Leases - supplemental balance sheet information (Details) - USD ($) $ in Millions	Aug. 31, 2023	Aug. 31, 2022
Operating leases:
Operating lease right-of-use assets	$ 21,667	$ 21,259
Operating lease obligations - current	2,347	2,286
Operating lease obligations - non-current	22,124	21,517
Total operating lease obligations	24,472	23,803
Finance leases:
Property, plant and equipment, net	678	645
Lease obligations included in:
Accrued expenses and other liabilities	57	37
Other non-current liabilities	919	899
Total finance lease obligations	$ 976	$ 936
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization	Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued expenses and other liabilities	Accrued expenses and other liabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other non-current liabilities	Other non-current liabilities