Income Taxes (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	May 31, 2012	May 31, 2014	May 31, 2013	May 31, 2012
Income Tax Disclosure [Abstract]
Income taxes paid		$ 172.5	$ 122.2	$ 160.8
Cash repatriated from foreign subsidiaries	110
Cash repatriated from foreign subsidiaries, income tax expense			8.9
Undistributed earnings of foreign subsidiaries	140.7	172.7	194.0	140.7
Unrecognized tax benefits that would impact effective tax rates if recognized		9.7	10.9
Unrecognized tax benefits, interest and penalties accrual		0.7	1.1
Unrecognized tax benefits period increase (decrease)		(0.2)	(29.2)	(55.0)
Unrecognized tax benefits, decrease in accrued interest		0.4	0.9	7.1
Potential increase (decrease) in the balance of unrecognized tax benefits		$ (0.7)