General - Schedule of Recently Adopted Accounting Standards (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 28, 2019	Feb. 28, 2018	Feb. 28, 2019	Feb. 28, 2018
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Revenues	$ 17,010	$ 16,526	$ 51,886	$ 48,136
Operating Income	911	858	3,150	2,944
Other Income (Expense), net	20	16	59	51
NET INCOME	$ 739	2,074	$ 2,509	3,445
Effect of Adoption of ASU 2017-07 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Operating Income		(143)		(436)
Other Income (Expense), net		143		436
Reported [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Revenues		16,526		48,136
Operating Income		1,001		3,380
Other Income (Expense), net		(127)		(385)
NET INCOME		$ 2,074		$ 3,445