Packaging Corporation of America (PKG) 10-K 26 Feb 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Feb. 19, 2016	Jun. 30, 2015
Document and Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Trading Symbol	PKG
Entity Registrant Name	PACKAGING CORP OF AMERICA
Entity Central Index Key	75,677
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		94,251,749
Entity Public Float			$ 6,119,141,093

Consolidated Statements of Inco

Consolidated Statements of Income and Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2013
Income Statement [Abstract]
Net sales	$ 5,741.7	$ 5,852.6		$ 3,665.3
Cost of sales	(4,533.7)	(4,623.1)		(2,797.8)
Gross profit	1,208	1,229.5		867.5
Selling, general, and administrative expenses	(451.3)	(469.5)		(326.6)
Other expense, net	(6.7)	(57.3)		(59)
Income from operations	750	702.7		481.9	[1]
Interest expense, net	(85.5)	(88.4)	[2]	(58.3)	[1],[3]
Income before taxes	664.5	614.3		423.6	[1]
(Provision) benefit for income taxes	(227.7)	(221.7)		17.7
Net income	$ 436.8	$ 392.6		$ 441.3
Net income per common share
Basic (US$ per share)	$ 4.47	$ 3.99		$ 4.57
Diluted (US$ per share)	4.47	3.99		4.52
Dividends declared per common share (US$ per share)	$ 2.20	$ 1.60		$ 1.51
Statement of Comprehensive Income:
Net income	$ 436.8	$ 392.6		$ 441.3
Foreign currency translation adjustment	2.7	(2.6)		(0.1)
Reclassification adjustments to cash flow hedges included in net income, net of tax of $2.2 million, $2.2 million, and $2.2 million for 2015, 2014, and 2013, respectively	3.5	3.5		3.5
Amortization of pension and postretirement plans actuarial loss and prior service cost, net of tax of $5.6 million, $2.8 million, and $8.5 million for 2015, 2014, and 2013, respectively	8.8	4.2		13.4
Changes in unfunded employee benefit obligations, net of tax of $8.9 million, $59.2 million, and $20.4 million for 2015, 2014, and 2013, respectively	14	(94)		32.2
Other comprehensive income (loss)	29	(88.9)		49
Comprehensive income	$ 465.8	$ 303.7		$ 490.3
[1]	On October 25, 2013, we acquired Boise Inc. (Boise). Our financial results include Boise subsequent to acquisition.
[2]	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.
[3]	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.

Consolidated Statements of Inc3

Consolidated Statements of Income and Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Reclassification adjustment for cash flow hedges included in net income, tax	$ 2.2	$ 2.2	$ 2.2
Amortization of pension and postretirement plans actuarial loss and prior service cost, tax	5.6	2.8	8.5
Changes in unfunded employee benefit obligations, tax	$ 8.9	$ (59.2)	$ 20.4

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 184.2	$ 124.9
Accounts receivable, net of allowance for doubtful accounts and customer deductions of $10.3 million and $11.3 million as of December 31, 2015 and 2014, respectively	636.5	646.1
Inventories	676.8	664.9
Prepaid expenses and other current assets	28.8	61.9
Federal and state income taxes receivable	28.2	5.1
Total current assets	1,554.5	1,502.9
Property, plant, and equipment, net	2,832.1	2,857.6
Goodwill	544	546.8
Intangible assets, net	270.8	293.5
Other long-term assets	83.2	72
Total assets	5,284.6	5,272.8
Current liabilities:
Current maturities of long-term debt	6.5	6.5
Capital lease obligations	1.2	1.1
Accounts payable	294.2	330.5
Dividends payable	53.4	39.4
Accrued liabilities	193.5	220
Accrued interest	13.1	13.5
Total current liabilities	561.9	611
Long-term liabilities:
Long-term debt	2,302.7	2,348.9
Capital lease obligations	21.6	22.8
Deferred income taxes	347	334.2
Compensation and benefits	358.6	361.7
Other long-term liabilities	59.5	72.8
Total long-term liabilities	$ 3,089.4	$ 3,140.4
Commitments and contingent liabilities
Stockholders' equity:
Common stock, par value $0.01 per share, 300.0 million shares authorized, 96.1 million and 98.4 million shares issued as of December 31, 2015 and 2014, respectively	$ 1	$ 1
Additional paid in capital	439.9	432.1
Retained earnings	1,317.3	1,242.2
Accumulated other comprehensive loss	(124.9)	(153.9)
Total stockholders' equity	1,633.3	1,521.4
Total liabilities and stockholders' equity	$ 5,284.6	$ 5,272.8

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Allowance for doubtful accounts and customer deductions	$ 10.3	$ 11.3
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	96,100,000	98,400,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash Flows from Operating Activities:
Net income		$ 436.8	$ 392.6	$ 441.3
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion, and amortization of intangibles and deferred financing costs		364.3	390.8	217.9
Share-based compensation expense		18.2	15.6	14.8
Deferred income tax provision (benefit)		1.7	2.6	(160.3)
Alternative energy tax credits		0	0	76.3
Loss on disposals of property, plant, and equipment		0.5	7	9.4
Pension and post retirement benefits expense, net of contributions		31.2	25.4	18.5
Other, net		(20.3)	(0.9)	(1)
Decrease (increase) in assets —
Accounts receivable		9.5	(8.5)	(31.2)
Inventories		(11.9)	(72.4)	25
Prepaid expenses and other current assets		4.1	(5.1)	(1.9)
Increase (decrease) in liabilities —
Accounts payable		(37.3)	(36)	54.2
Accrued liabilities		(15.5)	7	(22.1)
Federal and state income tax payable/receivable		(18.7)	18	(32.7)
Net cash provided by operating activities		762.6	736.1	608.2
Cash Flows from Investing Activities:
Additions to property, plant, and equipment	[1]	(314.5)	(420.2)	(234.4)	[2]
Proceeds from sale of a business		23	0	0
Acquisitions of businesses, net of cash acquired		0	(20.5)	(1,174.5)
Additions to other long term assets		(12.3)	(12.5)	(3.1)
Other		5.7	2.1	0.6
Net cash used for investing activities		(298.1)	(451.1)	(1,411.4)
Cash Flows from Financing Activities:
Proceeds from issuance of debt		0	398.9	1,998.1
Repayments of debt		(47.6)	(592.5)	(1,074.8)
Financing costs paid		0	(3.4)	(19.4)
Common stock dividends paid		(200.8)	(157.4)	(109.1)
Repurchases of common stock		(154.7)	0	(7.8)
Proceeds from exercise of stock options		0	3.7	2.9
Excess tax benefits from stock-based awards		6	12.2	7.8
Shares withheld to cover employee restricted stock taxes		(8.7)	(13.2)	(11)
Other		0.6	0.6	0.1
Net cash (used for) provided by financing activities		(405.2)	(351.1)	786.8
Net increase (decrease) in cash and cash equivalents		59.3	(66.1)	(16.4)
Cash and cash equivalents, beginning of year		124.9	191	207.4
Cash and cash equivalents, end of year		$ 184.2	$ 124.9	$ 191
[1]	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.
[2]	On October 25, 2013, we acquired Boise Inc. (Boise). Our financial results include Boise subsequent to acquisition.

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock	Treasury Stock	Additional Paid in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance (in shares) at Dec. 31, 2012		98,143,000	0
Beginning Balance at Dec. 31, 2012	$ 1,008.3	$ 1	$ 0	$ 378.8	$ 742.5	$ (114)
Common stock repurchases and retirements (in shares)	(171,263)	(171,000)	0
Common stock repurchases and retirements	$ (7.8)	$ 0	$ 0	(1.1)	(6.7)	0
Common stock withheld and retired to cover taxes on vested stock awards (in shares)		(224,000)	0
Common stock withheld and retired to cover taxes on vested stock awards	(11)	$ 0	$ 0	(1.4)	(9.6)	0
Common stock dividends declared	(148.4)	$ 0	$ 0	0	(148.4)	0
Restricted stock grants and cancellations (in shares)		297,000	0
Restricted stock grants and cancellations	6.9	$ 0	$ 0	6.9	0	0
Exercise of stock options (in shares)		127,000	0
Exercise of stock options	3.7	$ 0	$ 0	3.7	0	0
Share-based compensation expense	14.8	0	0	14.8	0	0
Comprehensive income	490.3	$ 0	$ 0	0	441.3	49
Ending Balance (in shares) at Dec. 31, 2013		98,172,000	0
Ending Balance at Dec. 31, 2013	$ 1,356.8	$ 1	$ 0	401.7	1,019.1	(65)
Common stock repurchases and retirements (in shares)	0
Common stock repurchases and retirements	$ 0
Common stock withheld and retired to cover taxes on vested stock awards (in shares)		(183,000)	0
Common stock withheld and retired to cover taxes on vested stock awards	(13.2)	$ 0	$ 0	(1.2)	(12)	0
Common stock dividends declared	(157.5)	$ 0	$ 0	0	(157.5)	0
Restricted stock grants and cancellations (in shares)		228,000	0
Restricted stock grants and cancellations	9.7	$ 0	$ 0	9.7	0	0
Exercise of stock options (in shares)		151,000	0
Exercise of stock options	6.3	$ 0	$ 0	6.3	0	0
Share-based compensation expense	15.6	0	0	15.6	0	0
Comprehensive income	303.7	$ 0	$ 0	0	392.6	(88.9)
Ending Balance (in shares) at Dec. 31, 2014		98,368,000	0
Ending Balance at Dec. 31, 2014	$ 1,521.4	$ 1	$ 0	432.1	1,242.2	(153.9)
Common stock repurchases and retirements (in shares)	(2,326,493)	(2,326,000)	0
Common stock repurchases and retirements	$ (154.7)	$ 0	$ 0	(15.6)	(139.1)	0
Common stock withheld and retired to cover taxes on vested stock awards (in shares)		(131,000)	0
Common stock withheld and retired to cover taxes on vested stock awards	(8.7)	$ 0	$ 0	(0.8)	(7.9)	0
Common stock dividends declared	(214.7)	$ 0	$ 0	0	(214.7)	0
Restricted stock grants and cancellations (in shares)		218,000	0
Restricted stock grants and cancellations	6	$ 0	$ 0	6	0	0
Share-based compensation expense	18.2	0	0	18.2	0	0
Comprehensive income	465.8	$ 0	$ 0	0	436.8	29
Ending Balance (in shares) at Dec. 31, 2015		96,129,000	0
Ending Balance at Dec. 31, 2015	$ 1,633.3	$ 1	$ 0	$ 439.9	$ 1,317.3	$ (124.9)

