Leases - Schedule of Supplemental Balance Sheet Information Related to Leases (Details) - USD ($) $ in Millions	May 31, 2021	May 31, 2020
Operating leases:
Operating lease right-of-use assets, net	$ 15,383	$ 13,917
Current portion of operating lease liabilities	2,208	1,923
Operating lease liabilities	13,375	12,195
Total operating lease liabilities	15,583	14,118
Finance leases:
Net property and equipment	$ 504	$ 480
Finance Lease, Right of Use Asset, Statement of Financial Position [Extensible List]	Net Book Value at May 31,	Net Book Value at May 31,
Current portion of long-term debt	$ 96	$ 51
Finance Lease, Liability, Current Statement of Financial Position [Extensible List]	LONG-TERM DEBT, LESS CURRENT PORTION	LONG-TERM DEBT, LESS CURRENT PORTION
Long-term debt, less current portion	$ 429	$ 434
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	LONG-TERM DEBT, LESS CURRENT PORTION	LONG-TERM DEBT, LESS CURRENT PORTION
Total finance lease liabilities	$ 525	$ 485
Weighted-average remaining lease term
Operating leases	9 years 10 months 24 days	9 years 10 months 24 days
Finance leases	30 years 1 month 6 days	32 years
Weighted-average discount rate
Operating leases	2.94%	3.19%
Finance leases	3.43%	3.58%