Goodwill and Other Intangible Assets - Schedule of Intangible Assets (Detail) (USD $) In Millions, unless otherwise specified	Nov. 30, 2014	May 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 5,211.4	$ 5,309.6
Accumulated Amortization	(1,992.8)	(1,870.0)
Net Carrying Amount	3,218.6	3,439.6
Core technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,748.9	1,743.3
Accumulated Amortization	(605.4)	(569.8)
Net Carrying Amount	1,143.5	1,173.5
Completed technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	662.7	672.0
Accumulated Amortization	(281.3)	(262.1)
Net Carrying Amount	381.4	409.9
Product trade names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	188.8	208.1
Accumulated Amortization	(80.4)	(77.6)
Net Carrying Amount	108.4	130.5
Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,304.7	2,371.6
Accumulated Amortization	(1,021.1)	(955.9)
Net Carrying Amount	1,283.6	1,415.7
Non-compete contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	4.9	4.9
Accumulated Amortization	(4.6)	(4.6)
Net Carrying Amount	0.3	0.3
Sub-total [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	4,910.0	4,999.9
Accumulated Amortization	(1,992.8)	(1,870.0)
Net Carrying Amount	2,917.2	3,129.9
Corporate trade names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	301.4	309.7
Accumulated Amortization	0	0
Net Carrying Amount	$ 301.4	$ 309.7