Nature of Operations and Basis

Nature of Operations and Basis of Presentation	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations and Basis of Presentation	Nature of Operations and Basis of Presentation Packaging Corporation of America ("we," "us," "our," "PCA," or the "Company") was incorporated on January 25, 1999. In April 1999, PCA acquired the containerboard and corrugated packaging products business of Pactiv Corporation (Pactiv), formerly known as Tenneco Packaging, Inc., a wholly owned subsidiary of Tenneco Inc. On October 25, 2013 , PCA acquired Boise Inc. (Boise). For more information, see Note 3 , Acquisitions and Dispositions . After the acquisition of Boise, we became a large diverse manufacturer of both packaging and paper products. We are headquartered in Lake Forest, Illinois and we operate primarily in the United States with some converting and distribution operations in Canada. We have approximately 13,000 employees. We report our businesses in three reportable segments: Packaging, Paper, and Corporate and Other. Our Packaging segment produces a wide variety of corrugated packaging products. The Paper segment manufactures and sells a range of papers, including communication-based papers, and pressure sensitive papers (collectively, white papers), and market pulp. Corporate and other includes support staff services and related assets and liabilities, transportation assets, and activity related to other ancillary support operations. For more information about our segments, see Note 18 , Segment Information . In these consolidated financial statements, certain amounts in prior periods' consolidated financial statements have been reclassified to conform with the current period presentation. Effective December 31, 2015, the Company adopted Accounting Standards Update 2015-17, Balance Sheet Classification of Deferred Taxes . The guidance eliminates the requirement to classify deferred taxes between current and noncurrent and requires that all deferred tax assets and liabilities, along with any related valuation allowance, be classified as noncurrent on the balance sheet. Related to the adoption of this guidance, we reclassified $75.7 million from current assets to long term liabilities on our December 31, 2014 Consolidated Balance Sheet to conform with the current period presentation. The consolidated financial statements include the accounts of PCA and its majority-owned subsidiaries after elimination of intercompany balances and transactions. Boise's results are included in our results subsequent to October 25, 2013 , the date of acquisition.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions about future events. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities, and reported amounts of revenues and expenses. These estimates and assumptions are based on management's best estimates and judgment. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment. We adjust such estimates and assumptions when facts and circumstances dictate. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Changes in these estimates will be reflected in the consolidated financial statements in future periods. Revenue Recognition We recognize revenue when the following criteria are met: persuasive evidence of an agreement exists, the customer takes title and assumes risk and rewards of ownership or services have been rendered, our price to the buyer is fixed or determinable, and collectability is reasonably assured. The timing of revenue recognition is dependent on transfer of title which is normally either on exit from our plants (i.e., shipping point) or on arrival at customer’s location (i.e., destination point). Shipping and handling billings to a customer are included in net sales. Shipping and handling costs, such as freight to our customers' destinations, are included in cost of sales. We present taxes collected from customers and remitted to governmental authorities on a net basis in our Consolidated Statements of Income. Planned Major Maintenance Costs The Company accounts for its planned major maintenance activities in accordance with ASC 360, "Property, Plant, and Equipment," using the deferral method. All maintenance costs incurred during the year are expensed in the year in which the maintenance activity occurs. Share-Based Compensation We recognize compensation expense for awards granted under the PCA long-term equity incentive plans based on the fair value on the grant date. We recognize the cost of the equity awards expected to vest over the period the awards vest. See Note 13 , Share-Based Compensation , for more information. Research and Development Research and development costs are expensed as incurred. The amount charged to expense was $13.1 million , $12.3 million , and $11.5 million for the years ended December 31, 2015 , 2014 , and 2013 , respectively. Foreign Currency Local currencies are the functional currencies for our operations outside the United States. Assets and liabilities are remeasured into U.S. dollars using the exchange rates as of the Consolidated Balance Sheet date. Revenue and expense items are remeasured into U.S. dollars using an average exchange rate prevailing during the period. Any resulting translation adjustments are recorded in the Consolidated Statements of Comprehensive Income. The foreign exchange gain (loss) resulting from remeasuring transactions into the functional currencies is reported in the Consolidated Statements of Income. Cash and Cash Equivalents Cash and cash equivalents include all cash balances and highly liquid investments with a stated maturity of three months or less. Cash equivalents are stated at cost, which approximates market. Cash and cash equivalents totaled $184.2 million and $124.9 million at December 31, 2015 and 2014 , respectively, which included cash equivalents of $140.9 million and $79.9 million , respectively. At December 31, 2015 and 2014 , we had $3.1 million and $10.4 million , respectively, of cash at our operations outside the United States. Trade Accounts Receivable, Allowance for Doubtful Accounts, and Customer Deductions Trade accounts receivable are stated at the amount we expect to collect. The collectability of our accounts receivable is based upon a combination of factors. In circumstances where a specific customer is unable to meet its financial obligations to PCA (e.g., bankruptcy filings, substantial downgrading of credit sources), a specific reserve for bad debts is recorded against amounts due to the Company to reduce the net recorded receivable to the amount the Company reasonably believes will be collected. For all other customers, reserves for bad debts are recognized based on historical collection experience. If collection experience deteriorates (i.e., higher than expected defaults or an unexpected material adverse change in a major customer’s ability to meet its financial obligations to the Company), the estimate of the recoverability of amounts due could be reduced by a material amount. We periodically review our allowance for doubtful accounts and adjustments to the valuation allowance are recorded as income or expense. Trade accounts receivable balances that remain outstanding after we have used reasonable collection efforts are written off through a charge to the valuation allowance and a credit to accounts receivable. At December 31, 2015 and 2014 , the allowance for doubtful accounts was $3.9 million and $4.9 million , respectively. The customer deductions reserve represents the estimated amount required for customer returns, allowances, and earned discounts. Based on the Company’s experience, customer returns, allowances, and earned discounts have averaged approximately 1% of gross selling price. Accordingly, PCA reserves 1% of its open customer accounts receivable balance for these items. The reserves for customer deductions of $6.4 million for both December 31, 2015 and 2014 , respectively, are also included as a reduction of the accounts receivable balance. Derivative Instruments and Hedging Activities The Company records its derivatives, if any, in accordance with ASC 815, "Derivatives and Hedging." The guidance requires the Company to recognize derivative instruments as either assets or liabilities on the balance sheet at fair value. The accounting for changes in the fair value of a derivative depends on the intended use and designation of the derivative instrument. For a derivative designated as a fair value hedge, the gain or loss on the derivative is recognized in earnings in the period of change at fair value together with the offsetting gain or loss on the hedged item. For a derivative instrument designated as a cash flow hedge, the effective portion of the derivative’s gain or loss is initially reported as a component of accumulated other comprehensive income (loss) (AOCI) and is subsequently recognized in earnings when the hedged exposure affects earnings. The ineffective portion of the gain or loss is recognized in earnings. We were not party to any derivative-based arrangements at December 31, 2015 and 2014 . Fair Value Measurements PCA measures the fair value of its financial instruments in accordance with ASC 820, "Fair Value Measurements and Disclosures." The guidance defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. It is determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, ASC 820 establishes the following hierarchy that prioritizes the inputs to valuation methodologies used to measure fair value: Level 1 — Valuations based on quoted prices for identical assets and liabilities in active markets. Level 2 — Valuations based on observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets and liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data. Level 3 — Valuations based on unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. Financial instruments measured at fair value on a recurring basis include the fair value of our pension and postretirement benefit assets and liabilities. See Note 11 , Employee Benefit Plans and Other Postretirement Benefits for more information. Other assets and liabilities measured and recognized at fair value on a nonrecurring basis include assets acquired and liabilities assumed in acquisitions and our asset retirement obligations. Given the nature of these assets and liabilities, evaluating their fair value from the perspective of a market participant is inherently complex. Assumptions and estimates about future values can be affected by a variety of internal and external factors. Changes in these factors may require us to revise our estimates and could require us to retroactively adjust provisional amounts that we recorded for the fair values of assets acquired and liabilities assumed in connection with business combinations. These adjustments could have a material effect on our financial condition and results of operations. See Note 3 , Acquisitions and Dispositions , and Note 12 , Asset Retirement Obligations , for more information. Inventory Valuation We value our raw materials, work in process, and finished goods inventories using lower of cost, as determined by the average cost method, or market. Supplies and materials are valued at the first-in, first-out (FIFO) or average cost methods. The components of inventories were as follows (dollars in millions): December 31 2015 2014 Raw materials $ 260.6 $ 261.9 Work in process 14.2 11.3 Finished goods 189.7 216.3 Supplies and materials 212.3 175.4 Inventories $ 676.8 $ 664.9 Property, Plant, and Equipment Property, plant, and equipment are recorded at cost. Cost includes expenditures for major improvements and replacements and the amount of interest cost associated with significant capital additions. Repairs and maintenance costs are expensed as incurred . When property and equipment are retired, sold, or otherwise disposed of, the asset's carrying amount and related accumulated depreciation are removed from the accounts and any gain or loss is included in "Net income" in our Consolidated Statements of Income. Property, plant, and equipment consisted of the following (dollars in millions): December 31 2015 2014 Land and land improvements $ 146.4 $ 143.5 Buildings 640.9 654.6 Machinery and equipment 4,747.1 4,508.0 Construction in progress 119.1 154.8 Other 61.3 54.5 Property, plant, and equipment, at cost 5,714.8 5,515.4 Less accumulated depreciation (2,882.7 ) (2,657.8 ) Property, plant, and equipment, net $ 2,832.1 $ 2,857.6 The amount of interest capitalized from construction in progress was $2.0 million , $2.8 million , and $1.7 million for the years ended December 31, 2015 , 2014 , and 2013 , respectively. Depreciation is computed on the straight-line basis over the estimated useful lives of the related assets. Assets under capital leases are depreciated on the straight-line method over the term of the lease or the useful life, if shorter. The following lives are used for the various categories of assets: Buildings and land improvements 5 to 40 years Machinery and equipment 3 to 25 years Trucks and automobiles 3 to 10 years Furniture and fixtures 3 to 20 years Computers and hardware 3 to 10 years Leasehold improvements Period of the lease or useful life, if shorter The amount of depreciation expense was $323.0 million , $348.2 million , and $191.2 million for the years ended December 31, 2015 , 2014 , and 2013 , respectively. During the years ended December 31, 2015 and 2014 , we recognized $9.0 million and $42.0 million , respectively, of incremental depreciation expense primarily related to shortening the useful lives of assets related to the restructuring at the DeRidder, Louisiana, mill. Pursuant to the terms of an industrial revenue bond, title to certain property, plant, and equipment was transferred to a municipal development authority in 2009 in order to receive a property tax abatement. The title of these assets will revert back to PCA upon retirement or cancellation of the bond. The assets are included in the consolidated balance sheet under the caption "Property, plant, and equipment, net" as all risks and rewards remain with the Company. Leases We assess lease classification as either capital or operating at lease inception or upon modification. We lease some of our locations, as well as other property and equipment, under operating leases. For purposes of determining straight-line rent expense, the lease term is calculated from the date of possession of the facility, including any periods of free rent and any renewal option periods that are reasonably assured of being exercised. Long-Lived Asset Impairment Long-lived assets other than goodwill and other intangibles are reviewed for impairment in accordance with provisions of ASC 360, "Property, Plant and Equipment." In the event that facts and circumstances indicate that the carrying amount of any long-lived assets may be impaired, an evaluation of recoverability is performed. If an evaluation is required, the estimated future undiscounted cash flows associated with the asset (or group of assets) is compared to the assets (or group of assets) carrying amount to determine if a write-down to fair value is required. Goodwill and Intangible Assets The Company has capitalized certain intangible assets, primarily goodwill, customer relationships, and trademarks and trade names, based on their estimated fair value at the date of acquisition. Amortization is provided for customer relationships on a straight-line basis over periods ranging from ten to 40 years, and trademarks and trade names over periods ranging from three to 20 years. Goodwill, which amounted to $544.0 million and $546.8 million for the years ended December 31, 2015 and 2014 , respectively, is not amortized but is subject to an annual impairment test in accordance with ASC 350, "Intangibles - Goodwill and Other." We test goodwill for impairment annually in the fourth quarter or sooner if events or changes in circumstances indicate that the carrying value of the asset may exceed fair value. Additionally, we evaluate the remaining useful lives of our finite-lived purchased intangible assets to determine whether any adjustments to the useful lives are necessary. The Company concluded that none of the goodwill or intangible assets were impaired in the 2015 , 2014 , and 2013 annual impairment tests. See Note 8 , Goodwill and Intangible Assets for additional information. Pension and Postretirement Benefits Several estimates and assumptions are required to record pension costs and liabilities, including discount rate, return on assets, and longevity and service lives of employees. We review and update these assumptions annually unless a plan curtailment or other event occurs, requiring we update the estimates on an interim basis. While we believe the assumptions used to measure our pension and postretirement benefit obligations are reasonable, differences in actual experience or changes in assumptions may materially affect our pension and postretirement benefit obligations and future expense. See Note 11 , Employee Benefit Plans and Other Postretirement Benefits , for additional information. For postretirement health care plan accounting, the Company reviews external data and its own historical trends for health care costs to determine the health care cost trend rate assumption. Environmental Matters Environmental expenditures that extend the life of the related property or mitigate or prevent future environmental contamination are capitalized. Liabilities are recorded for environmental contingencies when such costs are probable and reasonably estimable. These liabilities are adjusted as further information develops or circumstances change. Environmental expenditures related to existing conditions resulting from past or current operations from which no current or future benefit is discernible are expensed as incurred. Asset Retirement Obligations The Company accounts for its retirement obligations related predominantly to landfill closure, wastewater treatment pond dredging, closed-site monitoring costs, and certain leasehold improvements under ASC 410, "Asset Retirement and Environmental Obligations," which requires recognition of legal obligations associated with the retirement of long-lived assets whether these assets are owned or leased. These legal obligations are recognized at fair value at the time that the obligations are incurred. When we record the liability, we capitalize the cost by increasing the carrying amount of the related long-lived asset which is amortized to expense over the useful life of the asset. See Note 12 , Asset Retirement Obligations , for additional information. Deferred Financing Costs PCA has capitalized certain costs related to obtaining its financing. These costs are amortized to interest expense using the effective interest rate method over the terms of the related financing, which range from five to ten years. Unamortized deferred financing costs of $12.3 million and $14.1 million at December 31, 2015 and 2014 , respectively, were recorded in "Other long-term assets" on our Consolidated Balance Sheets. Cutting Rights and Fiber Farms We lease the cutting rights to approximately 83,000 acres of timberland and we lease 9,000 acres of land where we operate fiber farms as a source of future fiber supply. For our cutting rights and fiber farms, we capitalized the annual lease payments and reforestation costs associated with these leases. Costs are recorded as depletion when the timber or fiber is harvested and used in operations or sold to customers. Capitalized long-term lease costs for our cutting rights and fiber farms, primarily recorded in "Other long-term assets" on our Consolidated Balance Sheet, were $40.2 million and $38.0 million as of December 31, 2015 and 2014 , respectively. The amount of depletion expense was $7.0 million , $7.3 million , and $2.5 million for the years ended December 31, 2015 , 2014 , and 2013 , respectively. Deferred Software Costs PCA capitalizes costs related to the purchase and development of software which is used in its business operations. The costs attributable to these software systems are amortized over their estimated useful lives based on various factors such as the effects of obsolescence, technology, and other economic factors. Net capitalized software costs recorded in "Other long-term assets" on our Consolidated Balance Sheets were $6.9 million and $6.8 million for the years ended December 31, 2015 and 2014 , respectively. Software amortization expense was $3.0 million , $2.9 million , and $1.1 million for the years ended December 31, 2015 , 2014 , and 2013 , respectively. Income Taxes PCA utilizes the liability method of accounting for income taxes whereby it recognizes deferred tax assets and liabilities for the future tax consequences of temporary differences between the tax basis of assets and liabilities and their reported amounts in the financial statements. Deferred tax assets will be reduced by a valuation allowance if, based upon management’s estimates, it is more likely than not that a portion of the deferred tax assets will not be realized in a future period. The estimates utilized in the recognition of deferred tax assets are subject to revision in future periods based on new facts or circumstances. PCA’s practice is to recognize interest and penalties related to unrecognized tax benefits in income tax expense. Trade Agreements PCA regularly trades containerboard with other manufacturers primarily to reduce shipping costs. These agreements are entered into with other producers on an annual basis, pursuant to which both parties agree to ship an identical number of tons of containerboard to each other within the agreement period. These agreements lower transportation costs by allowing each party’s containerboard mills to ship containerboard to the other party’s closer corrugated products plant. PCA tracks each shipment to ensure that the other party’s shipments to PCA match PCA’s shipments to the other party during the agreement period. Such transfers are possible because containerboard is a commodity product with no distinguishing product characteristics. These transactions are accounted for at carrying value, and revenue is not recorded as the transactions do not represent the culmination of an earnings process. The transactions are recorded into inventory accounts, and no sale or income is recorded until such inventory is converted to a finished product and sold to an end-use customer. New and Recently Adopted Accounting Standards In November 2015, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2015-17 (Topic 740): Balance Sheet Classification of Deferred Taxes. The new guidance conforms U.S. Generally Accepted Accounting Principles (GAAP) and International Financial Reporting Standards (IFRS) and eliminates the requirement to classify deferred taxes between current and noncurrent. The ASU requires all deferred tax assets and liabilities, along with any related valuation allowance, be classified as noncurrent on the balance sheet. We early adopted this guidance as of December 31, 2015. Related to the adoption of this guidance, we reclassified $75.7 million from current assets to long term liabilities on our December 31, 2014 Consolidated Balance Sheet to conform with the current period presentation. In July 2015, the FASB issued ASU 2015-11 (Topic 330): Simplifying the Measurement of Inventory, as part of its simplification initiative. Under the ASU, inventory is measured at the "lower of cost and net realizable value," which eliminates the other two options that currently exist for "market," including replacement cost and net realizable value less an approximately normal profit margin. No other changes were made to the current guidance on inventory measurement. The ASU is effective January 1, 2017, and we we do not expect the adoption of this update to have a material effect on our financial position or results of operations. In May 2015, the FASB issued ASU 2015-07 (Topic 820): Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent) , which removes the requirement to categorize within the fair value hierarchy all investments for which fair value is measured using the net asset value per share practical expedient. Further, the guidance removes the requirement to make certain disclosures for all investments that are eligible to be measured at fair value using the net asset value per share practical expedient. This ASU is effective for annual and interim periods beginning after December 15, 2015, and requires the new guidance be applied retrospectively to all prior periods presented. We do not believe the adoption of this update will have a material effect on our financial position and results of operations. In April 2015, the FASB issued ASU 2015-03 (Topic 835): Simplifying the Presentation of Debt Issuance Costs . This ASU conforms the presentation of debt issuance costs with that required for debt discounts under U.S. GAAP. Under the ASU, debt issuance costs are presented in the balance sheet as a direct deduction from the related debt liability rather than as an asset. The guidance is effective for annual and interim reporting periods beginning after December 15, 2015, and requires the new guidance be applied retrospectively to all prior periods presented. We do not believe the adoption of this update will have a material effect on our financial position and results of operations. In February 2015, the FASB issued ASU 2015-02 (Topic 810): Amendments to the Consolidation Analysis . This ASU makes targeted amendments to the current consolidation guidance and affects both the variable interest entity and voting interest entity consolidation models. The guidance is effective for annual reporting periods beginning after December 15, 2015. We do not believe the adoption of this update will have a material effect on our financial position and results of operations. In May 2014, the FASB issued ASU 2014-09 (Topic 606): Revenue from Contracts with Customers . This ASU amends the guidance for revenue recognition to replace numerous, industry-specific requirements and converges areas under this topic with those of the International Financial Reporting Standards. The ASU implements a five-step process for customer contract revenue recognition that focuses on transfer of control, as opposed to transfer of risk and rewards. The amendment also requires enhanced disclosures regarding the nature, amount, timing, and uncertainty of revenues and cash flows from contracts with customers. Entities can transition to the standard either retrospectively or as a cumulative-effect adjustment as of the date of adoption. In August 2015, the FASB issued ASU 2015-14: Revenue From Contracts with Customers (Topic 606): Deferral of the Effective Date. This ASU defers the effective date of the revenue standard, ASU 2014-09, by one year so that it is now effective for reporting periods beginning after December 15, 2017. We are still assessing the impact of ASU 2014-09, but we do not expect it to have a material effect on our financial position or results of operations. There were no other accounting standards recently issued that had or are expected to have a material impact on our financial position or results of operations.

Acquisitions and Dispositions

Acquisitions and Dispositions	12 Months Ended
	Dec. 31, 2015
Business Combinations [Abstract]
Acquisitions and Dispositions	Acquisitions and Dispositions Sale of European and Mexican Operations On April 1, 2015, we completed the sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico for approximately $ 23.0 million . The sale included three locations in Europe and two locations in Mexico. Sales, net income, and total assets of these locations are not material to our consolidated financial position or results of operations in any period presented. The gain on the sale was insignificant. Crockett Packaging Acquisition On April 28, 2014, we acquired the assets of Crockett Packaging, a corrugated products manufacturer, for $21.2 million , before $0.7 million of working capital adjustments. The assets included a corrugated plant and a sheet plant in Southern California. Sales and total assets of the acquired company are not material to our overall sales and total assets. Operating results of the acquired assets subsequent to April 28, 2014, are included in our Packaging segment's operating results. In connection with the acquisition, we allocated the purchase price to the assets acquired and liabilities assumed based on estimates of the fair value at the date of the acquisition. Boise Acquisition On October 25, 2013 , we acquired 100% of the outstanding stock and voting equity interests of Boise for $2.1 billion including the assumption of debt. We paid $12.55 per share to shareholders, or $1.2 billion , net of $121.7 million of cash acquired, and assumed the fair value of Boise's debt, of $829.8 million . During the year ended December 31, 2014 we recorded approximately $6.4 million of purchase price adjustments that increased goodwill. These adjustments related primarily to a true-up to the valuation of fixed assets, the associated impact to income tax liabilities, and residual goodwill. Boise's financial results are included in our Packaging, Paper, and Corporate and Other segments from the date of acquisition. For more information, see Note 18 , Segment Information .

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The following table sets forth the computation of basic and diluted income per common share for the periods presented (dollars and shares in millions, except per share data). Year Ended December 31 2015 2014 2013 Numerator: Net income $ 436.8 $ 392.6 $ 441.3 Less: distributed and undistributed earnings allocated to participating securities (5.2 ) (5.7 ) — Net income attributable to common shareholders $ 431.6 $ 386.9 $ 441.3 Denominator: Weighted average basic common shares outstanding 96.6 97.0 96.6 Effect of dilutive securities 0.1 0.1 0.9 Diluted common shares outstanding 96.7 97.1 97.5 Basic income per common share $ 4.47 $ 3.99 $ 4.57 Diluted income per common share $ 4.47 $ 3.99 $ 4.52 As of June 29, 2014, we had no remaining options to purchase shares. For the years ended 2014 and 2013 , all outstanding options to purchase shares were included in the computation of diluted common shares outstanding.

Other Expense, Net

Other Expense, Net	12 Months Ended
	Dec. 31, 2015
Other Income and Expenses [Abstract]
Other Expense, Net	Other Expense, Net The components of other income (expense), net, were as follows (dollars in millions): Year Ended December 31 2015 2014 2013 Asset disposals and write-offs $ (14.0 ) $ (10.1 ) $ (13.2 ) Integration-related and other costs (a) (12.9 ) (20.0 ) (17.4 ) DeRidder restructuring (b) 7.1 (7.3 ) — Sale of St. Helens Paper Mill Site (c) 6.7 — — Refundable state tax credit (d) 3.6 — — Class action lawsuit settlement (e) — (17.6 ) — Acquisition-related costs (f) — — (17.2 ) Pension curtailment charges (g) — — (10.9 ) Other 2.8 (2.3 ) (0.3 ) Total $ (6.7 ) $ (57.3 ) $ (59.0 ) ___________ (a) Includes Boise acquisition integration-related and other costs, which primarily relate to severance, retention, travel, and professional fees. (b) 2015 and 2014 include amounts from restructuring activities at our mill in DeRidder, Louisiana including costs related to the conversion of the No. 3 newsprint machine to containerboard, our exit from the newsprint business, and other improvements. We completed the restructuring activities in first quarter 2015. In 2015, we recorded $7.1 million of income from vendor settlements. (c) 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. (d) 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, which was recorded as a benefit. (e) 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. (f) Includes $17.2 million of acquisition-related costs, primarily for professional fees related to transaction-advisory services and expenses related to financing the acquisition of Boise. (g) Includes $10.9 million of non-cash pension curtailment charges related to pension plan changes in which certain hourly corrugated plant and containerboard mill employees will transition from a defined benefit pension plan to a defined contribution (401k) plan.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The following is an analysis of the components of the consolidated income tax provision (dollars in millions): 2015 2014 2013 Current income tax provision (benefit) - U.S. Federal $ 205.1 $ 185.1 $ 129.6 State and local 20.5 33.1 12.7 Foreign 0.4 0.9 0.3 Total current provision for taxes 226.0 219.1 142.6 Deferred - U.S. Federal (3.8 ) (5.0 ) (160.5 ) State and local 5.6 7.6 0.3 Foreign (0.1 ) — (0.1 ) Total deferred provision (benefit) for taxes 1.7 2.6 (160.3 ) Total provision (benefit) for taxes $ 227.7 $ 221.7 $ (17.7 ) The effective tax rate varies from the U.S. Federal statutory tax rate principally due to the following (dollars in millions): 2015 2014 2013 Provision computed at U.S. Federal statutory rate of 35% $ 232.6 $ 215.0 $ 148.3 Alternative fuel mixture and cellulosic biofuel producer credits — — (166.0 ) State and local taxes, net of federal benefit 20.0 20.5 13.6 Domestic manufacturers deduction (19.9 ) (16.5 ) (11.7 ) Other (5.0 ) 2.7 (1.9 ) Total $ 227.7 $ 221.7 $ (17.7 ) Tax benefits in 2013 included $166.0 million for the release of ASC 740 uncertain tax positions related to the taxability of the alternative energy tax credits acquired in the acquisition of Boise and the completion of the IRS audit of PCA's 2008 and 2009 Federal income tax returns including the Filer City mill's cellulosic biofuel tax credits. For further discussion regarding these credits, see Note 7 , Alternative Energy Tax Credits . The following details the scheduled expiration dates of our tax effected net operating loss (NOL) and other tax carryforwards at December 31, 2015 (dollars in millions): 2016 Through 2025 2026 Through 2035 Indefinite Total U.S. federal and non-U.S. NOLs $ — $ 70.9 $ — $ 70.9 State taxing jurisdiction NOLs 1.6 0.7 — 2.3 U.S. federal, non-U.S., and state tax credit carryforwards — 0.1 — 0.1 U.S. federal capital loss carryforwards 5.1 — — 5.1 Total $ 6.7 $ 71.7 $ — $ 78.4 Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts for income tax purposes. Deferred income tax assets and liabilities at December 31 are summarized as follows (dollars in millions): December 31 2015 2014 Deferred tax assets: Accrued liabilities $ 18.3 $ 19.0 Employee benefits and compensation 32.5 44.2 Inventories 3.9 — Net operating loss carryforwards 73.2 85.2 Stock options and restricted stock 10.7 8.9 Pension and postretirement benefits 148.2 139.1 Derivatives 13.7 16.0 Capital loss, general business, foreign, and AMT credit carryforwards 5.2 1.8 Gross deferred tax assets $ 305.7 $ 314.2 Valuation allowance (a) (5.1 ) (1.7 ) Net deferred tax assets $ 300.6 $ 312.5 Deferred tax liabilities: Property, plant, and equipment $ (545.8 ) $ (531.6 ) Goodwill and intangible assets (101.8 ) (107.7 ) Inventories — (7.4 ) Total deferred tax liabilities $ (647.6 ) $ (646.7 ) Net deferred tax liabilities (b) $ (347.0 ) $ (334.2 ) ___________ (a) Deferred tax assets are reduced by a valuation allowance when it is more likely than not that some portion of the deferred tax assets will not be realized. The 2015 valuation allowance relates to capital losses. In 2014, of the $1.7 million valuation allowance, $1.1 million relates to foreign net operating loss carryforwards and credits and $0.6 million relates to capital losses. We do not expect to generate capital gains before the capital losses expire. If or when recognized, the tax benefits relating to the reversal of any of or all of the valuation allowance would be recognized as a benefit to income tax expense. (b) As of December 31, 2015 , we did not recognize U.S. deferred income taxes on our cumulative total of undistributed foreign earnings for our non-U.S. subsidiaries. We indefinitely reinvest our earnings in operations outside the United States. It is not practicable to determine the amount of unrecognized deferred tax liability on these undistributed earnings because the actual tax liability, if any, is dependent on circumstances existing when the repatriation occurs. Cash payments for federal, state, and foreign income taxes were $238.3 million , $189.5 million , and $90.7 million for the years ended December 31, 2015 , 2014 , and 2013 , respectively. The following table summarizes the changes related to PCA’s gross unrecognized tax benefits excluding interest and penalties (dollars in millions): 2015 2014 2013 Balance as of January 1 $ (4.4 ) $ (5.4 ) $ (111.3 ) Increase related to acquisition of Boise Inc. (a) — — (65.2 ) Increases related to prior years’ tax positions (2.8 ) (1.0 ) (0.1 ) Increases related to current year tax positions (0.4 ) (0.3 ) (1.5 ) Decreases related to prior years' tax positions (b) — 0.9 64.8 Settlements with taxing authorities (c) 0.7 0.5 106.2 Expiration of the statute of limitations 1.1 0.9 1.7 Balance at December 31 $ (5.8 ) $ (4.4 ) $ (5.4 ) ___________ (a) In 2013, PCA acquired $65.2 million of gross unrecognized tax benefits from Boise Inc. that related primarily to the taxability of the alternative energy tax credits. (b) The 2013 amount includes a $64.3 million gross decrease related to the taxability of the alternative energy tax credits claimed in 2009 excise tax returns by Boise Inc. For further discussion regarding these credits, see Note 7 , Alternative Energy Tax Credits . (c) The 2013 amount includes a $104.7 million gross decrease related to the conclusion of the Internal Revenue Service audit of PCA’s alternative energy tax credits. For further discussion regarding these credits, see Note 7 , Alternative Energy Tax Credits . At December 31, 2015 , PCA had recorded a $5.8 million gross reserve for unrecognized tax benefits, excluding interest and penalties. Of the total, $4.2 million (net of the federal benefit for state taxes) would impact the effective tax rate if recognized. PCA recognizes interest accrued related to unrecognized tax benefits and penalties as income tax expense. At December 31, 2015 and 2014, we had an insignificant amount of interest and penalties recorded for unrecognized tax benefits included in the table above. PCA does not expect the unrecognized tax benefits to change significantly over the next 12 months. PCA is subject to taxation in the United States and various state and foreign jurisdictions. A federal examination of the tax years 2010 - 2012 was concluded in February 2015. A federal examination of the 2013 tax year began in October 2015. The tax years 2014 - 2015 remain open to federal examination. The tax years 2011 - 2015 remain open to state examinations. Some foreign tax jurisdictions are open to examination for the 2008 tax year forward. Through the Boise acquisition, PCA recorded net operating losses and credit carryforwards from 2008 through 2011 and 2013 that are subject to examinations and adjustments for at least three years following the year in which utilized.

