Accumulated Other Comprehensive Income - Reclassification out of AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2016	May 31, 2015	May 31, 2014
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other expense (income), net	$ 140	$ 58	$ (103)
Revenues	32,376	30,601	27,799
Cost of sales	(17,405)	(16,534)	(15,353)
Selling and administrative expense	(10,469)	(9,892)	(8,766)
Income before income taxes	4,623	4,205	3,544
Tax benefit (expense)	(863)	(932)	$ (851)
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	709	299
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	(2)	0
Income before income taxes	(2)	0
Tax benefit (expense)	0	0
Gain (loss), net of tax	(2)	0
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	717	261
Tax benefit (expense)	(7)	(2)
Gain (loss), net of tax	710	259
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	219	136
Revenues	(88)	(95)
Cost of sales	586	220
Selling and administrative expense	0	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	3	40
Income before income taxes	3	40
Tax benefit (expense)	(2)	0
Gain (loss), net of tax	$ 1	$ 40