Other Expense, Net - Components of Other Income (Expense), Net (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset disposals and write-offs		$ (13.8)	$ (9.0)	$ (26.4)	$ (19.9)
Acquisition-related, facilities closure and other income	[1]	0.5	5.5	0.1	3.4
Other		(1.3)	(2.0)	(3.5)	(8.9)
Total		(16.3)	(7.9)	(31.9)	(28.3)
Jackson, Alabama Mill
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Conversion-related activities	[2]	$ (1.7)	$ (2.4)	$ (2.1)	$ (2.9)

[1] For 2022, includes income primarily consisting of insurance proceeds received for a natural disaster at one of the corrugated products facilities, partially offset by closure costs related to corrugated products facilities and acquisition and integration costs related to the December 2021 Advance Packaging Corporation acquisition. For 2021, includes income primarily consisting of an adjustment of the required asset retirement obligation related to the 2020 closure of the San Lorenzo, California facility, a gain on sale of transportation assets, and insurance proceeds received for a natural disaster at one of the corrugated products facilities, partially offset by closure costs related to corrugated products facilities.

[2] Includes charges related to the announced discontinuation of production of uncoated freesheet paper grades on the No. 3 machine at the Jackson, Alabama mill in the first quarter of 2021 associated with the permanent conversion of the machine to produce linerboard and other paper-to-containerboard conversion related activities.