Alternative Energy Tax Credits

Alternative Energy Tax Credits	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Alternative Energy Tax Credits	Alternative Energy Tax Credits The Company generates black liquor as a by-product of its pulp manufacturing process, which entitled it to certain federal income tax credits. When black liquor is mixed with diesel, it is considered an alternative fuel that was eligible for a $0.50 per gallon refundable alternative energy tax credit for gallons produced before December 31, 2009. Black liquor was also eligible for a $1.01 per gallon taxable cellulosic biofuel producer credit for gallons of black liquor produced and used in 2009. In 2013, we reversed $166.0 million of a reserve for unrecognized tax benefits for alternative energy tax credits as a benefit to income taxes. Approximately $103.9 million ( $102.0 million of tax, net of the federal benefit for state taxes, plus $1.9 million of accrued interest) of the reversal is due to the completion of the IRS audit and receipt of a confirmation letter from the Joint Committee on Taxation that their review of the Filer City claimed credits was complete. This reserve was established in 2010 as an unrecognized tax benefit under ASC 740, “Income Taxes,” because the IRS guidelines did not specifically address the unique and proprietary nature of the Filer City mill process for which we had claimed cellulosic biofuel credits. The remaining $62.1 million (net of federal benefit for state taxes) of the reversal was acquired from Boise for the 2009 alternative energy tax credits that Boise had claimed through excise tax refunds. In November 2013, an IRS Chief Counsel Memorandum was published that provided guidance concerning the taxability of the alternative energy tax credits. Based on this new fact, the reserve acquired from Boise was also reversed as a benefit to income taxes.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill Goodwill represents the excess of the cost of an acquired business over the fair value of the identifiable tangible and intangible assets acquired and liabilities assumed in a business combination. At December 31, 2015 and 2014 , we had $488.8 million and $491.6 million , respectively, of goodwill recorded in our Packaging segment and $55.2 million for both years in our Paper segment on our Consolidated Balance Sheets. Changes in the carrying amount of our goodwill were as follows (dollars in millions): Packaging Paper Goodwill Balance at January 1, 2014 $ 472.9 $ 53.9 $ 526.8 Acquisitions (a) 12.2 — 12.2 Adjustments related to purchase accounting (b) 6.5 1.3 7.8 Balance at December 31, 2014 491.6 55.2 546.8 Sale of Hexacomb Europe and Mexico (c) (2.8 ) — (2.8 ) Balance at December 31, 2015 $ 488.8 $ 55.2 $ 544.0 ___________ (a) In April 2014, we acquired the assets of Crockett Packaging, a corrugated products manufacturer, for $21.2 million , before $0.7 million of working capital adjustments, and recorded $12.2 million of goodwill in our Packaging segment. (b) Adjustments relate primarily to the Boise acquisition, see Note 3 , Acquisitions and Dispositions , for more information. (c) During 2015, we sold the assets of Hexacomb Europe and Mexico, a corrugated products manufacturer, for $23.0 million and reduced goodwill in our Packaging segment by $2.8 million . Intangible Assets Intangible assets are comprised of customer relationships and trademarks and trade names. The weighted average useful life, gross carrying amount, and accumulated amortization of our intangible assets were as follows (dollars in millions): As of December 31, 2015 As of December 31, 2014 Weighted Average Remaining Useful Life (in Years) Gross Accumulated Weighted Average Remaining Useful Life (in Years) Gross Accumulated Customer relationships 13.3 $ 311.5 $ 57.3 14.3 $ 311.5 $ 36.9 Trademarks and trade names 12.5 21.8 5.2 13.4 21.8 3.0 Other 1.2 0.2 0.2 2.2 0.2 0.1 Total intangible assets (excluding goodwill) 13.3 $ 333.5 $ 62.7 14.2 $ 333.5 $ 40.0 Amortization expense was $22.7 million , $22.6 million , and $6.4 million for the years ended December 31, 2015 , 2014 , and 2013 , respectively. Estimated amortization expense of intangible assets over the next five years is expected to approximate $22.5 million ( 2016 ), $22.4 million ( 2017 ), $22.2 million ( 2018 ), $21.3 million ( 2019 ), and $21.3 million ( 2020 ). Impairment Testing We test goodwill for impairment annually in the fourth quarter or sooner if events or changes in circumstances indicate that the carrying value of the asset may exceed fair value. Additionally, when we experience changes to our business or operating environment, we evaluate the remaining useful lives of our finite-lived purchased intangible assets to determine whether any adjustments to the useful lives are necessary. We completed our test in the fourth quarter and there was no indication of goodwill or intangible asset impairment.

Accrued Liabilities

Accrued Liabilities	12 Months Ended
	Dec. 31, 2015
Accrued Liabilities, Current [Abstract]
Accrued Liabilities	Accrued Liabilities The components of accrued liabilities were as follows (dollars in millions): December 31, 2015 2014 Compensation and benefits $ 106.4 $ 130.8 Medical insurance and workers’ compensation 31.1 27.0 Franchise, property, sales and use taxes 16.0 17.5 Customer volume discounts and rebates 15.3 13.9 Severance, retention, and relocation 7.3 8.3 Environmental liabilities and asset retirement obligations 7.9 7.1 Other 9.5 15.4 Total $ 193.5 $ 220.0

Debt

Debt	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Debt	Debt At December 31, 2015 and 2014 , our long-term debt and interest rates on that debt were as follows (dollars in millions): December 31, 2015 December 31, 2014 Amount Interest Rate Amount Interest Rate Revolving Credit Facility, due October 2018 $ — — % $ — — % Five-Year Term Loan, due October 2018 25.0 1.80 65.0 1.54 Seven-Year Term Loan, due October 2020 637.0 2.05 643.5 1.79 6.50% Senior Notes due March 2018 150.0 6.50 150.0 6.50 3.90% Senior Notes, net of discounts of $0.3 million as of both December 31, 2015 and 2014, respectively, due June 2022 399.7 3.90 399.7 3.90 4.50% Senior Notes, net of discount of $1.5 million and $1.7 million as of December 31, 2015 and 2014, respectively, due November 2023 698.5 4.50 698.3 4.50 3.65% Senior Notes, net of discount of $1.0 million and $1.1 million as of December 31, 2015 and 2014, due September 2024 399.0 3.65 398.9 3.65 Total 2,309.2 3.67 2,355.4 3.56 Less current portion 6.5 2.05 6.5 1.79 Total long-term debt $ 2,302.7 3.67 % $ 2,348.9 3.56 % As of December 31, 2015 , the details of our borrowings were as follows: • Senior Unsecured Credit Agreement . On October 18, 2013, we entered into a $1.65 billion senior unsecured credit facility. Loans bear interest at LIBOR plus a margin that is determined based upon our credit ratings. The financing consisted of: ◦ Revolving Credit Facility : A $350.0 million unsecured revolving credit facility with variable interest (LIBOR plus a margin) due October 2018. During 2015 , we did not borrow under the Revolving Credit Facility. At December 31, 2015 , we had $23.5 million of outstanding letters of credit that were considered outstanding on the revolving credit facility, resulting in $326.5 million of unused borrowing capacity. The outstanding letters of credit were primarily for workers compensation. We are required to pay commitment fees on the unused portions of the credit facility. ◦ Five-Year Term Loan : A $650.0 million unsecured term loan with variable interest (LIBOR plus 1.375% ), payable quarterly, due October 2018. The balance outstanding at December 31, 2015 was $25.0 million . ◦ Seven-Year Term Loan : A $650.0 million unsecured term loan with variable interest (LIBOR plus 1.625% ), payable quarterly, due October 2020. The balance outstanding at December 31, 2015 was $637.0 million . • 6.50% Senior Notes. On March 25, 2008, we issued $150.0 million of 6.50% senior notes due March 15, 2018, through a registered public offering. • 3.90% Senior Notes. On June 26, 2012, we issued $400.0 million of 3.90% senior notes due June 15, 2022, through a registered public offering. • 4.50% Senior Notes . On October 22, 2013, we issued $700.0 million of 4.50% senior notes due November 1, 2023, through a registered public offering. • 3.65% Senior Notes. On September 5, 2014, we issued $400.0 million of 3.65% fixed-rate senior notes due September 15, 2024, through a registered public offering. In connection with the $400.0 million debt issuance, we paid $3.4 million of deferred financing costs, which we are amortizing to interest expense using the effective interest method over the term of the debt. The instruments governing our indebtedness contain financial and other covenants that limit the ability of PCA and its subsidiaries to enter into sale and leaseback transactions, incur liens, incur indebtedness at the subsidiary level, enter into certain transactions with affiliates, merge or consolidate with any other person or sell or otherwise dispose of all or substantially all of our assets. Our credit facility also requires us to comply with certain financial covenants, including maintaining a minimum interest coverage ratio and a maximum leverage ratio. A failure to comply with these restrictions could lead to an event of default, which could result in an acceleration of any outstanding indebtedness and/or prohibit us from drawing on the revolving credit facility. Such an acceleration may also constitute an event of default under the senior notes indenture. At December 31, 2015 , we were in compliance with these covenants. At December 31, 2015 , we have $1,647.2 million of fixed-rate senior notes and $662.0 million of variable-rate term loans outstanding. At December 31, 2015 , the fair value of our fixed-rate debt was estimated to be $1,698.2 million . The difference between the book value and fair value is due to the difference between the period-end market interest rate and the stated rate of our fixed-rate debt. We estimated the fair value of our fixed-rate debt using quoted market prices (Level 2 inputs), discussed further in Note 2 , Summary of Significant Accounting Policies . The fair value of our variable-rate term debt approximates the carrying amount as our cost of borrowing is variable and approximates current market rates. Repayments, Interest, and Other In 2015, we used cash on hand to repay $40.0 million of debt outstanding under the Five-Year Term Loan and $6.5 million under the Seven-Year Term Loan. In 2014, we used the proceeds of our $400.0 million of 3.65% fixed-rate senior notes offering and other cash on hand to repay $591.5 million of debt outstanding under the Five-Year and Seven-Year Term Loans. On December 23, 2013, we repaid in full the $109.0 million that was outstanding under, and terminated, the receivables credit facility that was scheduled to terminate in October 2014. In October 2013, we used debt and cash on hand to finance the acquisition of Boise, repay $953.6 million of indebtedness, which included $829.8 million of acquired Boise debt, and for general corporate purposes. As of December 31, 2015 , annual principal maturities for debt, excluding unamortized debt discount, are: $6.5 million each year for 2016 and 2017 ; $181.5 million for 2018 ; $6.5 million for 2019 ; $611.0 million for 2020 ; and $1.5 billion for 2020 and thereafter. At both December 31, 2015 and 2014 , the reference interest rate (LIBOR) of our variable rate debt for both our Five-Year Term Loan, due October 2018, and Seven-Year Term Loan, due October 2020, was 0.42% . The applicable margin of our variable rate debt at both December 31, 2015 and 2014 , for our Five-Year Term Loan, due October 2018, and Seven-Year Term Loan, due October 2020, was 1.375% and 1.625% , respectively. Interest payments and redemption premium payments paid in connection with the Company’s debt obligations for the years ended December 31, 2015 , 2014 , and 2013 , were $85.5 million , $77.0 million , and $105.7 million (including a $54.8 million redemption premium in 2013 related to the acquired Boise Inc. debt), respectively. Included in interest expense, net, are amortization of financing costs and amortization of treasury lock settlements. Amortization of treasury lock settlements was a $5.7 million net loss in 2015, 2014, and 2013. Amortization of financing costs in 2015, 2014, and 2013 was $1.8 million , $3.3 million (including a $1.5 million write-off of deferred financing costs related to the September 2014 debt refinancing), and $10.3 million (including $8.2 million for acquisition-related financing fees), respectively.

