Leases - supplemental balance sheet information (Details) - USD ($) $ in Millions	Aug. 31, 2022	Aug. 31, 2021
Operating leases:
Operating lease right-of-use assets	$ 21,259	$ 21,893
Operating lease obligations - current	2,286	2,259
Operating lease obligations - non-current	21,517	22,153
Total operating lease obligations	23,803	24,412
Finance leases:
Property, plant and equipment, net	645	725
Lease obligations included in:
Accrued expenses and other liabilities	37	37
Other non-current liabilities	899	974
Total finance lease obligations	$ 936	$ 1,010
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