Long Term Debt - Schedule of carrying values and fair values of debt instruments (Details) - USD ($) $ in Millions		Mar. 31, 2025	Dec. 31, 2024
CNK [Member]
Debt Instrument [Line Items]
Fair value	[1]	$ 2,699.0	$ 2,903.7
CUSA [Member]
Debt Instrument [Line Items]
Fair value		$ 1,892.2	$ 1,902.1

[1] The fair value of the 4.50% convertible senior notes was $806.8 and $1,001.6 as of March 31, 2025 and December 31, 2024, respectively.