Employee Benefit Plans and Othe

Employee Benefit Plans and Other Postretirement Plans	12 Months Ended
	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans and Other Postretirement Plans	Employee Benefit Plans and Other Postretirement Benefits PCA has defined pension benefit plans for both salaried and hourly employees. The plans covering salaried employees are closed to new entrants with only certain current active participants still accruing benefits. The plans covering certain hourly employees are closed to new participants. We also have a Supplemental Executive Retirement Plan (SERP) and other nonqualified defined benefit pension plans that provide unfunded supplemental retirement benefits to certain of our executives and former executives. The SERP provides for incremental pension benefits in excess of those offered in our principal pension plans. Other Postretirement Benefits PCA provides postretirement medical benefits for certain salaried employees and postretirement medical and life insurance benefits for certain hourly employees. For salaried employees, the plan covers employees retiring from PCA on or after attaining age 58 who have had at least 10 years of full-time service with PCA after attaining age 48 . For hourly employees, the postretirement medical and life insurance coverage, where applicable, is available according to the eligibility provisions contained in the applicable collective bargaining agreement in effect at the employee’s work location. Obligations and Funded Status of Defined Benefit Pension and Other Postretirement Benefits Plans The funded status of PCA's plans change from year to year based on the plan asset investment return, contributions, benefit payments, the discount rate used to measure the liability, and expected participant longevity. The following table, which includes only company-sponsored defined benefit and other postretirement benefit plans, reconciles the beginning and ending balances of the projected benefit obligation and the fair value of plan assets. We recognize the unfunded status of these plans on the Consolidated Balance Sheets, and we recognize changes in funded status in the year changes occur through the Consolidated Statements of Comprehensive Income (dollars in millions): Pension Plans Postretirement Plans Year Ended December 31 Year Ended December 31 2015 2014 2015 2014 Change in Benefit Obligation Benefit obligation at beginning of period $ 1,129.6 $ 929.8 $ 31.9 $ 26.3 Service cost 24.0 22.7 1.7 1.6 Interest cost 46.2 45.9 1.2 1.2 Plan amendments 3.0 2.6 — — Actuarial (gain) loss (a) (75.7 ) 159.2 (11.4 ) 4.1 Special termination benefits — 0.3 — — Participant contributions — — 1.2 1.2 Benefits paid (34.6 ) (30.9 ) (3.2 ) (2.5 ) Benefit obligation at plan year end $ 1,092.5 $ 1,129.6 $ 21.4 $ 31.9 Accumulated benefit obligation portion of above $ 1,048.5 $ 1,078.6 Change in Fair Value of Plan Assets Plan assets at fair value at beginning of period $ 805.9 $ 772.1 $ — $ — Actual return on plan assets (8.1 ) 63.4 — — Company contributions 1.2 1.3 2.0 1.3 Participant contributions — — 1.2 1.2 Benefits paid (34.6 ) (30.9 ) (3.2 ) (2.5 ) Fair value of plan assets at plan year end $ 764.4 $ 805.9 $ — $ — Underfunded status $ (328.1 ) $ (323.7 ) $ (21.4 ) $ (31.9 ) Amounts Recognized on Consolidated Balance Sheets Current liabilities $ (0.9 ) $ (1.1 ) $ (1.1 ) $ (1.4 ) Noncurrent liabilities (327.2 ) (322.6 ) (20.3 ) (30.5 ) Accrued obligation recognized at December 31 $ (328.1 ) $ (323.7 ) $ (21.4 ) $ (31.9 ) Amounts Recognized in Accumulated Other Comprehensive (Income) Loss (Pre-Tax) Prior service cost $ 25.1 $ 27.6 $ 0.2 $ 0.3 Actuarial loss 149.4 172.6 (6.0 ) 5.5 Total $ 174.5 $ 200.2 $ (5.8 ) $ 5.8 ___________ (a) In 2015, the increase in the weighted average discount rate used to estimate our pension benefit obligations and changes in mortality assumptions from the Society of Actuaries resulted in an actuarial gain. The actuarial loss in 2014 was due primarily to a decrease in the weighted average discount rate and updated mortality assumptions. Components of Net Periodic Benefit Cost and Other Comprehensive (Income) Loss The components of net periodic benefit cost and other comprehensive (income) loss (pretax) were as follows (dollars in millions): Pension Plans Postretirement Plans Year Ended December 31 Year Ended December 31 2015 2014 2013 2015 2014 2013 Service cost $ 24.0 $ 22.7 $ 24.5 $ 1.7 $ 1.6 $ 2.1 Interest cost 46.2 45.9 21.5 1.2 1.2 1.3 Expected return on plan assets (53.1 ) (50.7 ) (21.4 ) — — — Special termination benefits — 0.3 — — — — Net amortization of unrecognized amounts Prior service cost 5.5 6.5 6.2 0.1 (0.2 ) (0.4 ) Actuarial loss 8.7 0.6 4.7 0.1 0.1 0.5 Curtailment loss (a) — — 10.9 — — — Net periodic benefit cost $ 31.3 $ 25.3 $ 46.4 $ 3.1 $ 2.7 $ 3.5 Changes in plan assets and benefit obligations recognized in other comprehensive (income) loss Actuarial net (gain) loss $ (14.5 ) $ 146.4 $ (58.7 ) $ (11.4 ) $ 4.2 $ (7.8 ) Prior service cost 3.0 2.6 13.8 — — — Amortization of prior service cost (5.5 ) (6.5 ) (6.2 ) (0.1 ) 0.2 0.4 Amortization of actuarial loss (8.7 ) (0.6 ) (4.7 ) (0.1 ) (0.1 ) (0.5 ) Curtailment loss (a) — — (10.9 ) — — — Total recognized in other comprehensive (income) loss (b) (25.7 ) 141.9 (66.7 ) (11.6 ) 4.3 (7.9 ) Total recognized in net periodic benefit cost and other comprehensive (income) loss - pretax $ 5.6 $ 167.2 $ (20.3 ) $ (8.5 ) $ 7.0 $ (4.4 ) ___________ (a) In 2013, we recognized curtailment losses in "Other expense, net" in the Consolidated Statements of Income for recent USW negotiations, resulting in the bifurcation of the active USW population between those grandfathered in the current formula (with continued accruals) and non-grandfathered in the current formula (frozen benefits at the contract date). (b) Accumulated losses in excess of 10% of the greater of the projected benefit obligation or the market-related value of assets will be recognized on a straight-line basis over the average remaining service period of active employees, which is between seven to ten years, to the extent that losses are not offset by gains in subsequent years. The estimated net loss and prior service cost that will be amortized from "Accumulated other comprehensive loss" into pension expense in 2016 is $10.5 million . The accumulated benefit obligations for the plans with obligations in excess of plan assets, is $1.05 billion . Assumptions The following table presents the assumptions used in the measurement of our benefits obligations: Pension Plans Postretirement Plans December 31 December 31 2015 2014 2013 2015 2014 2013 Weighted-Average Assumptions Used to Determine Benefit Obligations at December 31 Discount rate 4.51% 4.14% 5.00% 4.35% 3.95% 4.85% Rate of compensation increase 4.00% 4.00% 4.00% N/A N/A N/A Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost for the Years Ended December 31 Discount rate 4.14% 5.00% 4.57% 3.95% 4.85% 4.00% Expected return on plan assets 6.73% 6.69% 6.53% N/A N/A N/A Rate of compensation increase 4.00% 4.00% 4.00% N/A N/A N/A Discount Rate Assumption. The discount rate reflects the current rate at which the pension obligations could be settled on the measurement date: December 31. The discount rate assumption used to calculate the present value of pension and postretirement benefit obligations reflects the rates available on high-quality, fixed-income debt instruments on December 31. In all periods, the bonds included in the models reflect anticipated investments that would be made to match the expected monthly benefit payments over time. The plans' projected cash flows were duration-matched to these models to develop an appropriate discount rate. Beginning in 2016, we refined the method used to determine the service and interest cost components of our net periodic benefit cost. Previously, the cost was determined using a single weighted-average discount rate derived from the yield curve. Under the refined method, known as the spot rate approach, we will use individual spot rates along the yield curve that correspond with the timing of each benefit payment. We believe this change provides a more precise measurement of service and interest costs by improving the correlation between projected cash outflows and corresponding spot rates on the yield curve. Compared to the previous method, the spot rate approach will decrease the service and interest components of our benefit costs about $8 million in 2016. There is no impact on the total benefit obligation. We will account for this change prospectively as a change in accounting estimate. Asset Return Assumption. The expected return on plan assets reflects the expected long-term rates of return for the categories of investments currently held in the plans as well as anticipated returns for additional contributions made in the future. The expected long-term rate of return is adjusted when there are fundamental changes in expected returns on the plan investments. The weighted-average expected return on plan assets we will use in our calculation of 2016 net periodic pension benefit cost is 6.57% . Rate of Compensation Increase. The rate of compensation increase is determined by PCA based upon annual reviews. The compensation increase assumption is not applicable for all plans as many of our pension plans are frozen and not accruing benefits. Health Care Cost Trend Rate Assumptions. PCA assumed health care cost trend rates for its postretirement benefits plans were as follows: 2015 2014 2013 Health care cost trend rate assumed for next year 7.60% 7.75% 7.75% Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) 4.50% 5.00% 5.00% Year that the rate reaches the ultimate trend rate 2024 2023 2020 Postretirement Health Care Plan Assumptions. For postretirement health care plan accounting, PCA reviews external data and its own historical trends for health care costs to determine the health care cost trend rate assumption. A one-percentage point change in assumed health care cost trend rates would have the following effects on the 2015 postretirement benefit obligation and the 2015 net post retirement benefit cost (dollars in millions): 1-Percentage Point Increase 1-Percentage Point Decrease Effect on postretirement benefit obligation $ 0.8 $ (0.7 ) Effect on net postretirement benefit cost — (0.1 ) Investment Policies and Strategies PCA has retained the services of professional advisors to oversee pension investments and provide recommendations regarding investment strategy. PCA’s overall strategy and related apportionments between equity and debt securities may change from time to time based on market conditions, external economic factors, and the funded status of the plans. The general investment objective for all of our plan assets is to optimize growth of the pension plan trust assets, while minimizing the risk of significant losses to enable the plans to satisfy their benefit payment obligations over time. The objectives take into account the long-term nature of the benefit obligations, the liquidity needs of the plans, and the expected risk/return trade-offs of the asset classes in which the plans may choose to invest. Assets of our pension plans were invested in the following classes of securities at December 31, 2015 and 2014 : Percentage of Fair Value 2015 2014 Fixed income securities 55 % 54 % International equity securities 22 23 Domestic equity securities 20 20 Real estate securities 1 1 Other 2 2 At December 31, 2015 , the targeted investment allocations differed between the acquired Boise plans and PCA's historical plans based on funded status. At December 31, 2015 , PCA's historical plans, which comprised $275.2 million of the fair value of plan assets, targeted 39% invested in equities, 58% invested in bonds, and 3% in other, whereas the Boise plans, which comprised $489.2 million of the total fair value of plan assets, targeted 45% in equities and 55% in bonds. Our retirement committee reviews the investment allocations for reasonableness at a minimum, semi-annually. Investment securities, in general, are exposed to various risks, such as interest rate, credit, and overall market volatility risk, all of which are subject to change. Due to the level of risk associated with some investment securities, it is reasonably possible that changes in the values of investment securities will occur in the near term, and such changes could materially affect the reported amounts. Fair Value Measurements of Plan Assets The following tables set forth, by level within the fair value hierarchy, discussed in Note 2 , Summary of Significant Accounting Policies , the pension plan assets, by major asset category, at fair value at December 31, 2015 and 2014 (dollars in millions): Fair Value Measurements at December 31, 2015 Asset Category Quoted Prices in Active Markets for Identical Significant Other Observable Significant Total Short-term investments (a) $ — $ 4.1 $ — $ 4.1 Mutual funds (b): Domestic equities 47.1 — — 47.1 International equities 50.7 — — 50.7 Real estate 8.5 — — 8.5 Fixed income 156.5 — — 156.5 Common/collective trust funds (a): Domestic equities — 104.4 — 104.4 International equities — 121.6 — 121.6 Fixed income — 263.0 — 263.0 Private equity securities (c) — — 6.4 6.4 Total securities at fair value $ 262.8 $ 493.1 $ 6.4 $ 762.3 Receivables and accrued expenses 2.1 Total fair value of plan assets $ 764.4 Fair Value Measurements at December 31, 2014 Asset Category Quoted Prices in Active Markets for Identical Significant Other Observable Significant Total Short-term investments (a) $ — $ 1.8 $ — $ 1.8 Mutual funds (b): Domestic equities 38.2 — — 38.2 International equities 49.9 — — 49.9 Real estate 8.9 — — 8.9 Fixed income 178.2 — — 178.2 Common/collective trust funds (a): Domestic equities — 122.3 — 122.3 International equities — 137.8 — 137.8 Fixed income — 259.3 — 259.3 Private equity securities (c) — — 8.1 8.1 Total securities at fair value $ 275.2 $ 521.2 $ 8.1 $ 804.5 Receivables and accrued expenses 1.4 Total fair value of plan assets $ 805.9 ____________ (a) Investments in common/collective trust funds valued using net asset values (NAV) provided by the administrator of the funds. We use NAV as a practical expedient to fair value. The NAV is based on the value of the underlying assets owned by the fund, minus its liabilities, and then divided by the number of units outstanding. While the underlying assets are actively traded on an exchange, the funds are not. There are currently no redemption restrictions on these investments. There are certain funds with one-day redeemable notice. (b) Investments in mutual funds valued at quoted market values on the last business day of the fiscal year. (c) Investments in this category are invested in the Pantheon Global Secondary Fund IV, LP. The fund specializes in investments in the private equity secondary market and occasionally directly in private companies to maximize capital growth. Fund investments are carried at fair value as determined quarterly using the market approach to estimate the fair value of private investments. The market approach utilizes prices and other relevant information generated by market transactions, type of security, size of the position, degree of liquidity, restrictions on the disposition, latest round of financing data, current financial position, and operating results, among other factors. In circumstances where fair values are not provided with respect to any of the company's fund investments, the investment advisor will seek to determine the fair value of such investments based on information provided by the general partners or managers of such funds or from other sources. Audited financial statements are provided by fund management annually. Notwithstanding the above, the variety of valuation bases adopted and quality of management data of the ultimate underlying investee companies means that there are inherent difficulties in determining the value of the investments. Amounts realized on the sale of these investments may differ from the calculated values. Boise had originally committed to a $15.0 million investment, with $5.0 million of the commitment unfunded at December 31, 2015 . The following table sets forth a summary of changes in the fair value of the pension plans' Level 3 assets for the year ended December 31, 2015 (dollars in millions): 2015 Balance, beginning of year $ 8.1 Sales (1.8 ) Unrealized gain 0.1 Balance, end of year $ 6.4 Funding and Cash Flows PCA makes pension plan contributions that are sufficient to fund its actuarially determined costs, generally equal to the minimum amounts required by the Employee Retirement Income Security Act (ERISA). From time to time, PCA may make discretionary contributions based on the funded status of the plans, tax deductibility, income from operations, and other factors. In 2015 , we did not make any contributions to our qualified pension plans. We made contributions of $0.4 million and $30.0 million to our qualified pension plans in 2014 and 2013, respectively. We expect to contribute at least the estimated required minimum contributions to our qualified pension plans of approximately $27 million in 2016. The following are estimated benefit payments to be paid to current plan participants by year (dollars in millions). Qualified pension benefit payments are paid from plan assets, while nonqualified pension benefit payments are paid by the Company. Pension Plans Postretirement Plans 2016 $ 37.8 $ 1.1 2017 40.9 1.1 2018 44.8 1.3 2019 48.6 1.3 2020 52.4 1.5 2021 - 2025 312.7 7.9 Defined Contribution Plans Some of our employees participate in contributory defined contribution savings plans, available to most of our salaried and hourly employees. The defined contribution plans permit participants to make contributions by salary reduction pursuant to Section 401(k) of the Code. PCA made employer-matching contributions of $37.9 million , $28.3 million , and $15.0 million in 2015 , 2014 , and 2013 , respectively. Company matching contributions to certain full-time salaried employees were made in company stock, through our Employee Stock Ownership Plan (ESOP). All other matching contributions were in cash. Beginning in 2016, all company matching contributions to all employees will be made in cash. We expense employer matching contributions and charge dividends on shares held by the ESOP to retained earnings. Shares of company stock held by the ESOP are included in basic shares for earnings-per-share computations. At December 31, 2015 and 2014 , the ESOP held 3.1 million and 2.2 million shares of company stock, respectively. Certain salaried and hourly employees that are not participating in a PCA sponsored defined benefit pension plan receive a service-related company retirement contribution to their defined contribution plan account in addition to any employer matching contribution. This contribution increases with years of service and ranges from 3% to 5% of base pay. We contributed $12.4 million , $7.4 million , and $5.3 million for this retirement contribution during the years ended December 31, 2015 , 2014 , and 2013 , respectively. Deferred Compensation Plans Key managers can elect to participate in a deferred compensation plan. The deferred compensation plan is unfunded; therefore, benefits are paid from our general assets. At December 31, 2015 and 2014 , we had $12.8 million and $12.4 million , respectively, of liabilities attributable to participation in our deferred compensation plan on our Consolidated Balance Sheets.

Asset Retirement Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2015
Asset Retirement Obligation [Abstract]
Asset Retirement Obligations	Asset Retirement Obligations Our asset retirement obligations relate predominantly to landfill closure, wastewater treatment pond dredging, closed-site monitoring costs, and certain leasehold improvements. In accordance with ASC 410, "Asset Retirement and Environmental Obligations , " we recognize the fair value of these liabilities as an asset retirement obligation and capitalize that cost as part of the cost basis of the related asset in the period in which the costs are incurred if sufficient information is available to reasonably estimate the fair value of the obligation. Fair value estimates are determined using Level 3 inputs in the fair value hierarchy. The fair value of our asset retirement obligations is measured using expected future cash outflows discounted using the company's credit-adjusted risk-free interest rate. Over time, the liability is accreted to its settlement value, and the capitalized cost is depreciated over the useful life of the related asset. These liabilities are based on the best estimate of costs and are updated periodically to reflect current technology, laws and regulations, inflation, and other economic factors. Occasionally, we become aware of events or circumstances that require us to revise our future estimated cash flows. When revisions become necessary, we recalculate our obligation and adjust our asset and liability accounts utilizing appropriate discount rates. No assets are legally restricted for purposes of settling asset retirement obligations. Upon settlement of the liability, we will recognize a gain or loss for any difference between the settlement amount and the liability recorded. The following table describes changes to the asset retirement obligation liability (dollars in millions): Year Ended December 31 2015 2014 Asset retirement obligation at beginning of period $ 37.0 $ 32.0 Sale of St. Helens (a) (11.2 ) — Accretion expense 2.1 1.0 Payments (1.6 ) (0.1 ) Revisions in estimated cash flows 0.2 — Liabilities incurred (0.3 ) — Acquisition — 4.1 Asset retirement obligation at end of period $ 26.2 $ 37.0 _______ (a) 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. In connection with the sale, we eliminated $11.2 million of asset retirement obligations that were assumed by the buyer. We have additional asset retirement obligations with indeterminate settlement dates. The fair value of these asset retirement obligations cannot be estimated due to the lack of sufficient information to estimate the settlement dates of the obligations. These asset retirement obligations include, for example, (i) removal and disposal of potentially hazardous materials related to equipment and/or an operating facility if the equipment and/or facilities were to undergo major maintenance, renovation, or demolition and (ii) storage sites or owned facilities for which removal and/or disposal of chemicals and other related materials are required if the operating facility is closed. We will recognize a liability in the period in which sufficient information becomes available to reasonably estimate the fair value of these obligations.

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2015
Share-based Compensation [Abstract]
Share-Based Compensation	Share-Based Compensation The Company has a long-term equity incentive plan, which allows for grants of stock options, stock appreciation rights, restricted stock, and performance awards to directors, officers, and employees, as well as others who engage in services for PCA. The plan, as amended, terminates May 1, 2023 , and authorizes 10.6 million shares of common stock for grant over the life of the plan. As of December 31, 2015 , 1.6 million shares remained available for future issuance under the plan. Forfeitures are added back to the pool of shares of common stock available to be granted at a future date. Restricted Stock Restricted stock awards granted to officers and employees generally vest at the end of a four-year period, and restricted stock awards granted to directors vest immediately. The fair value of restricted stock is determined based on the closing price of the Company’s stock on the grant date. A summary of the Company’s restricted stock activity follows: 2015 2014 2013 Shares Weighted Average Grant- Date Fair Value Shares Weighted Average Grant- Date Fair Value Shares Weighted Average Grant- Date Fair Value Restricted stock at January 1 1,184,299 $ 41.71 1,463,694 $ 31.48 1,771,664 $ 23.44 Granted 218,957 65.16 229,489 70.24 331,053 51.99 Vested (a) (389,481 ) 32.77 (507,222 ) 26.29 (605,458 ) 19.54 Forfeitures (5,981 ) 66.42 (1,662 ) 61.05 (33,565 ) 24.76 Restricted stock at December 31 1,007,794 $ 49.47 1,184,299 $ 41.71 1,463,694 $ 31.48 ___________ (a) The total fair value of awards upon vesting for the years ended December 31, 2015 , 2014 , and 2013 was $26.3 million , $36.4 million , and $29.5 million , respectively . Performance Units Performance award units granted to certain key employees vest four years after the grant date based on the achievement of defined performance rankings compared to a peer group. The performance units are paid out entirely in shares of the Company’s common stock. The awards are valued at the closing price of the Company’s stock on the grant date and expensed over the requisite service period based on the most probable number of awards expected to vest. 2015 2014 2013 Units Weighted Average Grant- Date Fair Value Units Weighted Average Grant- Date Fair Value Units Weighted Average Grant-Date Fair Value Performance units at January 1 127,489 $ 58.25 70,600 $ 47.83 — $ — Granted 53,102 65.04 56,889 71.19 70,600 47.83 Vested (a) (4,916 ) 71.19 — — — — Forfeitures — — — — — — Performance units at December 31 175,675 $ 59.94 127,489 $ 58.25 70,600 $ 47.83 ___________ (a) The total fair value of awards upon vesting for the year ended December 31, 2015 was $0.3 million . Upon vesting of the awards, PCA issued 5,090 shares of its common stock, which included 174 shares for dividends accrued during the vesting period. Compensation Expense Our share-based compensation expense is recorded in "Selling, general, and administrative expenses." Compensation expense for share-based awards recognized in the Consolidated Statements of Income, net of forfeitures was as follows (dollars in millions): Year Ended December 31 2015 2014 2013 Restricted stock $ 15.2 $ 13.8 $ 14.3 Performance units 3.0 1.8 0.5 Impact on income before income taxes 18.2 15.6 14.8 Income tax benefit (7.1 ) (6.1 ) (5.8 ) Impact on net income $ 11.1 $ 9.5 $ 9.0 The fair value of restricted stock and performance units is determined based on the closing price of the Company’s common stock on the grant date. As PCA’s Board of Directors has the ability to accelerate vesting of share-based awards upon an employee’s retirement, the Company accelerates the recognition of compensation expense for certain employees approaching normal retirement age. The unrecognized compensation expense for all share-based awards was as follows (dollars in millions): December 31, 2015 Unrecognized Compensation Expense Remaining Weighted Average Recognition Period (in years) Restricted stock $ 26.6 2.5 Performance units 6.2 2.8 Total unrecognized share-based compensation expense $ 32.8 2.6 We evaluate share-based compensation expense on a quarterly basis based on our estimate of expected forfeitures, review of recent forfeiture activity, and expected future turnover. We recognize the effect of adjusting the forfeiture rate for all expense amortization in the period that we change the forfeiture estimate. The effect of forfeiture adjustments was insignificant in all periods presented.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	12 Months Ended
	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities Hedging Strategy When appropriate, we use derivatives as a risk management tool to mitigate the potential impact of certain market risks. The primary risks managed by using derivative financial instruments are interest rate and foreign currency exchange rate risks. We do not enter into derivative financial instruments for trading or speculative purposes. Interest Rate Risk The Company has used treasury lock derivative instruments to manage interest costs and the risk associated with changing interest rates. In connection with contemplated issuances of ten-year debt securities, PCA entered into interest rate protection agreements with counterparties in 2008, 2010, and 2011 to protect against increases in the ten-year U.S. Treasury Note rate. These treasury rates served as references in determining the interest rates applicable to the debt securities the Company issued in March 2008, February 2011, and June 2012. As a result of changes in the interest rates on those treasury securities between the time PCA entered into the derivative agreements and the time PCA priced and issued the debt securities, the Company: (1) made a payment of $4.4 million to the counterparty upon settlement of the 2008 interest rate protection agreement on March 25, 2008; (2) received a payment of $9.9 million from the counterparties upon settlement of the 2010 interest rate protection agreements on February 4, 2011; and (3) made a payment of $65.5 million to the counterparty upon settlement of the 2011 interest rate protection agreement on June 26, 2012. The Company recorded the effective portion of the settlements in AOCI, and these amounts are being amortized over the terms of the respective notes. Derivative Instruments The impact of derivative instruments on the consolidated statements of income and accumulated OCI was as follows (dollars in millions): Net 2015 2014 Treasury locks, net of tax $ (21.2 ) $ (24.7 ) Gain (Loss) Reclassified Location 2015 2014 2013 Amortization of treasury locks (included in interest expense, net) $ (5.7 ) $ (5.7 ) $ (5.7 ) The net amount of settlement gains or losses on derivative instruments included in accumulated OCI to be amortized over the next 12 months is a net loss of $5.7 million ( $3.5 million after-tax).

