Income Taxes (Details 6) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Deferred income taxes	$ 8.9	$ 7.9
Other noncurrent liabilities	11.2	11.7
Net unrecognized tax benefits	20.1	19.6
Gross unrecognized tax benefits	$ 20.1	$ 22.9	$ 44.5	$ 143.9