Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	May 31, 2020	May 31, 2021	May 31, 2020	May 31, 2019	May 31, 2018
Income Taxes [Line Items]
Earnings From Foreign Operations		$ 1,800	$ 634	$ 929
Income tax benefit		(1,443)	(383)	$ (115)
Statutory Federal Income Tax Rate				21.00%	29.20%
Benefit from reduction of valuation allowance on tax loss carryforwards			133	$ 90
Deferred income tax expense	$ 51	802	348	(85)
Income tax benefit from accelerated deductions to be claimed on 2018 tax return				75
Reduction in valuation allowance balance		(14)	129	79
Recognition of cumulative benefit from TCJA				$ 233
Unrecognized Tax Benefits That Would Impact Effective Tax Rate	127	190	127
Unrecognized Tax Benefits Accrued Income Tax Penalties And Interest	$ 41	61	41
Interest expense associated with uncertain tax positions		20
Foreign Country [Member]
Income Taxes [Line Items]
Operating Loss Carryforwards		3,000
Foreign Country [Member] | Fed Ex Express and TNT Express [Member]
Income Taxes [Line Items]
Reduction in valuation allowance balance		70
State And Local Jurisdiction [Member]
Income Taxes [Line Items]
Operating Loss Carryforwards		1,200
Domestic Tax Authority [Member]
Income Taxes [Line Items]
Operating Loss Carryforwards		$ 100
Maximum [Member]
Income Taxes [Line Items]
Statutory Federal Income Tax Rate				35.00%
Minimum [Member]
Income Taxes [Line Items]
Statutory Federal Income Tax Rate		21.00%
Netherlands [Member]
Income Taxes [Line Items]
Expense (benefit) from the impact on deferred tax assets attributable to a lower enacted tax rate		$ (66)		$ 50
IRS [Member]
Income Taxes [Line Items]
Income tax benefit		130
CARES Act [Member]
Income Taxes [Line Items]
Income tax benefit		$ 279	$ 71
Statutory Federal Income Tax Rate		35.00%	35.00%