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity Dividends During the year ended December 31, 2015 , we paid $200.8 million of dividends to shareholders. On December 15, 2015, PCA's Board of Directors approved a regular quarterly cash dividend of $0.55 per share, which was paid on January 15, 2016, to shareholders of record as of December 28, 2015. The dividend payment was $53.1 million . On February 26, 2015, PCA announced an increase of its quarterly cash dividend on its common stock from an annual payout of $1.60 per share to an annual payout of $2.20 per share. The first quarterly dividend of $0.55 per share was paid on April 15, 2015 to shareholders of record as of March 13, 2015. Share Repurchase Program On July 21, 2015, PCA announced that its Board of Directors authorized the repurchase of an additional $150 million of the company’s outstanding common stock. Together with remaining authority under previously announced programs, at the time of the announcement, the company was authorized to repurchase approximately $205 million of additional shares. Repurchases may be made from time to time in open market or privately negotiated transactions in accordance with applicable securities regulations. The timing and amount of repurchases will be determined by the company in its discretion based on factors such as PCA’s stock price and market and business conditions. Share repurchase activity follows (in millions, except share and per share amounts). Shares Weighted Average Price Per Share Total 2013 171,263 $ 45.54 $ 7.8 2014 — — — 2015 2,326,493 66.50 154.7 All shares repurchased have been retired. At December 31, 2015 , $93.4 million of the authorized amount remained available for repurchase of the Company's common stock. Subsequent to year-end, we repurchased 1,868,487 shares of common stock for $93.4 million , fully depleting the July 2015 authorization of $150 million . On February 25, 2016, PCA announced that its Board of Directors authorized the repurchase of an additional $200 million of the Company's outstanding common stock. Repurchases may be made from time to time in the open market or privately negotiated transactions in accordance with applicable securities regulations. The timing and amount of repurchases will be determined by the Company in its discretion based on factors such as PCA's stock price and market and business conditions. Accumulated Other Comprehensive Income (Loss) Changes in AOCI, net of taxes, by component follows (dollars in millions). Amounts in parentheses indicate losses. Foreign Currency Translation Adjustments Unrealized Loss On Treasury Locks, Net Unrealized Loss on Foreign Exchange Contracts Unfunded Employee Benefit Obligations Total Balance at December 31, 2014 $ (2.7 ) $ (24.7 ) $ (0.4 ) $ (126.1 ) $ (153.9 ) Other comprehensive income (loss) before reclassifications, net of tax (1.5 ) — — 14.0 12.5 Amounts reclassified from AOCI, net of tax 4.2 3.5 — 8.8 16.5 Net current-period other comprehensive income (loss) 2.7 3.5 — 22.8 29.0 Balance at December 31, 2015 $ — $ (21.2 ) $ (0.4 ) $ (103.3 ) $ (124.9 ) The following table presents information about reclassifications out of AOCI (dollars in millions). Amounts in parentheses indicate expenses in the Consolidated Statements of Income. Amounts Reclassified from AOCI Year Ended December 31 Details about AOCI Components 2015 2014 Affected Line Item in the Statement Where Net Income is Presented Foreign currency translation adjustments $ (4.2 ) $ — Other expense, net — — Tax benefit $ (4.2 ) $ — Net of tax Unrealized loss on treasury locks, net $ (5.7 ) $ (5.7 ) See (a) below 2.2 2.2 Tax benefit $ (3.5 ) $ (3.5 ) Net of tax Unfunded employee benefit obligations Amortization of prior service costs $ (5.6 ) $ (6.3 ) See (b) below Amortization of actuarial gains / (losses) (8.8 ) (0.7 ) See (b) below (14.4 ) (7.0 ) Total before tax 5.6 2.8 Tax benefit $ (8.8 ) $ (4.2 ) Net of tax ____________ (a) This AOCI component is included in interest expense, net. Amount relates to the amortization of the effective portion of treasury lock derivative instruments recorded in AOCI. The net amount of settlement gains or losses on derivative instruments included in AOCI to be amortized over the next 12 months is a net loss of $5.7 million ( $3.5 million after-tax). For a discussion of treasury lock derivative instrument activity, see Note 14 , Derivative Instruments and Hedging Activities , for additional information. (b) These AOCI components are included in the computation of net pension and postretirement benefit costs. See Note 11 , Employee Benefit Plans and Other Postretirement Benefits , for additional information.

Concentrations of Risk

Concentrations of Risk	12 Months Ended
	Dec. 31, 2015
Risks and Uncertainties [Abstract]
Concentration of Risk	Concentrations of Risk Our Paper segment has had a long-standing commercial and contractual relationship with Office Depot, our largest customer in the paper business. Office Depot agreed to be acquired by Staples, Inc. on February 4, 2015. The pending acquisition by Staples is subject to the satisfaction of certain conditions, including regulatory approval. This relationship exposes us to a significant concentration of business and financial risk. Our sales to Office Depot represented 9% of our total company sales, for both 2015 and 2014 , and about 45% of our Paper segment sales revenue for those periods. At December 31, 2015 and 2014 , we had $39.5 million and $52.6 million of accounts receivable due from Office Depot, respectively, which represents 6% and 8% of our total company receivables, respectively. Our agreement with Office Depot will continue to remain in effect after a merger or acquisition as to the office paper requirements of the legacy Office Depot business. However, we cannot predict how any merger or acquisition will affect the financial condition of the ultimate entity, the paper requirements of the legacy Office Depot business, the purchasing decisions of the ultimate entity or the effects on pricing or competition for office papers. In 2015, sales to Office Depot represented 45% of our Paper segment sales. If these sales are reduced, whether as a result of the future acquisition of Office Depot by Staples or otherwise, we would need to find new customers. We may not be able to fully replace any lost sales, and any new sales may be at lower prices or higher costs. Any significant deterioration in the financial condition of the ultimate entity affecting its ability to pay or any other change that affects its willingness to purchase our products will harm our business and results of operations. Labor At December 31, 2015 , we had approximately 13,000 employees and approximately 50% of these employees worked pursuant to collective bargaining agreements. Approximately 70% of our hourly employees are represented by unions. The majority of our unionized employees are represented by the United Steel Workers (USW), the International Brotherhood of Teamsters (IBT), the International Association of Machinists (IAM), and the Association of Western Pulp and Paper Workers (AWPPW). Approximately 10% of our employees work pursuant to collective bargaining agreements that will expire within the next twelve months.

Transactions With Related Parti

Transactions With Related Parties	12 Months Ended
	Dec. 31, 2015
Related Party Transactions [Abstract]
Transactions With Related Parties	Transactions With Related Parties Louisiana Timber Procurement Company, L.L.C. (LTP) is a variable-interest entity that is 50% owned by PCA and 50% owned by Boise Cascade Company (Boise Cascade). LTP procures sawtimber, pulpwood, residual chips, and other residual wood fiber to meet the wood and fiber requirements of PCA and Boise Cascade in Louisiana. PCA is the primary beneficiary of LTP, and has the power to direct the activities that most significantly affect the economic performance of LTP. Therefore, we consolidate 100% of LTP in our financial statements in our Corporate and Other segment. The carrying amounts of LTP's assets and liabilities (which relate primarily to non-inventory working capital items) on our Consolidated Balance Sheets were both $4.5 million at December 31, 2015 , and $5.2 million at December 31, 2014 . For 2015 , 2014 , and 2013, we recorded $88.8 million , $75.8 million , and $10.3 million , respectively, of LTP sales to Boise Cascade in "Net Sales" in the Consolidated Statements of Income and approximately the same amount of expenses in "Cost of Sales". For 2015 , 2014 , and 2013, fiber purchases from related parties were $20.7 million , $28.7 million , and $3.7 million , respectively. Most of these purchases related to chip and log purchases by LTP from Boise Cascade's wood products business. These purchases are recorded in "Cost of Sales" in the Consolidated Statements of Income.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Segment Information	Segment Information We report our business in three reportable segments: Packaging, Paper, and Corporate and Other. These segments represent distinct businesses that are managed separately because of differing products and services. Each of these businesses require distinct operating and marketing strategies. Packaging. We manufacture and sell a wide variety of corrugated packaging products, including conventional shipping containers used to protect and transport manufactured goods, multi-color boxes and displays with strong visual appeal that help to merchandise the packaged product in retail locations. In addition, we are a large producer of packaging for meat, fresh fruit and vegetables, processed food, beverages, and other industrial and consumer products. Paper. We manufacture and sell a range of white papers, including communication papers, and pressure sensitive papers, and market pulp. Our white papers can be manufactured as either commodity papers or specialty papers with specialized or custom features, such as colors, coatings, high brightness, or recycled content. We ship to customers both directly from our mills and through distribution centers. In 2015 , our sales to Office Depot, our largest paper segment customer, represented 45% of our Paper segment sales revenue. Corporate and Other. Our Corporate and Other segment includes corporate support staff services and related assets and liabilities, and foreign exchange gains and losses. This segment also includes transportation assets, such as rail cars and trucks, which we use to transport our products from some of our manufacturing sites and assets related to LTP. See Note 17 , Transactions With Related Parties , for more information related to LTP. Sales in this segment relate primarily to LTP and our rail and truck business. We provide transportation services not only to our own facilities but also, on a limited basis, to third parties when geographic proximity and logistics are favorable. Rail cars and trucks are generally leased. Each segments' profits and losses are measured on operating profits before interest expense and interest income. For many of these allocated expenses, the related assets and liabilities remain in the Corporate and Other segment. Segment sales to external customers by product line were as follows (dollars in millions): Year Ended December 31 2015 2014 2013 Packaging sales $ 4,477.3 $ 4,540.3 $ 3,431.7 Paper sales White papers 1,089.6 1,138.5 207.0 Market pulp 53.5 62.9 9.9 1,143.1 1,201.4 216.9 Corporate and Other 121.3 110.9 16.7 $ 5,741.7 $ 5,852.6 $ 3,665.3 Sales to foreign unaffiliated customers during the years ended December 31, 2015 , 2014 , and 2013 were $177.2 million , $378.8 million , and $162.4 million , respectively. At December 31, 2015, we do not have significant long-lived assets held by foreign operations. At December 31, 2014, the net carrying value of long-lived assets held by foreign operations, all of which were in our Packaging segment, was $12.4 million . The sales to foreign unaffiliated customers and the net carrying value of long-lived assets held by foreign operations decreased in 2015 as we completed the sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico on April 1, 2015. An analysis of operations by reportable segment is as follows (dollars in millions): Sales, net Operating Income (Loss) Depreciation, Capital Assets Year Ended December 31, 2015 Trade Inter- Total Packaging $ 4,474.1 $ 3.2 $ 4,477.3 $ 714.9 (a) $ 297.3 $ 250.3 $ 4,027.9 Paper 1,143.1 — 1,143.1 112.5 (b) 54.9 58.5 976.5 Corporate and Other 124.5 133.8 258.3 (77.4 ) (c) 4.3 5.7 280.2 Intersegment eliminations — (137.0 ) (137.0 ) — — — — $ 5,741.7 $ — $ 5,741.7 750.0 $ 356.5 $ 314.5 $ 5,284.6 Interest expense, net (85.5 ) Income before taxes $ 664.5 Sales, net Operating Income (Loss) Depreciation, Capital Assets Year Ended December 31, 2014 Trade Inter- Total Packaging $ 4,534.5 $ 5.8 $ 4,540.3 $ 663.2 (d) $ 323.0 $ 362.1 $ 4,105.3 Paper 1,201.4 — 1,201.4 135.4 50.6 51.7 968.6 Corporate and Other 116.7 144.9 261.6 (95.9 ) (e) 7.4 6.4 198.9 Intersegment eliminations — (150.7 ) (150.7 ) — — — — $ 5,852.6 $ — $ 5,852.6 702.7 $ 381.0 $ 420.2 $ 5,272.8 Interest expense, net (88.4 ) (f) Income before taxes $ 614.3 Sales, net Operating Income (Loss) Depreciation, Capital Assets Year Ended December 31, 2013 (g) Trade Inter- Total Packaging $ 3,431.3 $ 0.4 $ 3,431.7 $ 554.2 (h) $ 190.2 $ 222.2 $ 3,988.5 Paper 216.9 — 216.9 13.5 (i) 9.1 10.0 938.4 Corporate and Other 17.1 28.0 45.1 (85.8 ) (j) 2.5 2.2 269.3 Intersegment eliminations — (28.4 ) (28.4 ) — — — — $ 3,665.3 $ — $ 3,665.3 481.9 $ 201.8 $ 234.4 $ 5,196.2 Interest expense, net (58.3 ) (k) Income before taxes $ 423.6 ____________ (a) 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. (b) 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. (c) 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. (d) 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. (e) 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. (f) 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 . (g) On October 25, 2013, we acquired Boise Inc. (Boise). Our financial results include Boise subsequent to acquisition. (h) 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. (i) Includes $3.5 million of expense for acquisition inventory step-up and $1.9 million of income for integration-related and other costs. (j) Includes $17.2 million of acquisition-related costs and $17.9 million of integration-related and other costs. (k) 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. (l) 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.

Commitments, Guarantees, Indemn

Commitments, Guarantees, Indemnifications, and Legal Proceedings	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments, Guarantees, Indemnifications, and Legal Proceedings	Commitments, Guarantees, Indemnifications, and Legal Proceedings We have financial commitments and obligations that arise in the ordinary course of our business. These include long-term debt (discussed in Note 10 , Debt ), capital commitments, lease obligations, purchase commitments for goods and services, and legal proceedings (discussed below). Capital Commitments The Company had capital commitments of approximately $83.7 million and $94.7 million as of December 31, 2015 and 2014 , respectively, in connection with the expansion and replacement of existing facilities and equipment. Lease Obligations PCA leases space for certain of its facilities, cutting rights to approximately 83,000 acres of timberland, land for a fiber farm, and equipment, primarily vehicles and rolling stock. Remaining lease terms range from one to 15 years and may contain renewal options or escalation clauses. Substantially all lease agreements have fixed payment terms based on the passage of time. Some lease agreements provide us with the option to purchase the leased property. Additionally, some agreements contain renewal options averaging approximately six years. Some leases may require the Company to pay executory costs, which may include property taxes, maintenance and insurance. The minimum lease payments under non-cancelable operating leases with lease terms in excess of one year were as follows (dollars in millions): 2016 $ 54.4 2017 45.0 2018 36.9 2019 25.7 2020 17.2 Thereafter 69.2 Total $ 248.4 Total lease expense, including base rent on all leases and executory costs, such as insurance, taxes, and maintenance, for the years ended December 31, 2015 , 2014 , and 2013 , was $87.9 million , $85.6 million and $56.0 million , respectively. These costs are included in "Cost of sales" and "Selling, general, and administrative expenses" in our Consolidated Statements of Income. We had an insignificant amount of sublease rental income in the periods presented. PCA was obligated under capital leases covering buildings and machinery and equipment in the amount of $22.8 million and $23.9 million at December 31, 2015 and 2014 , respectively. Assets held under capital lease obligations were included in property, plant, and equipment as follows (dollars in millions): Year Ended December 31 2015 2014 Buildings $ 0.3 $ 0.3 Machinery and equipment 28.5 28.5 Total 28.8 28.8 Less accumulated amortization (12.2 ) (10.5 ) Total $ 16.6 $ 18.3 Amortization of assets under capital lease obligations is included in depreciation expense. The future minimum payments under capitalized leases at December 31, 2015 were as follows (dollars in millions): 2016 $ 2.7 2017 2.7 2018 2.7 2019 2.7 2020 2.7 Thereafter 20.4 Total minimum capital lease payments 33.9 Less amounts representing interest (11.1 ) Present value of net minimum capital lease payments 22.8 Less current maturities of capital lease obligations (1.2 ) Total long-term capital lease obligations $ 21.6 Interest expense related to capital lease obligations was $1.6 million during the year ended December 31, 2015 , and $1.6 million during both the years ended December 31, 2014 and 2013 . Purchase Commitments In the table below, we set forth our enforceable and legally binding purchase obligations as of December 31, 2015 . Some of the amounts are based on management's estimates and assumptions about these obligations, including their duration, the possibility of renewal, anticipated actions by third parties, and other factors. Because these estimates and assumptions are necessarily subjective, our actual payments may vary from those reflected in the table. Purchase orders made in the ordinary course of business are excluded below. Any amounts for which we are liable under purchase orders are reflected on the Consolidated Balance Sheets as accounts payable and accrued liabilities. These obligations relate to various purchase agreements for items such as minimum amounts of fiber and energy purchases over periods ranging from one year to 20 years. Total purchase commitments were as follows (dollars in millions): 2016 $ 95.3 2017 60.3 2018 28.0 2019 28.0 2020 23.4 Thereafter 77.0 Total $ 312.0 The Company purchased a total of $299.6 million , $265.9 million , and $61.7 million during the years ended December 31, 2015 , 2014 , and 2013 , respectively, under these purchase agreements. The increase in purchases The increase in purchases under these agreements in 2014, compared with 2013, relates to the acquisition of Boise in fourth quarter 2013. Environmental Liabilities The potential costs for various environmental matters are uncertain due to such factors as the unknown magnitude of possible cleanup costs, the complexity and evolving nature of governmental laws and regulations and their interpretations, and the timing, varying costs and effectiveness of alternative cleanup technologies. From 2006 through 2015, there were no significant environmental remediation costs at PCA's mills and corrugated plants. At December 31, 2015 , the Company had $24.3 million of environmental-related reserves recorded on its Consolidated Balance Sheet. Of the $24.3 million , approximately $15.8 million related to environmental-related asset retirement obligations discussed in Note 12 , Asset Retirement Obligations , and $8.5 million related to our estimate of other environmental contingencies. The Company recorded $7.9 million in "Accrued liabilities" and $16.4 million in "Other long-term liabilities" on the Consolidated Balance Sheet. Liabilities recorded for environmental contingencies are estimates of the probable costs based upon available information and assumptions. Because of these uncertainties, PCA’s estimates may change. The Company believes that it is not reasonably possible that future environmental expenditures for remediation costs and asset retirement obligations above the $24.3 million accrued as of December 31, 2015 , will have a material impact on its financial condition, results of operations, or cash flows. Guarantees and Indemnifications We provide guarantees, indemnifications, and other assurances to third parties in the normal course of our business. These include tort indemnifications, environmental assurances, and representations and warranties in commercial agreements. At December 31, 2015 , we are not aware of any material liabilities arising from any guarantee, indemnification, or financial assurance we have provided. If we determined such a liability was probable and subject to reasonable determination, we would accrue for it at that time. Legal proceedings During 2010, PCA and eight other U.S. and Canadian containerboard producers were named as defendants in five purported class action lawsuits filed in the United States District Court for the Northern District of Illinois, alleging violations of the Sherman Act. The lawsuits were consolidated in a single complaint under the caption Kleen Products LLC v Packaging Corp. of America et al. The consolidated complaint alleges that the defendants conspired to limit the supply of containerboard, and that the purpose and effect of the alleged conspiracy was to artificially increase prices of containerboard products during the period of August 2005 to October 2010 (the time of filing of the complaint). The complaint was filed as a class action suit on behalf of all purchasers of containerboard products during such period. In 2014, we settled the class action lawsuit for $17.6 million . These costs were recorded in "Other expense, net" in our Consolidated Statement of Income for the year ended December 31, 2014 . We are also a party to other legal actions arising in the ordinary course of our business. These legal actions include commercial liability claims, premises liability claims, and employment-related claims, among others. As of the date of this filing, we believe it is not reasonably possible that any of the legal actions against us will, either individually or in the aggregate, have a material adverse effect on our financial condition, results of operations, or cash flows.

