Goodwill and Purchased Intangible Assets, Goodwill (Details) $ in Millions	6 Months Ended
	Jun. 30, 2016 USD ($)
Goodwill [Roll Forward]
Balance as of December 31, 2015	$ 2,981.3
Additions due to business combination	20.3
Balance as of June 30, 2016	$ 3,001.6