Income Tax Unrecognized Tax Benefits Balance (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Estimated interest and penalties	$ 5.7	$ 5.3	$ 7.2
Offsetting positions	0.0	(3.7)	(3.7)
Unrecognized tax positions	39.7	39.5	59.8	$ 137.9
Total unrecognized tax benefits	45.4	41.1	63.3
Presented net against non-current deferred tax assets	32.7	30.9	37.9
Current (included in accounts payable and other current liabilities)	3.0	1.8	0.0
Unrecognized tax benefits	9.7	8.4	25.4
Amount of unrecognized tax benefits that would impact the effective tax rate, if recognized(1)	$ 39.7	$ 39.5	$ 59.8