Quarterly Results of Operations

Quarterly Results of Operations (Unaudited)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results of Operations (Unaudited)	Quarterly Results of Operations (unaudited, dollars in millions, except per-share and stock price information) Quarter 2015: First (a) Second (b) Third (c) Fourth (d) Total Net sales $ 1,425.7 $ 1,454.3 $ 1,470.8 $ 1,390.9 $ 5,741.7 Gross profit 277.0 317.6 328.3 285.0 1,208.0 Income from operations 157.1 197.6 219.4 175.9 750.0 Net income 90.8 114.0 127.8 104.3 436.8 Basic earnings per share 0.92 1.16 1.31 1.07 4.47 Diluted earnings per share 0.92 1.16 1.31 1.07 4.47 Stock price - high 84.88 78.98 73.60 70.04 84.88 Stock price - low 73.03 62.48 58.29 59.54 58.29 Quarter 2014: First (e) Second (f) Third (g) Fourth (h) Total Net sales $ 1,431.3 $ 1,468.4 $ 1,518.9 $ 1,434.0 $ 5,852.6 Gross profit 301.4 310.8 320.3 297.0 1,229.5 Income from operations 160.9 180.2 188.4 173.2 702.7 Net income 90.1 99.6 104.4 98.5 392.6 Basic earnings per share 0.92 1.01 1.06 1.00 3.99 Diluted earnings per share 0.92 1.01 1.06 1.00 3.99 Stock price - high 75.10 72.74 72.82 80.14 80.14 Stock price - low 61.35 65.00 63.11 57.06 57.06 ____________ Note: The sum of the quarters may not equal the total of the respective year’s earnings per share on either a basic or diluted basis due to changes in the weighted average shares outstanding throughout the year. (a) 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. (b) 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. (c) 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). (d) 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). (e) 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). (f) 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). (g) 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). (h) Includes $18.0 million of DeRidder restructuring charges ( $11.7 million after-tax or $0.12 per diluted share) and $6.4 million of integration-related and other costs ( $4.2 million after-tax or $0.04 per diluted share).

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2015
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event Subsequent to year-end, we repurchased 1,868,487 shares of common stock for $93.4 million , fully depleting the July 2015 authorization of $150 million . On February 25, 2016, PCA announced that its Board of Directors authorized the repurchase of an additional $200 million of the Company's outstanding common stock. Repurchases may be made from time to time in the open market or privately negotiated transactions in accordance with applicable securities regulations. The timing and amount of repurchases will be determined by the Company in its discretion based on factors such as PCA's stock price and market and business conditions.

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2015
Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts	Schedule II - Packaging Corporation of America - Valuation and Qualifying Accounts (dollars in millions). Description Balance Beginning of Year Acquired Reserves Charged to Expenses Deductions Balance End of Year Year ended December 31, 2015: Deducted from assets accounts: Allowance for doubtful accounts $ 4.9 $ — $ 0.9 $ (1.9 ) (a) $ 3.9 Reserve for customer deductions 6.4 — 46.2 (46.2 ) (b) 6.4 Deferred tax asset valuation allowance 1.7 — 4.5 (1.1 ) 5.1 Total $ 13.0 $ — $ 51.6 $ (49.2 ) $ 15.4 Year ended December 31, 2014: Deducted from assets accounts: Allowance for doubtful accounts $ 3.9 $ — $ 2.2 $ (1.2 ) (a) $ 4.9 Reserve for customer deductions 6.7 — 44.5 (44.8 ) (b) 6.4 Deferred tax asset valuation allowance 2.7 — 0.1 (1.1 ) 1.7 Total $ 13.3 $ — $ 46.8 $ (47.1 ) $ 13.0 Year ended December 31, 2013: Deducted from assets accounts: Allowance for doubtful accounts $ 1.9 $ — $ 2.8 $ (0.8 ) (a) $ 3.9 Reserve for customer deductions 3.4 3.4 39.5 (39.6 ) (b) 6.7 Deferred tax asset valuation allowance — 2.7 — — 2.7 Total $ 5.3 $ 6.1 $ 42.3 $ (40.4 ) $ 13.3 ________ (a) Consists primarily of uncollectable accounts written off, net of recoveries, during the year. (b) Consists primarily of discounts taken by customers during the year.

Summary of Significant Accoun30

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Consolidation	The consolidated financial statements include the accounts of PCA and its majority-owned subsidiaries after elimination of intercompany balances and transactions. Boise's results are included in our results subsequent to October 25, 2013 , the date of acquisition.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions about future events. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities, and reported amounts of revenues and expenses. These estimates and assumptions are based on management's best estimates and judgment. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment. We adjust such estimates and assumptions when facts and circumstances dictate. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Changes in these estimates will be reflected in the consolidated financial statements in future periods.
Revenue Recognition	Revenue Recognition We recognize revenue when the following criteria are met: persuasive evidence of an agreement exists, the customer takes title and assumes risk and rewards of ownership or services have been rendered, our price to the buyer is fixed or determinable, and collectability is reasonably assured. The timing of revenue recognition is dependent on transfer of title which is normally either on exit from our plants (i.e., shipping point) or on arrival at customer’s location (i.e., destination point). Shipping and handling billings to a customer are included in net sales. Shipping and handling costs, such as freight to our customers' destinations, are included in cost of sales. We present taxes collected from customers and remitted to governmental authorities on a net basis in our Consolidated Statements of Income.
Planned Major Maintenance Costs	Planned Major Maintenance Costs The Company accounts for its planned major maintenance activities in accordance with ASC 360, "Property, Plant, and Equipment," using the deferral method. All maintenance costs incurred during the year are expensed in the year in which the maintenance activity occurs.
Share-Based Compensation	Share-Based Compensation We recognize compensation expense for awards granted under the PCA long-term equity incentive plans based on the fair value on the grant date. We recognize the cost of the equity awards expected to vest over the period the awards vest. See Note 13 , Share-Based Compensation , for more information.
Research and Development	Research and Development Research and development costs are expensed as incurred.
Foreign Currency	Foreign Currency Local currencies are the functional currencies for our operations outside the United States. Assets and liabilities are remeasured into U.S. dollars using the exchange rates as of the Consolidated Balance Sheet date. Revenue and expense items are remeasured into U.S. dollars using an average exchange rate prevailing during the period. Any resulting translation adjustments are recorded in the Consolidated Statements of Comprehensive Income. The foreign exchange gain (loss) resulting from remeasuring transactions into the functional currencies is reported in the Consolidated Statements of Income.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents include all cash balances and highly liquid investments with a stated maturity of three months or less. Cash equivalents are stated at cost, which approximates market.
Trade Accounts Receivable, Allowance for Doubtful Accounts, and Customer Deductions	Trade Accounts Receivable, Allowance for Doubtful Accounts, and Customer Deductions Trade accounts receivable are stated at the amount we expect to collect. The collectability of our accounts receivable is based upon a combination of factors. In circumstances where a specific customer is unable to meet its financial obligations to PCA (e.g., bankruptcy filings, substantial downgrading of credit sources), a specific reserve for bad debts is recorded against amounts due to the Company to reduce the net recorded receivable to the amount the Company reasonably believes will be collected. For all other customers, reserves for bad debts are recognized based on historical collection experience. If collection experience deteriorates (i.e., higher than expected defaults or an unexpected material adverse change in a major customer’s ability to meet its financial obligations to the Company), the estimate of the recoverability of amounts due could be reduced by a material amount. We periodically review our allowance for doubtful accounts and adjustments to the valuation allowance are recorded as income or expense. Trade accounts receivable balances that remain outstanding after we have used reasonable collection efforts are written off through a charge to the valuation allowance and a credit to accounts receivable. At December 31, 2015 and 2014 , the allowance for doubtful accounts was $3.9 million and $4.9 million , respectively. The customer deductions reserve represents the estimated amount required for customer returns, allowances, and earned discounts. Based on the Company’s experience, customer returns, allowances, and earned discounts have averaged approximately 1% of gross selling price. Accordingly, PCA reserves 1% of its open customer accounts receivable balance for these items. The reserves for customer deductions of $6.4 million for both December 31, 2015 and 2014 , respectively, are also included as a reduction of the accounts receivable balance.
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities The Company records its derivatives, if any, in accordance with ASC 815, "Derivatives and Hedging." The guidance requires the Company to recognize derivative instruments as either assets or liabilities on the balance sheet at fair value. The accounting for changes in the fair value of a derivative depends on the intended use and designation of the derivative instrument. For a derivative designated as a fair value hedge, the gain or loss on the derivative is recognized in earnings in the period of change at fair value together with the offsetting gain or loss on the hedged item. For a derivative instrument designated as a cash flow hedge, the effective portion of the derivative’s gain or loss is initially reported as a component of accumulated other comprehensive income (loss) (AOCI) and is subsequently recognized in earnings when the hedged exposure affects earnings. The ineffective portion of the gain or loss is recognized in earnings. We were not party to any derivative-based arrangements at December 31, 2015 and 2014 .
Fair Value Measurements	Fair Value Measurements PCA measures the fair value of its financial instruments in accordance with ASC 820, "Fair Value Measurements and Disclosures." The guidance defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. It is determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, ASC 820 establishes the following hierarchy that prioritizes the inputs to valuation methodologies used to measure fair value: Level 1 — Valuations based on quoted prices for identical assets and liabilities in active markets. Level 2 — Valuations based on observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets and liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data. Level 3 — Valuations based on unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. Financial instruments measured at fair value on a recurring basis include the fair value of our pension and postretirement benefit assets and liabilities. See Note 11 , Employee Benefit Plans and Other Postretirement Benefits for more information. Other assets and liabilities measured and recognized at fair value on a nonrecurring basis include assets acquired and liabilities assumed in acquisitions and our asset retirement obligations. Given the nature of these assets and liabilities, evaluating their fair value from the perspective of a market participant is inherently complex. Assumptions and estimates about future values can be affected by a variety of internal and external factors. Changes in these factors may require us to revise our estimates and could require us to retroactively adjust provisional amounts that we recorded for the fair values of assets acquired and liabilities assumed in connection with business combinations. These adjustments could have a material effect on our financial condition and results of operations. See Note 3 , Acquisitions and Dispositions , and Note 12 , Asset Retirement Obligations , for more information.
Inventory Valuation	Inventory Valuation We value our raw materials, work in process, and finished goods inventories using lower of cost, as determined by the average cost method, or market. Supplies and materials are valued at the first-in, first-out (FIFO) or average cost methods.
Property, Plant, and Equipment	Property, Plant, and Equipment Property, plant, and equipment are recorded at cost. Cost includes expenditures for major improvements and replacements and the amount of interest cost associated with significant capital additions. Repairs and maintenance costs are expensed as incurred . When property and equipment are retired, sold, or otherwise disposed of, the asset's carrying amount and related accumulated depreciation are removed from the accounts and any gain or loss is included in "Net income" in our Consolidated Statements of Income.
Depreciation and Useful Life	Depreciation is computed on the straight-line basis over the estimated useful lives of the related assets. Assets under capital leases are depreciated on the straight-line method over the term of the lease or the useful life, if shorter. The following lives are used for the various categories of assets: Buildings and land improvements 5 to 40 years Machinery and equipment 3 to 25 years Trucks and automobiles 3 to 10 years Furniture and fixtures 3 to 20 years Computers and hardware 3 to 10 years Leasehold improvements Period of the lease or useful life, if shorter
Leases	Leases We assess lease classification as either capital or operating at lease inception or upon modification. We lease some of our locations, as well as other property and equipment, under operating leases. For purposes of determining straight-line rent expense, the lease term is calculated from the date of possession of the facility, including any periods of free rent and any renewal option periods that are reasonably assured of being exercised.
Long-Lived Asset Impairment	Long-Lived Asset Impairment Long-lived assets other than goodwill and other intangibles are reviewed for impairment in accordance with provisions of ASC 360, "Property, Plant and Equipment." In the event that facts and circumstances indicate that the carrying amount of any long-lived assets may be impaired, an evaluation of recoverability is performed. If an evaluation is required, the estimated future undiscounted cash flows associated with the asset (or group of assets) is compared to the assets (or group of assets) carrying amount to determine if a write-down to fair value is required.
Goodwill and Intangible Assets	Goodwill and Intangible Assets The Company has capitalized certain intangible assets, primarily goodwill, customer relationships, and trademarks and trade names, based on their estimated fair value at the date of acquisition. Amortization is provided for customer relationships on a straight-line basis over periods ranging from ten to 40 years, and trademarks and trade names over periods ranging from three to 20 years. Goodwill, which amounted to $544.0 million and $546.8 million for the years ended December 31, 2015 and 2014 , respectively, is not amortized but is subject to an annual impairment test in accordance with ASC 350, "Intangibles - Goodwill and Other." We test goodwill for impairment annually in the fourth quarter or sooner if events or changes in circumstances indicate that the carrying value of the asset may exceed fair value. Additionally, we evaluate the remaining useful lives of our finite-lived purchased intangible assets to determine whether any adjustments to the useful lives are necessary. The Company concluded that none of the goodwill or intangible assets were impaired in the 2015 , 2014 , and 2013 annual impairment tests. See Note 8 , Goodwill and Intangible Assets for additional information.
Pension and Postretirement Benefits	Pension and Postretirement Benefits Several estimates and assumptions are required to record pension costs and liabilities, including discount rate, return on assets, and longevity and service lives of employees. We review and update these assumptions annually unless a plan curtailment or other event occurs, requiring we update the estimates on an interim basis. While we believe the assumptions used to measure our pension and postretirement benefit obligations are reasonable, differences in actual experience or changes in assumptions may materially affect our pension and postretirement benefit obligations and future expense. See Note 11 , Employee Benefit Plans and Other Postretirement Benefits , for additional information. For postretirement health care plan accounting, the Company reviews external data and its own historical trends for health care costs to determine the health care cost trend rate assumption.
Environmental Matters	Environmental Matters Environmental expenditures that extend the life of the related property or mitigate or prevent future environmental contamination are capitalized. Liabilities are recorded for environmental contingencies when such costs are probable and reasonably estimable. These liabilities are adjusted as further information develops or circumstances change. Environmental expenditures related to existing conditions resulting from past or current operations from which no current or future benefit is discernible are expensed as incurred.
Asset Retirement Obligations	Asset Retirement Obligations The Company accounts for its retirement obligations related predominantly to landfill closure, wastewater treatment pond dredging, closed-site monitoring costs, and certain leasehold improvements under ASC 410, "Asset Retirement and Environmental Obligations," which requires recognition of legal obligations associated with the retirement of long-lived assets whether these assets are owned or leased. These legal obligations are recognized at fair value at the time that the obligations are incurred. When we record the liability, we capitalize the cost by increasing the carrying amount of the related long-lived asset which is amortized to expense over the useful life of the asset. See Note 12 , Asset Retirement Obligations , for additional information.
Deferred Financing Costs	Deferred Financing Costs PCA has capitalized certain costs related to obtaining its financing. These costs are amortized to interest expense using the effective interest rate method over the terms of the related financing, which range from five to ten years.
Cutting Rights and Fiber Farms	Cutting Rights and Fiber Farms We lease the cutting rights to approximately 83,000 acres of timberland and we lease 9,000 acres of land where we operate fiber farms as a source of future fiber supply. For our cutting rights and fiber farms, we capitalized the annual lease payments and reforestation costs associated with these leases. Costs are recorded as depletion when the timber or fiber is harvested and used in operations or sold to customers.
Deferred Software Costs	Deferred Software Costs PCA capitalizes costs related to the purchase and development of software which is used in its business operations. The costs attributable to these software systems are amortized over their estimated useful lives based on various factors such as the effects of obsolescence, technology, and other economic factors.
Income Taxes	Income Taxes PCA utilizes the liability method of accounting for income taxes whereby it recognizes deferred tax assets and liabilities for the future tax consequences of temporary differences between the tax basis of assets and liabilities and their reported amounts in the financial statements. Deferred tax assets will be reduced by a valuation allowance if, based upon management’s estimates, it is more likely than not that a portion of the deferred tax assets will not be realized in a future period. The estimates utilized in the recognition of deferred tax assets are subject to revision in future periods based on new facts or circumstances. PCA’s practice is to recognize interest and penalties related to unrecognized tax benefits in income tax expense.
Trade Agreements	Trade Agreements PCA regularly trades containerboard with other manufacturers primarily to reduce shipping costs. These agreements are entered into with other producers on an annual basis, pursuant to which both parties agree to ship an identical number of tons of containerboard to each other within the agreement period. These agreements lower transportation costs by allowing each party’s containerboard mills to ship containerboard to the other party’s closer corrugated products plant. PCA tracks each shipment to ensure that the other party’s shipments to PCA match PCA’s shipments to the other party during the agreement period. Such transfers are possible because containerboard is a commodity product with no distinguishing product characteristics. These transactions are accounted for at carrying value, and revenue is not recorded as the transactions do not represent the culmination of an earnings process. The transactions are recorded into inventory accounts, and no sale or income is recorded until such inventory is converted to a finished product and sold to an end-use customer.
New and Recently Adopted Accounting Pronouncements	New and Recently Adopted Accounting Standards In November 2015, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2015-17 (Topic 740): Balance Sheet Classification of Deferred Taxes. The new guidance conforms U.S. Generally Accepted Accounting Principles (GAAP) and International Financial Reporting Standards (IFRS) and eliminates the requirement to classify deferred taxes between current and noncurrent. The ASU requires all deferred tax assets and liabilities, along with any related valuation allowance, be classified as noncurrent on the balance sheet. We early adopted this guidance as of December 31, 2015. Related to the adoption of this guidance, we reclassified $75.7 million from current assets to long term liabilities on our December 31, 2014 Consolidated Balance Sheet to conform with the current period presentation. In July 2015, the FASB issued ASU 2015-11 (Topic 330): Simplifying the Measurement of Inventory, as part of its simplification initiative. Under the ASU, inventory is measured at the "lower of cost and net realizable value," which eliminates the other two options that currently exist for "market," including replacement cost and net realizable value less an approximately normal profit margin. No other changes were made to the current guidance on inventory measurement. The ASU is effective January 1, 2017, and we we do not expect the adoption of this update to have a material effect on our financial position or results of operations. In May 2015, the FASB issued ASU 2015-07 (Topic 820): Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent) , which removes the requirement to categorize within the fair value hierarchy all investments for which fair value is measured using the net asset value per share practical expedient. Further, the guidance removes the requirement to make certain disclosures for all investments that are eligible to be measured at fair value using the net asset value per share practical expedient. This ASU is effective for annual and interim periods beginning after December 15, 2015, and requires the new guidance be applied retrospectively to all prior periods presented. We do not believe the adoption of this update will have a material effect on our financial position and results of operations. In April 2015, the FASB issued ASU 2015-03 (Topic 835): Simplifying the Presentation of Debt Issuance Costs . This ASU conforms the presentation of debt issuance costs with that required for debt discounts under U.S. GAAP. Under the ASU, debt issuance costs are presented in the balance sheet as a direct deduction from the related debt liability rather than as an asset. The guidance is effective for annual and interim reporting periods beginning after December 15, 2015, and requires the new guidance be applied retrospectively to all prior periods presented. We do not believe the adoption of this update will have a material effect on our financial position and results of operations. In February 2015, the FASB issued ASU 2015-02 (Topic 810): Amendments to the Consolidation Analysis . This ASU makes targeted amendments to the current consolidation guidance and affects both the variable interest entity and voting interest entity consolidation models. The guidance is effective for annual reporting periods beginning after December 15, 2015. We do not believe the adoption of this update will have a material effect on our financial position and results of operations. In May 2014, the FASB issued ASU 2014-09 (Topic 606): Revenue from Contracts with Customers . This ASU amends the guidance for revenue recognition to replace numerous, industry-specific requirements and converges areas under this topic with those of the International Financial Reporting Standards. The ASU implements a five-step process for customer contract revenue recognition that focuses on transfer of control, as opposed to transfer of risk and rewards. The amendment also requires enhanced disclosures regarding the nature, amount, timing, and uncertainty of revenues and cash flows from contracts with customers. Entities can transition to the standard either retrospectively or as a cumulative-effect adjustment as of the date of adoption. In August 2015, the FASB issued ASU 2015-14: Revenue From Contracts with Customers (Topic 606): Deferral of the Effective Date. This ASU defers the effective date of the revenue standard, ASU 2014-09, by one year so that it is now effective for reporting periods beginning after December 15, 2017. We are still assessing the impact of ASU 2014-09, but we do not expect it to have a material effect on our financial position or results of operations. There were no other accounting standards recently issued that had or are expected to have a material impact on our financial position or results of operations.
Segment Information	Each segments' profits and losses are measured on operating profits before interest expense and interest income. For many of these allocated expenses, the related assets and liabilities remain in the Corporate and Other segment.

