Exit and disposal activities - Restructuring Costs (Details) - Transformational Cost Management Program - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	May 31, 2022	May 31, 2021	May 31, 2022	May 31, 2021
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	$ 173	$ 44	$ 404	$ 279
Reportable segments | United States
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	117	2	283	172
Reportable segments | International
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	45	27	97	63
Corporate and Other
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	11	14	25	44
Lease obligations and other real estate costs
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	18	21	113	62
Lease obligations and other real estate costs | Reportable segments | United States
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	16	15	107	56
Lease obligations and other real estate costs | Reportable segments | International
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	3	6	6	6
Lease obligations and other real estate costs | Corporate and Other
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	0	0	0	0
Asset impairments
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	61	14	105	19
Asset impairments | Reportable segments | United States
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	48	5	64	9
Asset impairments | Reportable segments | International
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	14	9	42	10
Asset impairments | Corporate and Other
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	0	0	0	0
Employee severance and business transition costs
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	86	(2)	166	172
Employee severance and business transition costs | Reportable segments | United States
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	53	(19)	110	92
Employee severance and business transition costs | Reportable segments | International
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	22	2	32	36
Employee severance and business transition costs | Corporate and Other
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	11	14	25	44
Information technology transformation and other exit costs
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	7	11	20	26
Information technology transformation and other exit costs | Reportable segments | United States
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	1	1	3	14
Information technology transformation and other exit costs | Reportable segments | International
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	6	10	18	11
Information technology transformation and other exit costs | Corporate and Other
Restructuring Cost and Reserve [Line Items]
Total pre-tax exit and disposal charges	$ 0	$ 0	$ 0	$ 1