Segment Information - Analysis of Operations by Reportable Segment (Details) - USD ($) $ in Millions		3 Months Ended															12 Months Ended
		Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2014	Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Segment Reporting Information [Line Items]
Trade sales																	$ 5,741.7		$ 5,852.6		$ 3,665.3	[1]
Net sales		$ 1,390.9		$ 1,470.8		$ 1,454.3		$ 1,425.7		$ 1,434.0	$ 1,518.9		$ 1,468.4		$ 1,431.3		5,741.7		5,852.6		3,665.3
Operating Income (Loss)		175.9	[2]	219.4	[3]	197.6	[4]	157.1	[5]	173.2	188.4	[6]	180.2	[7]	160.9	[8]	750.0		702.7		481.9	[1]
Interest expense, net																	(85.5)		(88.4)	[9]	(58.3)	[1],[10]
Income before taxes																	664.5		614.3		423.6	[1]
Depreciation, amortization, and depletion																	356.5		381.0		201.8	[1]
Capital expenditures	[11]																314.5		420.2		234.4	[1]
Assets		5,284.6								5,272.8							5,284.6		5,272.8		5,196.2	[1]
Class action lawsuit settlement																	0.0		17.6	[12]	0.0
Write-Off of Deferred Financing Costs
Segment Reporting Information [Line Items]
Interest expense, net																			(1.5)
Packaging
Segment Reporting Information [Line Items]
Trade sales																	4,474.1		4,534.5		3,431.3	[1]
Operating Income (Loss)																	714.9	[13]	663.2	[14]	554.2	[1],[15]
Depreciation, amortization, and depletion																	297.3		323.0		190.2	[1]
Capital expenditures	[11]																250.3		362.1		222.2	[1]
Assets		4,027.9								4,105.3							4,027.9		4,105.3		3,988.5	[1]
Paper
Segment Reporting Information [Line Items]
Trade sales																	1,143.1		1,201.4		216.9	[1]
Operating Income (Loss)																	112.5	[16]	135.4		13.5	[1],[17]
Depreciation, amortization, and depletion																	54.9		50.6		9.1	[1]
Capital expenditures	[11]																58.5		51.7		10.0	[1]
Assets		976.5								968.6							976.5		968.6		938.4	[1]
Corporate and Other
Segment Reporting Information [Line Items]
Trade sales																	124.5		116.7		17.1	[1]
Operating Income (Loss)																	(77.4)	[18]	(95.9)	[19]	(85.8)	[1],[20]
Depreciation, amortization, and depletion																	4.3		7.4		2.5	[1]
Capital expenditures	[11]																5.7		6.4		2.2	[1]
Assets		280.2								198.9							280.2		198.9		269.3	[1]
Class action lawsuit settlement																			17.6
Boise Inc. | Packaging
Segment Reporting Information [Line Items]
Operating Income (Loss)																	4.1
Boise Inc. | Corporate and Other
Segment Reporting Information [Line Items]
Operating Income (Loss)																	9.3
DeRidder Restructuring Costs
Segment Reporting Information [Line Items]
Operating Income (Loss)		3.5		3.8		1.0		(10.3)		(18.0)	(26.0)		(17.8)		(4.0)
Acquisition Inventory Step-Up | Boise Inc. | Packaging
Segment Reporting Information [Line Items]
Operating Income (Loss)																					(18.0)
Acquisition Inventory Step-Up | Boise Inc. | Paper
Segment Reporting Information [Line Items]
Operating Income (Loss)																					(3.5)
Integration-Related and Other Costs | Boise Inc.
Segment Reporting Information [Line Items]
Operating Income (Loss)		$ (3.8)		(2.4)		$ (3.7)		$ (3.5)		$ (6.4)			$ (4.9)		$ (4.1)
Income before taxes											$ (4.5)
Integration-Related and Other Costs | Boise Inc. | Packaging
