Accumulated Other Comprehensive Income - Reclassification out of AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2016
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other expense (income), net	$ (66)	$ 196	$ 140
Interest expense (income), net	(54)	(59)	(19)
Revenues	36,397	34,350	32,376
Cost of sales	(20,441)	(19,038)	(17,405)
Selling and administrative expense	(11,511)	(10,563)	(10,469)
Income before income taxes	4,325	4,886	4,623
Tax benefit (expense)	(2,392)	(646)	$ (863)
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Gain (loss), net of tax	(160)	650
Gains (losses) on foreign currency translation adjustment | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other expense (income), net	0	(1)
Income before income taxes	0	(1)
Tax benefit (expense)	0	0
Gain (loss), net of tax	0	(1)
Gain (losses) on cash flow hedges | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	(131)	630
Tax benefit (expense)	3	3
Gain (loss), net of tax	(128)	633
Gain (losses) on cash flow hedges | Foreign exchange forwards and options | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other expense (income), net	(69)	199
Revenues	34	96
Cost of sales	(90)	339
Selling and administrative expense	1	0
Gain (losses) on cash flow hedges | Interest rate swaps | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Interest expense (income), net	(7)	(4)
Other | Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other expense (income), net	(32)	15
Income before income taxes	(32)	15
Tax benefit (expense)	0	3
Gain (loss), net of tax	$ (32)	$ 18