Significant Accounting Policies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) Customer	Dec. 31, 2014 USD ($) Customer	Dec. 31, 2013 USD ($) Customer	Mar. 31, 2016 USD ($)
Significant Accounting Policies [Line Items]
Maturity of highly liquid investments	3 months
Maturity period of cash flow hedge derivatives	1 year
Maturity period of non designated hedges derivatives	1 year
Contractual period	1 year
Warranty period for hardware products (in years)	1 year
Warranty period for software (in days)	90 days
Advertising expense	$ 20.2	$ 19.2	$ 20.1
More than likely percentage of being realized upon settlement, tax benefit	50.00%
Liability for unrecognized tax benefits as current	1 year
Reduction in debt liabilities due to ASU No. 2015-03	$ (1,948.7)
Accounting Standards Update 2015-03 [Member] | Scenario, Forecast [Member]
Significant Accounting Policies [Line Items]
Reduction in unamortized debt issuance expense due to ASU No. 2015-03				$ 11.0
Reduction in debt liabilities due to ASU No. 2015-03				$ 11.0
Sales Revenue, Segment [Member] | Customer Concentration Risk [Member]
Significant Accounting Policies [Line Items]
Number of customers accounting for more than 10% of revenues | Customer	0	0	0
Minimum [Member]
Significant Accounting Policies [Line Items]
Contractual support period	1 year
Maximum [Member]
Significant Accounting Policies [Line Items]
Contractual support period	3 years
Computer, Equipment and Software [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Useful life	3 years
Computer, Equipment and Software [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Useful life	7 years
Furniture and fixtures [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Useful life	5 years
Furniture and fixtures [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Useful life	7 years
Building and Building Improvements [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Useful life	7 years
Building and Building Improvements [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Useful life	40 years
Land Improvements [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Useful life	5 years
Land Improvements [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Useful life	40 years
Leasehold Improvements [Member]
Significant Accounting Policies [Line Items]
Useful life	10 years