Revenue - Summary of Revenues Disaggregated by Product Line (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Disaggregation Of Revenue [Line Items]
Revenue	$ 2,182.4	$ 1,936.0	$ 6,237.2	$ 5,864.5
Packaging
Disaggregation Of Revenue [Line Items]
Revenue	2,008.7	1,759.8	5,715.3	5,358.7
Paper
Disaggregation Of Revenue [Line Items]
Revenue	159.3	157.9	473.2	451.6
Corporate and Other
Disaggregation Of Revenue [Line Items]
Revenue	$ 14.4	$ 18.3	$ 48.7	$ 54.2