Debt and Credit Arrangements - Notes Interest Accretion Schedule (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Nov. 06, 2017
Debt Instrument
2024 Notes, 1.0% contractual interest coupon, 1.5% for 2022	$ 271.9	$ 28.8	$ 10.7
2024 Notes, financing costs amortization	17.2	2.9	8.3
Convertible Debt | Convertible notes due November 2024
Debt Instrument
2024 Notes, 1.0% contractual interest coupon, 1.5% for 2022	2.4	4.0	2.6
2024 Notes, financing costs amortization	$ 1.0	$ 0.9	$ 0.9
Debt instrument stated interest rate (percent)	1.00%	1.50%		1.00%