Debt and Credit Arrangements - Interest Expense, Net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Debt Instrument
Interest expense, debt	$ 87.5		$ 216.0
Revolving Credit Facility
Debt Instrument
Interest expense, debt	50.5	$ 6.4	104.6	$ 14.7
Senior Secured And Unsecured Notes
Debt Instrument
Interest income	0.7		21.4
Senior secured notes due 2030 | Secured Debt
Debt Instrument
Interest expense, debt	27.3		82.1
Senior unsecured notes due 2031 | Unsecured Debt
Debt Instrument
Interest expense, debt	12.1		36.3
Term Loan Due 2030 | Revolving Credit Facility
Debt Instrument
Interest expense, debt	41.3	0.0	81.0	0.0
Convertible notes due November 2024 | Convertible Debt
Debt Instrument
Interest expense, debt	0.6		1.9
Senior secured revolving credit facility due October 2026 | Revolving Credit Facility
Debt Instrument
Interest expense, debt	$ 9.2	$ 6.4	$ 23.6	$ 14.7