Revenue - Summary of Revenues Disaggregated by Product Line (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation Of Revenue [Line Items]
Revenue	$ 2,237.3	$ 1,879.9	$ 4,373.7	$ 3,687.0
Packaging
Disaggregation Of Revenue [Line Items]
Revenue	2,066.9	1,718.5	4,031.3	3,342.1
Paper
Disaggregation Of Revenue [Line Items]
Revenue	149.8	142.3	303.3	306.8
Corporate and Other
Disaggregation Of Revenue [Line Items]
Revenue	$ 20.6	$ 19.1	$ 39.1	$ 38.1