Leases - Schedule of liability for facility closings and related lease termination charges (Details) $ in Millions	12 Months Ended
	Aug. 31, 2019 USD ($)
Leases [Abstract]
Balance at beginning of period	$ 964
Provision for present value of non-cancelable lease payments on closed facilities	90
Changes in assumptions	56
Accretion expense	39
Other - non cash	160
Cash payments, net of sublease income	(316)
Balance at end of period	$ 993