Investments - Investments in Equity Securities (Details) $ in Millions	6 Months Ended
	Jun. 30, 2023 USD ($)
Equity Securities
Beginning balance	$ 96.5
Decrease in fair value of investments in equity securities	(6.6)
Foreign currency translation adjustments and other	0.0
Ending balance	89.9
Investment in Equity Securities Level 1
Equity Securities
Beginning balance	17.2
Decrease in fair value of investments in equity securities	(6.2)
Foreign currency translation adjustments and other	0.3
Ending balance	11.3
Investment in Equity Securities, Level 2
Equity Securities
Beginning balance	7.8
Decrease in fair value of investments in equity securities	(0.4)
Foreign currency translation adjustments and other	0.0
Ending balance	7.4
Investments in Equity Securities, All Others
Equity Securities
Beginning balance	71.5
Decrease in fair value of investments in equity securities	0.0
Foreign currency translation adjustments and other	(0.3)
Ending balance	$ 71.2