Earnings Per Share - Reconciliation from Basic Earnings Per Share to Diluted Earnings Per Share (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2011
Determination of shares:
Weighted average common shares outstanding (in shares)	897.3	920.0	951.1
Assumed conversion of dilutive stock options and awards (in shares)	19.1	19.6	20.2
DILUTED WEIGHTED AVERAGE COMMON SHARES OUTSTANDING (in shares)	916.4	939.6	971.3
Earnings per share from continuing operations:
Income (Loss) from Continuing Operations, Per Basic Share (in dollars per share)	$ 2.75	$ 2.47	$ 2.28
Income (Loss) from Continuing Operations, Per Diluted Share (in dollars per share)	$ 2.69	$ 2.42	$ 2.24
Earnings per share from discontinued operations:
Income (Loss) from Discontinued Operations, Per Basic Share (in dollars per share)	$ 0.02	$ (0.05)	$ (0.04)
Income (Loss) from Discontinued Operations, Per Diluted Share (in dollars per share)	$ 0.02	$ (0.05)	$ (0.04)
Basic earnings per common share (in dollars per share)	$ 2.77	$ 2.42	$ 2.24
Diluted earnings per common share (in dollars per share)	$ 2.71	$ 2.37	$ 2.20