Summary of Significant Accoun31

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Components of Inventories	The components of inventories were as follows (dollars in millions): December 31 2015 2014 Raw materials $ 260.6 $ 261.9 Work in process 14.2 11.3 Finished goods 189.7 216.3 Supplies and materials 212.3 175.4 Inventories $ 676.8 $ 664.9
Property, Plant and Equipment (at cost)	Property, plant, and equipment consisted of the following (dollars in millions): December 31 2015 2014 Land and land improvements $ 146.4 $ 143.5 Buildings 640.9 654.6 Machinery and equipment 4,747.1 4,508.0 Construction in progress 119.1 154.8 Other 61.3 54.5 Property, plant, and equipment, at cost 5,714.8 5,515.4 Less accumulated depreciation (2,882.7 ) (2,657.8 ) Property, plant, and equipment, net $ 2,832.1 $ 2,857.6
Property, Plant and Equipment Estimated Useful Lives	Depreciation is computed on the straight-line basis over the estimated useful lives of the related assets. Assets under capital leases are depreciated on the straight-line method over the term of the lease or the useful life, if shorter. The following lives are used for the various categories of assets: Buildings and land improvements 5 to 40 years Machinery and equipment 3 to 25 years Trucks and automobiles 3 to 10 years Furniture and fixtures 3 to 20 years Computers and hardware 3 to 10 years Leasehold improvements Period of the lease or useful life, if shorter

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Computation of Basic and Diluted Income Per Common Share	The following table sets forth the computation of basic and diluted income per common share for the periods presented (dollars and shares in millions, except per share data). Year Ended December 31 2015 2014 2013 Numerator: Net income $ 436.8 $ 392.6 $ 441.3 Less: distributed and undistributed earnings allocated to participating securities (5.2 ) (5.7 ) — Net income attributable to common shareholders $ 431.6 $ 386.9 $ 441.3 Denominator: Weighted average basic common shares outstanding 96.6 97.0 96.6 Effect of dilutive securities 0.1 0.1 0.9 Diluted common shares outstanding 96.7 97.1 97.5 Basic income per common share $ 4.47 $ 3.99 $ 4.57 Diluted income per common share $ 4.47 $ 3.99 $ 4.52

Other Expense, Net (Tables)

Other Expense, Net (Tables)	12 Months Ended
	Dec. 31, 2015
Other Income and Expenses [Abstract]
Components of Other (Income) Expense	The components of other income (expense), net, were as follows (dollars in millions): Year Ended December 31 2015 2014 2013 Asset disposals and write-offs $ (14.0 ) $ (10.1 ) $ (13.2 ) Integration-related and other costs (a) (12.9 ) (20.0 ) (17.4 ) DeRidder restructuring (b) 7.1 (7.3 ) — Sale of St. Helens Paper Mill Site (c) 6.7 — — Refundable state tax credit (d) 3.6 — — Class action lawsuit settlement (e) — (17.6 ) — Acquisition-related costs (f) — — (17.2 ) Pension curtailment charges (g) — — (10.9 ) Other 2.8 (2.3 ) (0.3 ) Total $ (6.7 ) $ (57.3 ) $ (59.0 ) ___________ (a) Includes Boise acquisition integration-related and other costs, which primarily relate to severance, retention, travel, and professional fees. (b) 2015 and 2014 include amounts from restructuring activities at our mill in DeRidder, Louisiana including costs related to the conversion of the No. 3 newsprint machine to containerboard, our exit from the newsprint business, and other improvements. We completed the restructuring activities in first quarter 2015. In 2015, we recorded $7.1 million of income from vendor settlements. (c) 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. (d) 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, which was recorded as a benefit. (e) 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. (f) Includes $17.2 million of acquisition-related costs, primarily for professional fees related to transaction-advisory services and expenses related to financing the acquisition of Boise. (g) Includes $10.9 million of non-cash pension curtailment charges related to pension plan changes in which certain hourly corrugated plant and containerboard mill employees will transition from a defined benefit pension plan to a defined contribution (401k) plan.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Components of Consolidated Income Tax Provision	The following is an analysis of the components of the consolidated income tax provision (dollars in millions): 2015 2014 2013 Current income tax provision (benefit) - U.S. Federal $ 205.1 $ 185.1 $ 129.6 State and local 20.5 33.1 12.7 Foreign 0.4 0.9 0.3 Total current provision for taxes 226.0 219.1 142.6 Deferred - U.S. Federal (3.8 ) (5.0 ) (160.5 ) State and local 5.6 7.6 0.3 Foreign (0.1 ) — (0.1 ) Total deferred provision (benefit) for taxes 1.7 2.6 (160.3 ) Total provision (benefit) for taxes $ 227.7 $ 221.7 $ (17.7 )
Summary of Effective Tax Rate	The effective tax rate varies from the U.S. Federal statutory tax rate principally due to the following (dollars in millions): 2015 2014 2013 Provision computed at U.S. Federal statutory rate of 35% $ 232.6 $ 215.0 $ 148.3 Alternative fuel mixture and cellulosic biofuel producer credits — — (166.0 ) State and local taxes, net of federal benefit 20.0 20.5 13.6 Domestic manufacturers deduction (19.9 ) (16.5 ) (11.7 ) Other (5.0 ) 2.7 (1.9 ) Total $ 227.7 $ 221.7 $ (17.7 )
Summary of Operating Loss Carryforwards	The following details the scheduled expiration dates of our tax effected net operating loss (NOL) and other tax carryforwards at December 31, 2015 (dollars in millions): 2016 Through 2025 2026 Through 2035 Indefinite Total U.S. federal and non-U.S. NOLs $ — $ 70.9 $ — $ 70.9 State taxing jurisdiction NOLs 1.6 0.7 — 2.3 U.S. federal, non-U.S., and state tax credit carryforwards — 0.1 — 0.1 U.S. federal capital loss carryforwards 5.1 — — 5.1 Total $ 6.7 $ 71.7 $ — $ 78.4
Deferred Income Tax Assets and Liabilities	Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts for income tax purposes. Deferred income tax assets and liabilities at December 31 are summarized as follows (dollars in millions): December 31 2015 2014 Deferred tax assets: Accrued liabilities $ 18.3 $ 19.0 Employee benefits and compensation 32.5 44.2 Inventories 3.9 — Net operating loss carryforwards 73.2 85.2 Stock options and restricted stock 10.7 8.9 Pension and postretirement benefits 148.2 139.1 Derivatives 13.7 16.0 Capital loss, general business, foreign, and AMT credit carryforwards 5.2 1.8 Gross deferred tax assets $ 305.7 $ 314.2 Valuation allowance (a) (5.1 ) (1.7 ) Net deferred tax assets $ 300.6 $ 312.5 Deferred tax liabilities: Property, plant, and equipment $ (545.8 ) $ (531.6 ) Goodwill and intangible assets (101.8 ) (107.7 ) Inventories — (7.4 ) Total deferred tax liabilities $ (647.6 ) $ (646.7 ) Net deferred tax liabilities (b) $ (347.0 ) $ (334.2 ) ___________ (a) Deferred tax assets are reduced by a valuation allowance when it is more likely than not that some portion of the deferred tax assets will not be realized. The 2015 valuation allowance relates to capital losses. In 2014, of the $1.7 million valuation allowance, $1.1 million relates to foreign net operating loss carryforwards and credits and $0.6 million relates to capital losses. We do not expect to generate capital gains before the capital losses expire. If or when recognized, the tax benefits relating to the reversal of any of or all of the valuation allowance would be recognized as a benefit to income tax expense. (b) As of December 31, 2015 , we did not recognize U.S. deferred income taxes on our cumulative total of undistributed foreign earnings for our non-U.S. subsidiaries. We indefinitely reinvest our earnings in operations outside the United States. It is not practicable to determine the amount of unrecognized deferred tax liability on these undistributed earnings because the actual tax liability, if any, is dependent on circumstances existing when the repatriation occurs.
Summary of Uncertain Tax Position	The following table summarizes the changes related to PCA’s gross unrecognized tax benefits excluding interest and penalties (dollars in millions): 2015 2014 2013 Balance as of January 1 $ (4.4 ) $ (5.4 ) $ (111.3 ) Increase related to acquisition of Boise Inc. (a) — — (65.2 ) Increases related to prior years’ tax positions (2.8 ) (1.0 ) (0.1 ) Increases related to current year tax positions (0.4 ) (0.3 ) (1.5 ) Decreases related to prior years' tax positions (b) — 0.9 64.8 Settlements with taxing authorities (c) 0.7 0.5 106.2 Expiration of the statute of limitations 1.1 0.9 1.7 Balance at December 31 $ (5.8 ) $ (4.4 ) $ (5.4 ) ___________ (a) In 2013, PCA acquired $65.2 million of gross unrecognized tax benefits from Boise Inc. that related primarily to the taxability of the alternative energy tax credits. (b) The 2013 amount includes a $64.3 million gross decrease related to the taxability of the alternative energy tax credits claimed in 2009 excise tax returns by Boise Inc. For further discussion regarding these credits, see Note 7 , Alternative Energy Tax Credits . (c) The 2013 amount includes a $104.7 million gross decrease related to the conclusion of the Internal Revenue Service audit of PCA’s alternative energy tax credits. For further discussion regarding these credits, see Note 7 , Alternative Energy Tax Credits .

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Changes In the Carrying Amount of Goodwill	Changes in the carrying amount of our goodwill were as follows (dollars in millions): Packaging Paper Goodwill Balance at January 1, 2014 $ 472.9 $ 53.9 $ 526.8 Acquisitions (a) 12.2 — 12.2 Adjustments related to purchase accounting (b) 6.5 1.3 7.8 Balance at December 31, 2014 491.6 55.2 546.8 Sale of Hexacomb Europe and Mexico (c) (2.8 ) — (2.8 ) Balance at December 31, 2015 $ 488.8 $ 55.2 $ 544.0 ___________ (a) In April 2014, we acquired the assets of Crockett Packaging, a corrugated products manufacturer, for $21.2 million , before $0.7 million of working capital adjustments, and recorded $12.2 million of goodwill in our Packaging segment. (b) Adjustments relate primarily to the Boise acquisition, see Note 3 , Acquisitions and Dispositions , for more information. (c) During 2015, we sold the assets of Hexacomb Europe and Mexico, a corrugated products manufacturer, for $23.0 million and reduced goodwill in our Packaging segment by $2.8 million .
Components of Intangible Assets	The weighted average useful life, gross carrying amount, and accumulated amortization of our intangible assets were as follows (dollars in millions): As of December 31, 2015 As of December 31, 2014 Weighted Average Remaining Useful Life (in Years) Gross Accumulated Weighted Average Remaining Useful Life (in Years) Gross Accumulated Customer relationships 13.3 $ 311.5 $ 57.3 14.3 $ 311.5 $ 36.9 Trademarks and trade names 12.5 21.8 5.2 13.4 21.8 3.0 Other 1.2 0.2 0.2 2.2 0.2 0.1 Total intangible assets (excluding goodwill) 13.3 $ 333.5 $ 62.7 14.2 $ 333.5 $ 40.0

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2015
Accrued Liabilities, Current [Abstract]
Components of Accrued Liabilities	The components of accrued liabilities were as follows (dollars in millions): December 31, 2015 2014 Compensation and benefits $ 106.4 $ 130.8 Medical insurance and workers’ compensation 31.1 27.0 Franchise, property, sales and use taxes 16.0 17.5 Customer volume discounts and rebates 15.3 13.9 Severance, retention, and relocation 7.3 8.3 Environmental liabilities and asset retirement obligations 7.9 7.1 Other 9.5 15.4 Total $ 193.5 $ 220.0

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Summary of Debt	At December 31, 2015 and 2014 , our long-term debt and interest rates on that debt were as follows (dollars in millions): December 31, 2015 December 31, 2014 Amount Interest Rate Amount Interest Rate Revolving Credit Facility, due October 2018 $ — — % $ — — % Five-Year Term Loan, due October 2018 25.0 1.80 65.0 1.54 Seven-Year Term Loan, due October 2020 637.0 2.05 643.5 1.79 6.50% Senior Notes due March 2018 150.0 6.50 150.0 6.50 3.90% Senior Notes, net of discounts of $0.3 million as of both December 31, 2015 and 2014, respectively, due June 2022 399.7 3.90 399.7 3.90 4.50% Senior Notes, net of discount of $1.5 million and $1.7 million as of December 31, 2015 and 2014, respectively, due November 2023 698.5 4.50 698.3 4.50 3.65% Senior Notes, net of discount of $1.0 million and $1.1 million as of December 31, 2015 and 2014, due September 2024 399.0 3.65 398.9 3.65 Total 2,309.2 3.67 2,355.4 3.56 Less current portion 6.5 2.05 6.5 1.79 Total long-term debt $ 2,302.7 3.67 % $ 2,348.9 3.56 %

