Earnings per Share Narrative (Details) (USD $)	0 Months Ended	1 Months Ended	2 Months Ended		9 Months Ended	12 Months Ended
	Oct. 18, 2011	Jul. 30, 2012	May 31, 2012	Jul. 29, 2011	Jul. 30, 2012	May 31, 2012	May 31, 2011	May 31, 2010
Earnings Per Share, Basic and Diluted [Line Items]
Options granted excluded from the computation of diluted earnings per share (in shares)						2,000,000	3,900,000	4,500,000
Common stock purchased under a share buyback program (in shares)			3,300,000	8,100,000		11,400,000
Average price of common stock purchased under a share buyback program (in dollars per share)						$ 34.24
Aggregate purchase price of common stock under a share buyback program (in dollars)			$ 129,600,000	$ 259,500,000		$ 389,100,000
Additional amount authorized under share buyback program	500,000,000
Repurchase of common stock (in shares)		600,000			3,900,000
Treasury Stock Acquired, Average Cost Per Share					$ 38.86
Repurchase of common stock		23,700,000			153,300,000	392,328,000	443,690,000	969,000
Employee Payroll Taxes Due on Restricted Stock [Member]
Earnings Per Share, Basic and Diluted [Line Items]
Common stock purchased under a share buyback program (in shares)						100,000
Average price of common stock purchased under a share buyback program (in dollars per share)					$ 32.05
Aggregate purchase price of common stock under a share buyback program (in dollars)					$ 3,200,000