Segment Reporting Information [Line Items]
Operating Income (Loss)																					(1.4)
Integration-Related and Other Costs | Boise Inc. | Paper
Segment Reporting Information [Line Items]
Operating Income (Loss)																					1.9
Integration-Related and Other Costs | Boise Inc. | Corporate and Other
Segment Reporting Information [Line Items]
Operating Income (Loss)																					(17.9)
Nonrecurring Acquisition-Related Costs | Boise Inc. | Corporate and Other
Segment Reporting Information [Line Items]
Operating Income (Loss)																					(17.2)
Acquisition-Related Debt Financing Costs | Boise Inc. | Acquisition Financing Expense
Segment Reporting Information [Line Items]
Interest expense, net																					(10.5)
Acquisition-Related Debt Financing Costs | Boise Inc. | Write-Off of Deferred Financing Costs
Segment Reporting Information [Line Items]
Interest expense, net																					(1.1)
Intersegment Eliminations
Segment Reporting Information [Line Items]
Intersegment sales																	0.0		0.0		0.0	[1]
Intersegment Eliminations | Packaging
Segment Reporting Information [Line Items]
Intersegment sales																	3.2		5.8		0.4	[1]
Intersegment Eliminations | Paper
Segment Reporting Information [Line Items]
Intersegment sales																	0.0		0.0		0.0	[1]
Intersegment Eliminations | Corporate and Other
Segment Reporting Information [Line Items]
Intersegment sales																	133.8		144.9		28.0	[1]
Intersegment Eliminations | Intersegment Eliminations
Segment Reporting Information [Line Items]
Intersegment sales	[1]																				(28.4)
Operating Segments
Segment Reporting Information [Line Items]
Net sales																	5,741.7		5,852.6		3,665.3	[1]
Operating Segments | Packaging
Segment Reporting Information [Line Items]
Net sales																	4,477.3		4,540.3		3,431.7	[1]
Operating Segments | Paper
Segment Reporting Information [Line Items]
Net sales																	1,143.1		1,201.4		216.9	[1]
Operating Segments | Corporate and Other
Segment Reporting Information [Line Items]
Net sales																	258.3		261.6		45.1	[1]
Operating Segments | Intersegment Eliminations
Segment Reporting Information [Line Items]
Net sales	[1]																				(28.4)
Segment Reconciling Items
Segment Reporting Information [Line Items]
Intersegment sales																	(137.0)		(150.7)
Net sales																	(137.0)		(150.7)
Other Expense | DeRidder Restructuring Costs | Packaging
Segment Reporting Information [Line Items]
Operating Income (Loss)																			(65.8)
Other Expense | Integration-Related and Other Costs | Boise Inc. | Packaging
Segment Reporting Information [Line Items]
Operating Income (Loss)																			(4.9)
Other Expense | Integration-Related and Other Costs | Boise Inc. | Corporate and Other
Segment Reporting Information [Line Items]
Operating Income (Loss)																			(13.5)
Other Restructuring [Member] | Packaging
Segment Reporting Information [Line Items]
Operating Income (Loss)																	2.0
Mill at St. Helens, Oregon [Member]
Segment Reporting Information [Line Items]
Gain (Loss) on Disposition of Assets																	$ 6.7	[21]	$ 0.0		$ 0.0
Mill at St. Helens, Oregon [Member] | DeRidder Restructuring Costs
Segment Reporting Information [Line Items]
Operating Income (Loss)				$ 6.7

