Earnings Per Share (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended				1 Months Ended	15 Months Ended
	Aug. 31, 2014	Aug. 31, 2013	Aug. 31, 2014 Common Stock	Aug. 31, 2014 Common Stock Employee payroll taxes due on restricted stock	Oct. 10, 2014 Common Stock Subsequent Event	Oct. 10, 2014 Common Stock Subsequent Event	Jul. 30, 2013 July 30, 2013
Earnings Per Share, Basic and Diluted [Line Items]
Earnings per share from discontinued operations (less than $0.01 per share for both periods)	$ 0.01	$ 0.01
Options granted and excluded from the computation of diluted earnings per share (shares)	600,000	600,000
Additional amount authorized under share buyback program							500,000,000
Common stock purchased under a share buyback program (shares)			800,000	200,000	0	4,100,000
Aggregate purchase price of common stock under a share buyback program			$ 49.7	$ 11.7		$ 249.2
Average price of common stock purchased under a share buyback program (dollars per share)			$ 62.17	$ 63.72		$ 60.19