0
Costs	128	441
Payments	0	0
Other - non cash	(128)	(441)
Ending balance	0	0
Transformational cost management program | Employee severance and business transition costs
Restructuring Reserve [Roll Forward]
Beginning balance	70	76
Costs	102	150
Payments	(145)	(160)
Other - non cash	0	2
Ending balance	26	70
Transformational cost management program | Information technology transformation and other exit costs
Restructuring Reserve [Roll Forward]
Beginning balance	22	27
Costs	70	51
Payments	(62)	(55)
Other - non cash	(28)	0
Ending balance	$ 2	$ 22