Accumulated Other Comprehensive Income - Reclassification out of AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other expense (income), net	$ 196	$ 140	$ 58
Interest expense (income), net	(59)	(19)	(28)
Revenues	34,350	32,376	30,601
Cost of sales	(19,038)	(17,405)	(16,534)
Selling and administrative expense	(10,563)	(10,469)	(9,892)
Income before income taxes	4,886	4,623	4,205
Tax benefit (expense)	(646)	(863)	$ (932)
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	650	709
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	(1)	(2)
Income before income taxes	(1)	(2)
Tax benefit (expense)	0	0
Gain (loss), net of tax	(1)	(2)
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	630	717
Tax benefit (expense)	3	(7)
Gain (loss), net of tax	633	710
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	199	219
Revenues	96	(88)
Cost of sales	339	586
Selling and administrative expense	0	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	(4)	0
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	15	3
Income before income taxes	15	3
Tax benefit (expense)	3	(2)
Gain (loss), net of tax	$ 18	$ 1