Leases - Schedule of Supplemental Cash Flow Information Related to Leases (Details) $ in Millions	3 Months Ended
	Aug. 31, 2019 USD ($)
Leases [Abstract]
Operating cash flows paid for operating leases	$ 635
Operating cash flows paid for interest portion of finance leases	1
Financing cash flows paid for principal portion of finance leases	27
Right-of-use assets obtained in exchange for new operating lease liabilities	235
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 76