Supplemental Financial Statement Information - Cash and Cash Equivalents (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash and Cash Equivalents [Abstract]
Cash	$ 164.1	$ 149.3
Other short-term investments	65.5	0.5
Total cash and cash equivalents	$ 229.6	$ 149.8	$ 269.5	$ 1,026.8