Debt (Loss on Extinguishment of Debt and Other Related Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
Loss on extinguishment of debt	$ 0.3	$ 0.8	$ 196.2
Payment of premiums due on debt instruments			148.1
Early tender consideration for purchase of senior notes			28.7
Premiums paid on extinguishment of debt			1.6
Write off of deferred debt issuance costs and unamortized discounts			17.8
Non-cash interest expense			$ 7.2