Income Taxes Additional Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Income Taxes [Line Items]
Increase Decrease In Income taxes Payable Current	$ 0.9
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Benefits	191.6
Income (Loss) from Continuing Operations before Income Taxes, Foreign	380.5	383.3	383.7
Valuation Allowance, Deferred Tax Asset, Change in Amount	15.9	3.8	4.6
Deferred Tax Liability Not Recognized, Cumulative Amount of Temporary Difference	1,690.0
Deferred Tax Liability Not Recognized, Amount of Unrecognized Deferred Tax Liability	491.4
Net deferred tax assets	187.9	165.0
Foreign Income Tax Expense (Benefit), Continuing Operations	9.7	6.6	10.4
Income Tax Holiday, Income Tax Benefits Per Share	$ 0.04	$ 0.03	$ 0.05
Current Foreign Tax Expense (Benefit)	63.9	54.3	55.9
Gross unrecognized tax benefits	222.1	212.7	201.1	188.4
Amount of gross unrecognized tax benefits that would impact the effective tax rate, if recognized	214.5
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	2.8	1.9	2.4
Domestic Country
Income Taxes [Line Items]
Operating Loss Carryforwards	17.0
State and Local Jurisdiction
Income Taxes [Line Items]
Operating Loss Carryforwards	322.9
State and Local Jurisdiction and the Internal Revenue Service
Income Taxes [Line Items]
Operating Loss Carryforwards	9.8
Research
Income Taxes [Line Items]
Tax Credit Carryforward, Amount	96.1
California State Research
Income Taxes [Line Items]
Tax Credit Carryforward, Amount	49.8
Canadian
Income Taxes [Line Items]
Tax Credit Carryforward, Amount	63.4
Foreign Country
Income Taxes [Line Items]
Tax Credit Carryforward, Amount	$ 107.6