Business and Summary of Significant Accounting Policies - Stock Based Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense related to stock awards and Employee Qualified Stock Purchase Plan (ESPP) purchases	$ 221.8	$ 197.2	$ 165.6
Tax benefit	(2.6)	(1.6)	(45.2)
Stock-based compensation expense related to stock awards and ESPP purchases, net	219.2	195.6	120.4
Cost of subscription
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense related to stock awards and Employee Qualified Stock Purchase Plan (ESPP) purchases	7.0	5.7	4.3
Cost of license and other revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense related to stock awards and Employee Qualified Stock Purchase Plan (ESPP) purchases	7.1	6.1	4.6
Marketing and sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense related to stock awards and Employee Qualified Stock Purchase Plan (ESPP) purchases	94.1	85.2	72.4
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense related to stock awards and Employee Qualified Stock Purchase Plan (ESPP) purchases	81.3	70.4	56.0
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense related to stock awards and Employee Qualified Stock Purchase Plan (ESPP) purchases	$ 32.3	$ 29.8	$ 28.3