Accumulated Other Comprehensive Income - Reclassification out of AOCI (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Aug. 31, 2013	Aug. 31, 2012
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales	$ 3,839	$ 3,646
Selling and administrative expense	2,056	2,059
Tax (expense) benefit	(260)	(215)
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	29
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]
Total before tax	35
Tax (expense) benefit	(5)
Gain (loss) net of tax	30
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]
Revenue	14
Cost of sales	16
Selling and administrative expense	0
Other expense (income), net	5
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	(1)
Total before tax	(1)
Tax (expense) benefit	0
Gain (loss) net of tax	$ (1)