Supplemental Financial Data - Deferred Tax Asset Valuation Allowance (Details) - SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Feb. 07, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 34.4	$ 33.1	$ 34.4	$ 39.1
Additions charged (credited) to costs and expenses	0.0	0.5	(27.2)	(2.8)
Additions charged (credited) due to foreign currency fluctuations	0.0	2.2	(0.5)	(1.9)
Additions charged (credited) to other accounts	0.0	0.0		0.0
Acquisition			60.8
Balance at end of period	$ 34.4	$ 35.8	$ 33.1	$ 34.4