Common Stock and Stock-Based Compensation - Stock Option Transactions Under Plan (Detail) - Stock Incentive Plan - $ / shares shares in Millions	12 Months Ended
	May 31, 2016	May 31, 2015	May 31, 2014
Options Outstanding - Shares
Beginning Balance (in shares)	116.2	127.1	135.3
Exercised (in shares)	(22.5)	(27.2)	(22.0)
Forfeited (in shares)	(2.3)	(2.1)	(2.5)
Granted (in shares)	20.6	18.4	16.3
Ending Balance (in shares)	112.0	116.2	127.1
Options exercisable (in shares)	66.5	68.6	74.0
Options Outstanding - Weighted-Average Option Price
Beginning Balance (in dollars per share)	$ 23.50	$ 19.64	$ 17.36
Exercised (in dollars per share)	17.75	15.39	14.15
Forfeited (in dollars per share)	39.96	29.51	24.17
Granted (in dollars per share)	56.41	38.84	31.77
Ending Balance (in dollars per share)	30.38	23.50	19.64
Options exercisable (in dollars per share)	$ 21.48	$ 18.26	$ 15.71