Income Taxes (Significant Components Of Deferred Tax Assets And Liabilities) (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Mar. 31, 2012
Deferred tax assets:
Deferred revenue	$ 77.9	$ 73.4
Compensation plans	46.6	47.0
Property and equipment, net	8.2	4.1
Net operating loss carryforwards	41.4	52.8
Tax credit carryforwards	11.4	10.0
Other	74.8	67.2
Total gross deferred tax assets	260.3	254.5
Valuation allowance	(18.5)	(20.5)
Total deferred tax assets	241.8	234.0
Deferred tax liabilities:
Software development costs	(105.4)	(88.2)
Acquired intangible assets	(81.9)	(85.6)
Other	(61.3)	(56.3)
Total deferred tax liabilities	(248.6)	(230.1)
Net deferred tax assets (liabilities)	(6.8)	3.9
As reported:
Current deferred tax assets	81.3	71.0
Other Long-Term Assets [Member]
As reported:
Other long-term assets	26.0	22.7
Accrued Liabilities [Member]
As reported:
Accrued liabilities	(2.8)	(0.4)
Other Long-Term Liabilities [Member]
As reported:
Other long-term liabilities	$ (111.3)	$ (89.4)