Exit and disposal activities - Restructuring Reserve Activity (Details) - Transformational Cost Management Program $ in Millions	6 Months Ended
	Feb. 28, 2022 USD ($)
Restructuring Reserve [Roll Forward]
Beginning balance	$ 114
Costs	231
Payments	(160)
Other	(102)
Ending balance	83
Lease obligations and other real estate costs
Restructuring Reserve [Roll Forward]
Beginning balance	17
Costs	95
Payments	(39)
Other	(55)
Ending balance	18
Asset Impairments
Restructuring Reserve [Roll Forward]
Beginning balance	0
Costs	44
Payments	0
Other	(44)
Ending balance	0
Employee severance and business transition costs
Restructuring Reserve [Roll Forward]
Beginning balance	77
Costs	79
Payments	(104)
Other	(3)
Ending balance	50
Information technology transformation and other exit costs
Restructuring Reserve [Roll Forward]
Beginning balance	20
Costs	13
Payments	(18)
Other	0
Ending balance	$ 16