General - Schedule of Recently Adopted Accounting Standards (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Nov. 30, 2018	Nov. 30, 2017	Nov. 30, 2018	Nov. 30, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Revenues	$ 17,824	$ 16,313	$ 34,876	$ 31,610
Operating Income	1,168	1,115	2,239	2,086
Other Income (Expense), net	9	24	39	35
NET INCOME	$ 935	775	$ 1,770	1,371
Effect of Adoption of ASU 2017-07 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Operating Income		(147)		(293)
Other Income (Expense), net		147		293
Reported [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Revenues		16,313		31,610
Operating Income		1,262		2,379
Other Income (Expense), net		(123)		(258)
NET INCOME		$ 775		$ 1,371