Income Taxes Components Of Deferred Tax Assets and Liabilities (Details) (USD $)
In Millions, unless otherwise specified
Jan. 31, 2014
Jan. 31, 2013
Income Tax Disclosure [Abstract]    
Nonqualified stock options $ 37.4 $ 67.5
Research and development tax credit carryforwards 78.4 54.0
Foreign tax credit carryforwards 16.3 0
Accrued compensation and benefits 38.6 34.5
Other accruals not currently deductible for tax 14.5 15.3
Purchased technology and capitalized software 23.4 9.8
Fixed assets 17.5 18.5
Tax loss carryforwards 12.6 21.0
Deferred Revenue 33.1 28.5
Other 5.1 2.2
Total deferred tax assets 276.9 251.3
Less: valuation allowance (67.2) (51.3)
Net deferred tax assets 209.7 200.0
Tax method change on advanced payments 0 (3.1)
Unremitted earnings of foreign subsidiaries (21.8) (31.9)
Total deferred tax liability (21.8) (35.0)
Net deferred tax assets $ 187.9 $ 165.0