Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	3 Months Ended
	Nov. 30, 2020	Nov. 30, 2019
Cash paid for amounts included in the measurement of lease obligations
Operating cash flows from operating leases	$ 872	$ 831
Operating cash flows from finance leases	12	11
Financing cash flows from finance leases	11	13
Total	895	855
Right-of-use assets obtained in exchange for new lease obligations:
Operating leases	$ 805	$ 552