Stock-Based Compensation (Range of Exercise Prices) (Details) (USD $)	12 Months Ended
	May 31, 2014
$ 20.29 – $ 34.17 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding (shares)	1,455,179
Outstanding Options, Average Remaining Option Life (years)	5 years 8 months 27 days
Outstanding Options, Weighted Average Exercise Price (dollars per share)	$ 27.12
Exercisable Options, Number Exercisable (shares)	658,257
Exercisable Options, Weighted Average Exercise Price (dollars per share)	$ 26.50
Exercise price range, lower limit (dollars per share)	$ 20.29
Exercise price range, upper limit (dollars per share)	$ 34.17
$ 34.18 – $ 37.80 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding (shares)	1,256,058
Outstanding Options, Average Remaining Option Life (years)	6 years 6 months 4 days
Outstanding Options, Weighted Average Exercise Price (dollars per share)	$ 34.88
Exercisable Options, Number Exercisable (shares)	146,089
Exercisable Options, Weighted Average Exercise Price (dollars per share)	$ 35.72
Exercise price range, lower limit (dollars per share)	$ 34.18
Exercise price range, upper limit (dollars per share)	$ 37.80
$ 37.81 – $ 43.00 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding (shares)	1,747,491
Outstanding Options, Average Remaining Option Life (years)	6 years 8 months 1 day
Outstanding Options, Weighted Average Exercise Price (dollars per share)	$ 38.57
Exercisable Options, Number Exercisable (shares)	359,434
Exercisable Options, Weighted Average Exercise Price (dollars per share)	$ 40.45
Exercise price range, lower limit (dollars per share)	$ 37.81
Exercise price range, upper limit (dollars per share)	$ 43.00
$ 43.01 – $ 62.12 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding (shares)	3,567,066
Outstanding Options, Average Remaining Option Life (years)	8 years 7 months 21 days
Outstanding Options, Weighted Average Exercise Price (dollars per share)	$ 55.32
Exercisable Options, Number Exercisable (shares)	419,633
Exercisable Options, Weighted Average Exercise Price (dollars per share)	$ 44.94
Exercise price range, lower limit (dollars per share)	$ 43.01
Exercise price range, upper limit (dollars per share)	$ 62.12
$ 20.29 – $ 62.12 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding (shares)	8,025,794
Outstanding Options, Average Remaining Option Life (years)	7 years 4 months 6 days
Outstanding Options, Weighted Average Exercise Price (dollars per share)	$ 43.12
Exercisable Options, Number Exercisable (shares)	1,583,413
Exercisable Options, Weighted Average Exercise Price (dollars per share)	$ 35.40
Exercise price range, lower limit (dollars per share)	$ 20.29
Exercise price range, upper limit (dollars per share)	$ 62.12