Debt And Credit Facilities - Interest Expense (Details) - Convertible Debt - 2.375% convertible senior notes - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Contractual interest expense	$ 12.3	$ 7.5
Amortization of debt issuance costs	1.9	1.0
Amortization of debt discount	19.0	11.0
Total interest expense	$ 33.2	$ 19.5