Revenue - Summary of Revenues Disaggregated by Product Line (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Disaggregation Of Revenue [Line Items]
Revenue	$ 1,807.2	$ 1,708.7
Packaging
Disaggregation Of Revenue [Line Items]
Revenue	1,623.6	1,467.5
Paper
Disaggregation Of Revenue [Line Items]
Revenue	164.6	217.4
Corporate and Other
Disaggregation Of Revenue [Line Items]
Revenue	$ 19.0	$ 23.8

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details