Stock-Based Compensation (Stock Options Granted and Outstanding) (Details) (USD $)					12 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2011	May 31, 2010	May 31, 2013 Stock Options [Member]	May 31, 2012 Stock Options [Member]	May 31, 2011 Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, beginning of period (shares)					7,609,117	7,664,703	6,467,206
Granted (shares)					1,722,081	1,638,907	2,030,764
Canceled (shares)					(884,384)	(1,591,480)	(833,267)
Exercised (shares)					(561,176)	(103,013)	0
Outstanding, end of period (shares)					7,885,638	7,609,117	7,664,703
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, begining of period, Weighted Average Exercise Price (dollars per share)					$ 36.04	$ 36.12	$ 37.63
Granted, Weighted Average Exercise Price (dollars per share)					$ 44.67	$ 36.26	$ 32.42
Canceled, Weighted Average Exercise Price (dollars per share)					$ 38.69	$ 36.90	$ 38.76
Exercised, Weighted Average Exercise Price (dollars per share)					$ 36.44	$ 32.66	$ 0.00
Outstanding, end of period, Weighted Average Exercise Price (dollars per share)					$ 37.60	$ 36.04	$ 36.12
Number of exercisable options (shares)	1,815,795	2,105,702	1,945,207	1,838,530