Leases - Supplemental Cash Flow Information (Details) $ in Millions	3 Months Ended
	Nov. 30, 2019 USD ($)
Leases [Abstract]
Gains on sale-leaseback transactions1	$ 77
Cash paid for amounts included in the measurement of lease obligations
Operating cash flows from operating leases	831
Operating cash flows from finance leases	11
Financing cash flows from finance leases	13
Total	855
Right-of-use assets obtained in exchange for new lease obligations:
Operating leases	$ 552