Other Expense, Net - Components of Other Expense, Net (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset disposals and write-offs		$ (38.9)	$ (26.5)	$ (25.0)
Facilities closure and other income (costs)	[1]	6.5	(19.1)	(0.3)
Acquisition and integration related costs	[2]	(0.6)	0.0	0.0
Other		(12.9)	(5.1)	(6.7)
Total		(54.8)	(50.7)	(32.7)
Jackson, Alabama Mill
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Conversion-related activities	[3]	(8.9)	0.0	0.0
Wallula, Washington Mill
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Conversion-related activities	[4]	$ 0.0	$ 0.0	$ (0.7)

[1] 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 corrugated products facilities, 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. For 2020, includes charges consisting of restructuring costs for paper administrative functions and closure costs related to corrugated products facilities, substantially all of which relates to the previously announced closure of the San Lorenzo, California facility during the second quarter of 2020, partially offset by income related to the sale of a closed corrugated products facility during the second quarter of 2020. For 2019, includes charges consisting of closure costs related to corrugated products facilities, partially offset by income from the sale of a building related to a closed corrugated products facility.

[2] Includes charges related to the December 2021 Advance Packaging Corporation acquisition.

[3] 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.

[4] Includes charges related to the discontinuation of production of uncoated free sheet and coated one-side white paper grades at the Wallula, Washington mill in the second quarter of 2018 and the conversion of the No. 3 paper machine to produce virgin kraft linerboard.