Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective income tax rate		12.90%	4.30%	42.30%
Recognition of provisional charge	$ 326.2
Adjustment to provisional amount recorded			$ 68.0
Unrecognized tax benefits that would impact effective tax rate	$ 146.2	$ 210.8	$ 189.5	$ 146.2