Fair Value Measurements (Details) - Schedule of non-financial assets measured and recorded at fair value on a non-recurring basis (USD $) In Millions, unless otherwise specified	12 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2011
Fair Value Measurements (Details) - Schedule of non-financial assets measured and recorded at fair value on a non-recurring basis [Line Items]
Investments, impairment losses			$ 3.6
Goodwill, net carrying value	157.9	157.7	154.2
Other intangible assets impairment	14.6	16.7
Other intangible assets impairment	14.6	16.7
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurements (Details) - Schedule of non-financial assets measured and recorded at fair value on a non-recurring basis [Line Items]
Other Intangible assets, measured fair value	0.3	5.4	5.6
Production assets		0.6
Investments, net carrying value			5.7
Investments, measured fair value			5.7
Goodwill, measured fair value		2.7	1.0
Other intangible assets impairment		4.9
Other intangible assets impairment		4.9
Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurements (Details) - Schedule of non-financial assets measured and recorded at fair value on a non-recurring basis [Line Items]
Other Intangible assets, net carrying value	0.3	5.4	5.6
Other Intangible assets, additions due to acquisitions	0.3	5.4	5.6
Production assets		0.6
Production assets		4.0
Property, plant and equipment, net, impairment losses	5.2		1.4
Prepublication assets, impairment losses	2.0	0.8	2.7
Investments, net carrying value			5.7
Investments, measured fair value			5.7
Investments, impairment losses		1.3	3.6
Goodwill impairment			3.4
Goodwill, net carrying value		2.7	1.0
Goodwill, additions due to acquisitions		2.7	1.0
Other intangible assets impairment		4.9
Other intangible assets impairment		4.9
Other intangible assets impairment		$ 6.8