Goodwill and Other Intangible Assets - Schedule of Intangible Assets (Detail) (USD $) In Millions, unless otherwise specified	Aug. 31, 2014	May 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 5,286.8	$ 5,309.6
Accumulated Amortization	(1,936.0)	(1,870.0)
Net Carrying Amount	3,350.8	3,439.6
Core technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,736.4	1,743.3
Accumulated Amortization	(590.9)	(569.8)
Net Carrying Amount	1,145.5	1,173.5
Completed technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	670.1	672.0
Accumulated Amortization	(272.6)	(262.1)
Net Carrying Amount	397.5	409.9
Product trade names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	205.5	208.1
Accumulated Amortization	(79.8)	(77.6)
Net Carrying Amount	125.7	130.5
Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,362.4	2,371.6
Accumulated Amortization	(988.1)	(955.9)
Net Carrying Amount	1,374.3	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	4,979.3	4,999.9
Accumulated Amortization	(1,936.0)	(1,870.0)
Net Carrying Amount	3,043.3	3,129.9
Corporate trade names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	307.5	309.7
Accumulated Amortization	0	0
Net Carrying Amount	$ 307.5	$ 309.7