Exit and disposal activities - restructuring reserve activity (Details) - Transformational cost management program - USD ($) $ in Millions	12 Months Ended
	Aug. 31, 2021	Aug. 31, 2020
Restructuring Reserve [Roll Forward]
Beginning balance	$ 199	$ 47
Costs	335	665
Payments	(351)	(276)
Other - non cash	(70)	(236)
ASC 842 leases adoption		(4)
Currency	1	3
Ending balance	114	199
Lease obligations and other real estate costs
Restructuring Reserve [Roll Forward]
Beginning balance	19	17
Costs	108	215
Payments	(69)	(44)
Other - non cash	(42)	(166)
ASC 842 leases adoption		(4)
Currency	0	1
Ending balance	17	19
Asset impairments
Restructuring Reserve [Roll Forward]
Beginning balance	0	0
Costs	24	72
Payments	0	0
Other - non cash	(24)	(72)
ASC 842 leases adoption		0
Currency	0	0
Ending balance	0	0
Employee severance and business transition costs
Restructuring Reserve [Roll Forward]
Beginning balance	166	27
Costs	165	270
Payments	(252)	(146)
Other - non cash	(4)	13
ASC 842 leases adoption		0
Currency	2	2
Ending balance	77	166
Information technology transformation and other exit costs
Restructuring Reserve [Roll Forward]
Beginning balance	14	3
Costs	38	108
Payments	(31)	(86)
Other - non cash	0	(11)
ASC 842 leases adoption		0
Currency	(1)	0
Ending balance	$ 20	$ 14