Leases - Other Supplemental Information (Details) - USD ($) $ in Millions	6 Months Ended
	Feb. 28, 2021	Feb. 29, 2020
Cash paid for amounts included in the measurement of lease obligations
Operating cash flows from operating leases	$ 1,702	$ 1,657
Operating cash flows from finance leases	24	24
Financing cash flows from finance leases	20	21
Total	1,746	1,702
Right-of-use assets obtained in exchange for new lease obligations:
Operating leases	1,492	1,284
Finance leases	0	59
Total	$ 1,492	$ 1,343