[1] On October 25, 2013, we acquired Boise Inc. (Boise). Our financial results include Boise subsequent to acquisition.

[2] Includes $3.5 million of income from DeRidder restructuring ($2.2 million after-tax or $0.02 per diluted share) and $3.8 million of integration-related and other costs ($2.6 million after-tax or $0.03 per diluted share).

[3] Includes $3.8 million of income from DeRidder restructuring ($2.3 million after-tax or $0.02 per diluted share) and $2.4 million of integration-related and other costs ($1.7 million after-tax or $0.02 per diluted share). Also includes $6.7 million gain from the sale of our paper mill site at St. Helens, Oregon ($4.4 million after tax or $0.05 per diluted share).

[4] Includes $1.0 million of income from DeRidder restructuring ($0.7 million after-tax or $0.01 per diluted share) and $3.7 million of integration-related and other costs ($2.3 million after-tax or $0.03 per diluted share). Gross profit has been revised to correct an error in the previous presentation totaling $6.0 million reclassified from "Selling, general, and administrative expenses" to "Cost of Sales" for the three months ended June 30, 2015.

[5] Includes $10.3 million of DeRidder restructuring charges ($6.6 million after-tax or $0.07 per diluted share) and $3.5 million of integration-related and other costs ($2.2 million after-tax or $0.02 per diluted share). Also includes a $3.6 million tax credit from the State of Louisiana related to our recent capital investment and the jobs retained at the DeRidder, Louisiana mill.

[6] Includes $26.0 million of DeRidder restructuring charges ($16.6 million after-tax or $0.17 per diluted share) and $4.5 million of integration-related and other costs ($2.9 million after-tax or $0.03 per diluted share).

[7] Includes $17.8 million of DeRidder restructuring charges ($11.2 million after-tax or $0.12 per diluted share) and $4.9 million of integration-related and other costs ($3.0 million after-tax or $0.03 per diluted share).

[8] Includes $17.6 million of costs accrued for the settlement of the Kleen Products LLC v Packaging Corp. of America et al class action lawsuit ($11.2 million after-tax or $0.11 per diluted share), $4.1 million of integration-related costs ($2.6 million after-tax or $0.03 per diluted share), and $4.0 million of DeRidder restructuring charges ($2.6 million after-tax or $0.02 per diluted share).

[9] Includes $1.5 million of expense related to the write-off of deferred financing costs in connection with the debt refinancing discussed in Note 10, Debt.

[10] Includes $10.5 million of expenses for financing the Boise acquisition and $1.1 million of expense for the write-off of deferred financing costs.

[11] Includes "Additions to property, plant, and equipment" and excludes cash used for "Acquisitions of businesses, net of cash acquired" as reported on our Consolidated Statements of Cash Flows.

[12] Includes $17.6 million of costs for the settlement of the Kleen Products LLC v Packaging Corp. of America et al class action lawsuit. See Note 19, Commitments, Guarantees, Indemnifications, and Legal Proceedings, for more information.

[13] Includes net charges of $2.0 million primarily related to restructuring activities at our mill in DeRidder, Louisiana and $4.1 million of Boise acquisition integration-related and other costs.

[14] Includes $65.8 million of costs related primarily to the conversion of the No. 3 newsprint machine at our DeRidder, Louisiana mill to produce lightweight linerboard and corrugating medium, and our exit from the newsprint business in September 2014. Includes $4.9 million of Boise acquisition integration-related and other costs.

[15] Includes $18.0 million of expense for the acquisition inventory step-up and $1.4 million of integration-related and other costs incurred in connection with the acquisition of Boise in fourth quarter 2013.

[16] In September 2015, we sold the remaining land, buildings, and equipment at our paper mill site in St. Helens, Oregon where we ceased paper production in December 2012. We recorded a $6.7 million gain on the sale.

[17] Includes $3.5 million of expense for acquisition inventory step-up and $1.9 million of income for integration-related and other costs.

[18] Includes $9.3 million of Boise acquisition integration-related and other costs. These costs primarily relate to professional fees, severance, retention, relocation, travel, and other integration-related costs.

[19] Includes $13.5 million of Boise acquisition integration-related and other costs and $17.6 million of costs for the settlement of the Kleen Products LLC v Packaging Corp. of America et al class action lawsuit. See Note 19, Commitments, Guarantees, Indemnifications, and Legal Proceedings, for more information.

[20] Includes $17.2 million of acquisition-related costs and $17.9 million of integration-related and other costs.

[21] In September 2015, we sold the remaining land, buildings, and equipment at our paper mill site in St. Helens, Oregon where we ceased paper production in December 2012. We recorded a $6.7 million gain on the sale.