Taxes (Details) - Schedule of provision for income taxes (USD $) In Millions, unless otherwise specified	12 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2011
Federal
Current	$ 4.5	$ 49.1	$ 10.2
Deferred	2.4	(8.2)	9.1
	6.9	40.9	19.3
State and local
Current	0.5	12.0	3.8
Deferred	2.2	(0.7)	2.2
	2.7	11.3	6.0
International
Current	7.8	12.8	12.5
Deferred	0.2	(3.4)	1.0
	8.0	9.4	13.5
Total
Current	12.8	73.9	26.5
Deferred	4.8	(12.3)	12.3
	$ 17.6	$ 61.6	$ 38.8