Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Taxes [Abstract]
Foreign subsidiaries tax payable period			8 years
U.S. federal corporate tax rate			21.00%		35.00%
Change in tax rate, income tax benefit	$ (97.8)				$ (89.6)
Increase in tax rate, income tax benefit			$ 8.2
Benefit relating to the reduction of the ASC 740-30 liability			69.0
Recorded provisional transition tax obligation			51.7		$ 63.3
Income (loss) before income taxes	94.8	$ 32.4	238.1	$ (166.3)
Provision (benefit) for income taxes	$ 22.6	$ 4.4	$ 63.2	$ (41.2)
Effective income tax rate	23.80%	13.60%	26.50%	24.80%