Fair Value Measurements, Equity Investments and Other Financial Instruments - Equity Investment Without Readily Determinable Fair Value (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Equity Securities without Readily Determinable Fair Value [Roll Forward]
Carrying value at the beginning of period		$ 25.4	$ 7.5	$ 7.5
Purchases		14.7	2.6	0.0
Impairments or downward adjustments		0.0	0.0	0.0
Upward adjustments	$ 6.6	6.6	15.1	0.0
Currency translation on investments		(0.9)	0.2	0.0
Carrying value at the end of period		$ 45.8	$ 25.4	$ 7.5