Accounting Policies New Accounting Pronouncements (Details) - USD ($) $ in Millions		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Reclassification for stranded tax effects resulting from the the Tax Reform Act	$ 1.6
General and administrative expenses		$ 247.6	$ 175.9	$ 106.1
Other (income) expense, net		(7.3)	(6.1)	0.4
Decrease in retained earnings		(981.8)	(767.8)
Distributions from equity method investments		$ 1.2	12.4	$ 20.2
As Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
General and administrative expenses			169.8
Other (income) expense, net			0.0
Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
General and administrative expenses			6.1
Other (income) expense, net			$ (6.1)
Accounting Standards Update 2016-16 | Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Decrease in retained earnings	$ 44.4