Employee Benefit Plans and Ot38

Employee Benefit Plans and Other Postretirement Plans (Tables)	12 Months Ended
	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Schedule of Obligations and Funded Status of Defined Benefit Pension and Postretirement Benefit Plans	The following table, which includes only company-sponsored defined benefit and other postretirement benefit plans, reconciles the beginning and ending balances of the projected benefit obligation and the fair value of plan assets. We recognize the unfunded status of these plans on the Consolidated Balance Sheets, and we recognize changes in funded status in the year changes occur through the Consolidated Statements of Comprehensive Income (dollars in millions): Pension Plans Postretirement Plans Year Ended December 31 Year Ended December 31 2015 2014 2015 2014 Change in Benefit Obligation Benefit obligation at beginning of period $ 1,129.6 $ 929.8 $ 31.9 $ 26.3 Service cost 24.0 22.7 1.7 1.6 Interest cost 46.2 45.9 1.2 1.2 Plan amendments 3.0 2.6 — — Actuarial (gain) loss (a) (75.7 ) 159.2 (11.4 ) 4.1 Special termination benefits — 0.3 — — Participant contributions — — 1.2 1.2 Benefits paid (34.6 ) (30.9 ) (3.2 ) (2.5 ) Benefit obligation at plan year end $ 1,092.5 $ 1,129.6 $ 21.4 $ 31.9 Accumulated benefit obligation portion of above $ 1,048.5 $ 1,078.6 Change in Fair Value of Plan Assets Plan assets at fair value at beginning of period $ 805.9 $ 772.1 $ — $ — Actual return on plan assets (8.1 ) 63.4 — — Company contributions 1.2 1.3 2.0 1.3 Participant contributions — — 1.2 1.2 Benefits paid (34.6 ) (30.9 ) (3.2 ) (2.5 ) Fair value of plan assets at plan year end $ 764.4 $ 805.9 $ — $ — Underfunded status $ (328.1 ) $ (323.7 ) $ (21.4 ) $ (31.9 ) Amounts Recognized on Consolidated Balance Sheets Current liabilities $ (0.9 ) $ (1.1 ) $ (1.1 ) $ (1.4 ) Noncurrent liabilities (327.2 ) (322.6 ) (20.3 ) (30.5 ) Accrued obligation recognized at December 31 $ (328.1 ) $ (323.7 ) $ (21.4 ) $ (31.9 ) Amounts Recognized in Accumulated Other Comprehensive (Income) Loss (Pre-Tax) Prior service cost $ 25.1 $ 27.6 $ 0.2 $ 0.3 Actuarial loss 149.4 172.6 (6.0 ) 5.5 Total $ 174.5 $ 200.2 $ (5.8 ) $ 5.8 ___________ (a) In 2015, the increase in the weighted average discount rate used to estimate our pension benefit obligations and changes in mortality assumptions from the Society of Actuaries resulted in an actuarial gain. The actuarial loss in 2014 was due primarily to a decrease in the weighted average discount rate and updated mortality assumptions.
Components of Net Periodic Benefit Costs and Other Comprehensive (Income) Loss (Pretax)	The components of net periodic benefit cost and other comprehensive (income) loss (pretax) were as follows (dollars in millions): Pension Plans Postretirement Plans Year Ended December 31 Year Ended December 31 2015 2014 2013 2015 2014 2013 Service cost $ 24.0 $ 22.7 $ 24.5 $ 1.7 $ 1.6 $ 2.1 Interest cost 46.2 45.9 21.5 1.2 1.2 1.3 Expected return on plan assets (53.1 ) (50.7 ) (21.4 ) — — — Special termination benefits — 0.3 — — — — Net amortization of unrecognized amounts Prior service cost 5.5 6.5 6.2 0.1 (0.2 ) (0.4 ) Actuarial loss 8.7 0.6 4.7 0.1 0.1 0.5 Curtailment loss (a) — — 10.9 — — — Net periodic benefit cost $ 31.3 $ 25.3 $ 46.4 $ 3.1 $ 2.7 $ 3.5 Changes in plan assets and benefit obligations recognized in other comprehensive (income) loss Actuarial net (gain) loss $ (14.5 ) $ 146.4 $ (58.7 ) $ (11.4 ) $ 4.2 $ (7.8 ) Prior service cost 3.0 2.6 13.8 — — — Amortization of prior service cost (5.5 ) (6.5 ) (6.2 ) (0.1 ) 0.2 0.4 Amortization of actuarial loss (8.7 ) (0.6 ) (4.7 ) (0.1 ) (0.1 ) (0.5 ) Curtailment loss (a) — — (10.9 ) — — — Total recognized in other comprehensive (income) loss (b) (25.7 ) 141.9 (66.7 ) (11.6 ) 4.3 (7.9 ) Total recognized in net periodic benefit cost and other comprehensive (income) loss - pretax $ 5.6 $ 167.2 $ (20.3 ) $ (8.5 ) $ 7.0 $ (4.4 ) ___________ (a) In 2013, we recognized curtailment losses in "Other expense, net" in the Consolidated Statements of Income for recent USW negotiations, resulting in the bifurcation of the active USW population between those grandfathered in the current formula (with continued accruals) and non-grandfathered in the current formula (frozen benefits at the contract date). (b) Accumulated losses in excess of 10% of the greater of the projected benefit obligation or the market-related value of assets will be recognized on a straight-line basis over the average remaining service period of active employees, which is between seven to ten years, to the extent that losses are not offset by gains in subsequent years. The estimated net loss and prior service cost that will be amortized from "Accumulated other comprehensive loss" into pension expense in 2016 is $10.5 million .
Weighted-Average Assumptions Used To Determine Benefit Obligations and Net Periodic Benefit Cost	The following table presents the assumptions used in the measurement of our benefits obligations: Pension Plans Postretirement Plans December 31 December 31 2015 2014 2013 2015 2014 2013 Weighted-Average Assumptions Used to Determine Benefit Obligations at December 31 Discount rate 4.51% 4.14% 5.00% 4.35% 3.95% 4.85% Rate of compensation increase 4.00% 4.00% 4.00% N/A N/A N/A Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost for the Years Ended December 31 Discount rate 4.14% 5.00% 4.57% 3.95% 4.85% 4.00% Expected return on plan assets 6.73% 6.69% 6.53% N/A N/A N/A Rate of compensation increase 4.00% 4.00% 4.00% N/A N/A N/A
Assumed Health Care Cost Trend Rates For Postretirement Benefits	Health Care Cost Trend Rate Assumptions. PCA assumed health care cost trend rates for its postretirement benefits plans were as follows: 2015 2014 2013 Health care cost trend rate assumed for next year 7.60% 7.75% 7.75% Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) 4.50% 5.00% 5.00% Year that the rate reaches the ultimate trend rate 2024 2023 2020
Schedule of Effects of One-Percentage Point Change In Assumed Health Care Cost Trend Rates on Postretirement Benefits	A one-percentage point change in assumed health care cost trend rates would have the following effects on the 2015 postretirement benefit obligation and the 2015 net post retirement benefit cost (dollars in millions): 1-Percentage Point Increase 1-Percentage Point Decrease Effect on postretirement benefit obligation $ 0.8 $ (0.7 ) Effect on net postretirement benefit cost — (0.1 )
Schedule of Pension Plans' Assets Investment Policies and Strategies	ension plans were invested in the following classes of securities at December 31, 2015 and 2014 : Percentage of Fair Value 2015 2014 Fixed income securities 55 % 54 % International equity securities 22 23 Domestic equity securities 20 20 Real estate securities 1 1 Other 2 2
Schedule of Pension Plans' Assets Fair Value Measured On a Recurring Basis	The following tables set forth, by level within the fair value hierarchy, discussed in Note 2 , Summary of Significant Accounting Policies , the pension plan assets, by major asset category, at fair value at December 31, 2015 and 2014 (dollars in millions): Fair Value Measurements at December 31, 2015 Asset Category Quoted Prices in Active Markets for Identical Significant Other Observable Significant Total Short-term investments (a) $ — $ 4.1 $ — $ 4.1 Mutual funds (b): Domestic equities 47.1 — — 47.1 International equities 50.7 — — 50.7 Real estate 8.5 — — 8.5 Fixed income 156.5 — — 156.5 Common/collective trust funds (a): Domestic equities — 104.4 — 104.4 International equities — 121.6 — 121.6 Fixed income — 263.0 — 263.0 Private equity securities (c) — — 6.4 6.4 Total securities at fair value $ 262.8 $ 493.1 $ 6.4 $ 762.3 Receivables and accrued expenses 2.1 Total fair value of plan assets $ 764.4 Fair Value Measurements at December 31, 2014 Asset Category Quoted Prices in Active Markets for Identical Significant Other Observable Significant Total Short-term investments (a) $ — $ 1.8 $ — $ 1.8 Mutual funds (b): Domestic equities 38.2 — — 38.2 International equities 49.9 — — 49.9 Real estate 8.9 — — 8.9 Fixed income 178.2 — — 178.2 Common/collective trust funds (a): Domestic equities — 122.3 — 122.3 International equities — 137.8 — 137.8 Fixed income — 259.3 — 259.3 Private equity securities (c) — — 8.1 8.1 Total securities at fair value $ 275.2 $ 521.2 $ 8.1 $ 804.5 Receivables and accrued expenses 1.4 Total fair value of plan assets $ 805.9 ____________ (a) Investments in common/collective trust funds valued using net asset values (NAV) provided by the administrator of the funds. We use NAV as a practical expedient to fair value. The NAV is based on the value of the underlying assets owned by the fund, minus its liabilities, and then divided by the number of units outstanding. While the underlying assets are actively traded on an exchange, the funds are not. There are currently no redemption restrictions on these investments. There are certain funds with one-day redeemable notice. (b) Investments in mutual funds valued at quoted market values on the last business day of the fiscal year. (c) Investments in this category are invested in the Pantheon Global Secondary Fund IV, LP. The fund specializes in investments in the private equity secondary market and occasionally directly in private companies to maximize capital growth. Fund investments are carried at fair value as determined quarterly using the market approach to estimate the fair value of private investments. The market approach utilizes prices and other relevant information generated by market transactions, type of security, size of the position, degree of liquidity, restrictions on the disposition, latest round of financing data, current financial position, and operating results, among other factors. In circumstances where fair values are not provided with respect to any of the company's fund investments, the investment advisor will seek to determine the fair value of such investments based on information provided by the general partners or managers of such funds or from other sources. Audited financial statements are provided by fund management annually. Notwithstanding the above, the variety of valuation bases adopted and quality of management data of the ultimate underlying investee companies means that there are inherent difficulties in determining the value of the investments. Amounts realized on the sale of these investments may differ from the calculated values. Boise had originally committed to a $15.0 million investment, with $5.0 million of the commitment unfunded at December 31, 2015 .
Summary of Changes in Pension Plans' Level 3 Assets	The following table sets forth a summary of changes in the fair value of the pension plans' Level 3 assets for the year ended December 31, 2015 (dollars in millions): 2015 Balance, beginning of year $ 8.1 Sales (1.8 ) Unrealized gain 0.1 Balance, end of year $ 6.4
Schedule of Estimated Benefit Payments	The following are estimated benefit payments to be paid to current plan participants by year (dollars in millions). Qualified pension benefit payments are paid from plan assets, while nonqualified pension benefit payments are paid by the Company. Pension Plans Postretirement Plans 2016 $ 37.8 $ 1.1 2017 40.9 1.1 2018 44.8 1.3 2019 48.6 1.3 2020 52.4 1.5 2021 - 2025 312.7 7.9

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2015
Asset Retirement Obligation [Abstract]
Changes to Asset Retirement Obligation	The following table describes changes to the asset retirement obligation liability (dollars in millions): Year Ended December 31 2015 2014 Asset retirement obligation at beginning of period $ 37.0 $ 32.0 Sale of St. Helens (a) (11.2 ) — Accretion expense 2.1 1.0 Payments (1.6 ) (0.1 ) Revisions in estimated cash flows 0.2 — Liabilities incurred (0.3 ) — Acquisition — 4.1 Asset retirement obligation at end of period $ 26.2 $ 37.0

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2015
Share-based Compensation [Abstract]
Summary of Restricted Stock Activity	A summary of the Company’s restricted stock activity follows: 2015 2014 2013 Shares Weighted Average Grant- Date Fair Value Shares Weighted Average Grant- Date Fair Value Shares Weighted Average Grant- Date Fair Value Restricted stock at January 1 1,184,299 $ 41.71 1,463,694 $ 31.48 1,771,664 $ 23.44 Granted 218,957 65.16 229,489 70.24 331,053 51.99 Vested (a) (389,481 ) 32.77 (507,222 ) 26.29 (605,458 ) 19.54 Forfeitures (5,981 ) 66.42 (1,662 ) 61.05 (33,565 ) 24.76 Restricted stock at December 31 1,007,794 $ 49.47 1,184,299 $ 41.71 1,463,694 $ 31.48 ___________ (a) The total fair value of awards upon vesting for the years ended December 31, 2015 , 2014 , and 2013 was $26.3 million , $36.4 million , and $29.5 million , respectively .
Summary of Performance Units Activity	The awards are valued at the closing price of the Company’s stock on the grant date and expensed over the requisite service period based on the most probable number of awards expected to vest. 2015 2014 2013 Units Weighted Average Grant- Date Fair Value Units Weighted Average Grant- Date Fair Value Units Weighted Average Grant-Date Fair Value Performance units at January 1 127,489 $ 58.25 70,600 $ 47.83 — $ — Granted 53,102 65.04 56,889 71.19 70,600 47.83 Vested (a) (4,916 ) 71.19 — — — — Forfeitures — — — — — — Performance units at December 31 175,675 $ 59.94 127,489 $ 58.25 70,600 $ 47.83
Compensation Expense For Restricted Stock and Performance Units	Compensation expense for share-based awards recognized in the Consolidated Statements of Income, net of forfeitures was as follows (dollars in millions): Year Ended December 31 2015 2014 2013 Restricted stock $ 15.2 $ 13.8 $ 14.3 Performance units 3.0 1.8 0.5 Impact on income before income taxes 18.2 15.6 14.8 Income tax benefit (7.1 ) (6.1 ) (5.8 ) Impact on net income $ 11.1 $ 9.5 $ 9.0
Unrecognized Compensation For Restricted Stock and Performance Units	The unrecognized compensation expense for all share-based awards was as follows (dollars in millions): December 31, 2015 Unrecognized Compensation Expense Remaining Weighted Average Recognition Period (in years) Restricted stock $ 26.6 2.5 Performance units 6.2 2.8 Total unrecognized share-based compensation expense $ 32.8 2.6

Derivative Instruments and He41

Derivative Instruments and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Impact of Derivative Instruments On Statements of Income and Accumulated OCI	The impact of derivative instruments on the consolidated statements of income and accumulated OCI was as follows (dollars in millions): Net 2015 2014 Treasury locks, net of tax $ (21.2 ) $ (24.7 ) Gain (Loss) Reclassified Location 2015 2014 2013 Amortization of treasury locks (included in interest expense, net) $ (5.7 ) $ (5.7 ) $ (5.7 )

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Share Repurchase Program	Share repurchase activity follows (in millions, except share and per share amounts). Shares Weighted Average Price Per Share Total 2013 171,263 $ 45.54 $ 7.8 2014 — — — 2015 2,326,493 66.50 154.7
Components of Changes in Accumulated Other Comprehensive Income (AOCI)	Changes in AOCI, net of taxes, by component follows (dollars in millions). Amounts in parentheses indicate losses. Foreign Currency Translation Adjustments Unrealized Loss On Treasury Locks, Net Unrealized Loss on Foreign Exchange Contracts Unfunded Employee Benefit Obligations Total Balance at December 31, 2014 $ (2.7 ) $ (24.7 ) $ (0.4 ) $ (126.1 ) $ (153.9 ) Other comprehensive income (loss) before reclassifications, net of tax (1.5 ) — — 14.0 12.5 Amounts reclassified from AOCI, net of tax 4.2 3.5 — 8.8 16.5 Net current-period other comprehensive income (loss) 2.7 3.5 — 22.8 29.0 Balance at December 31, 2015 $ — $ (21.2 ) $ (0.4 ) $ (103.3 ) $ (124.9 )
Reclassifications Out of Accumulated Other Comprehensive Income (AOCI)	The following table presents information about reclassifications out of AOCI (dollars in millions). Amounts in parentheses indicate expenses in the Consolidated Statements of Income. Amounts Reclassified from AOCI Year Ended December 31 Details about AOCI Components 2015 2014 Affected Line Item in the Statement Where Net Income is Presented Foreign currency translation adjustments $ (4.2 ) $ — Other expense, net — — Tax benefit $ (4.2 ) $ — Net of tax Unrealized loss on treasury locks, net $ (5.7 ) $ (5.7 ) See (a) below 2.2 2.2 Tax benefit $ (3.5 ) $ (3.5 ) Net of tax Unfunded employee benefit obligations Amortization of prior service costs $ (5.6 ) $ (6.3 ) See (b) below Amortization of actuarial gains / (losses) (8.8 ) (0.7 ) See (b) below (14.4 ) (7.0 ) Total before tax 5.6 2.8 Tax benefit $ (8.8 ) $ (4.2 ) Net of tax ____________ (a) This AOCI component is included in interest expense, net. Amount relates to the amortization of the effective portion of treasury lock derivative instruments recorded in AOCI. The net amount of settlement gains or losses on derivative instruments included in AOCI to be amortized over the next 12 months is a net loss of $5.7 million ( $3.5 million after-tax). For a discussion of treasury lock derivative instrument activity, see Note 14 , Derivative Instruments and Hedging Activities , for additional information. (b) These AOCI components are included in the computation of net pension and postretirement benefit costs. See Note 11 , Employee Benefit Plans and Other Postretirement Benefits , for additional information.

Segment Informaiton (Tables)

Segment Informaiton (Tables)	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Revenue from External Customers by Product Line	Segment sales to external customers by product line were as follows (dollars in millions): Year Ended December 31 2015 2014 2013 Packaging sales $ 4,477.3 $ 4,540.3 $ 3,431.7 Paper sales White papers 1,089.6 1,138.5 207.0 Market pulp 53.5 62.9 9.9 1,143.1 1,201.4 216.9 Corporate and Other 121.3 110.9 16.7 $ 5,741.7 $ 5,852.6 $ 3,665.3
Analysis of Operations by Reportable Segment	An analysis of operations by reportable segment is as follows (dollars in millions): Sales, net Operating Income (Loss) Depreciation, Capital Assets Year Ended December 31, 2015 Trade Inter- Total Packaging $ 4,474.1 $ 3.2 $ 4,477.3 $ 714.9 (a) $ 297.3 $ 250.3 $ 4,027.9 Paper 1,143.1 — 1,143.1 112.5 (b) 54.9 58.5 976.5 Corporate and Other 124.5 133.8 258.3 (77.4 ) (c) 4.3 5.7 280.2 Intersegment eliminations — (137.0 ) (137.0 ) — — — — $ 5,741.7 $ — $ 5,741.7 750.0 $ 356.5 $ 314.5 $ 5,284.6 Interest expense, net (85.5 ) Income before taxes $ 664.5 Sales, net Operating Income (Loss) Depreciation, Capital Assets Year Ended December 31, 2014 Trade Inter- Total Packaging $ 4,534.5 $ 5.8 $ 4,540.3 $ 663.2 (d) $ 323.0 $ 362.1 $ 4,105.3 Paper 1,201.4 — 1,201.4 135.4 50.6 51.7 968.6 Corporate and Other 116.7 144.9 261.6 (95.9 ) (e) 7.4 6.4 198.9 Intersegment eliminations — (150.7 ) (150.7 ) — — — — $ 5,852.6 $ — $ 5,852.6 702.7 $ 381.0 $ 420.2 $ 5,272.8 Interest expense, net (88.4 ) (f) Income before taxes $ 614.3 Sales, net Operating Income (Loss) Depreciation, Capital Assets Year Ended December 31, 2013 (g) Trade Inter- Total Packaging $ 3,431.3 $ 0.4 $ 3,431.7 $ 554.2 (h) $ 190.2 $ 222.2 $ 3,988.5 Paper 216.9 — 216.9 13.5 (i) 9.1 10.0 938.4 Corporate and Other 17.1 28.0 45.1 (85.8 ) (j) 2.5 2.2 269.3 Intersegment eliminations — (28.4 ) (28.4 ) — — — — $ 3,665.3 $ — $ 3,665.3 481.9 $ 201.8 $ 234.4 $ 5,196.2 Interest expense, net (58.3 ) (k) Income before taxes $ 423.6 ____________ (a) 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. (b) 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. (c) 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. (d) 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. (e) 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. (f) 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 . (g) On October 25, 2013, we acquired Boise Inc. (Boise). Our financial results include Boise subsequent to acquisition. (h) 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. (i) Includes $3.5 million of expense for acquisition inventory step-up and $1.9 million of income for integration-related and other costs. (j) Includes $17.2 million of acquisition-related costs and $17.9 million of integration-related and other costs. (k) 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. (l) 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.

Commitments, Guarantees, Inde44

Commitments, Guarantees, Indemnifications, and Legal Proceedings (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Schedule of Minimum Lease Payments Under Non-Cancelable Operating Leases	The minimum lease payments under non-cancelable operating leases with lease terms in excess of one year were as follows (dollars in millions): 2016 $ 54.4 2017 45.0 2018 36.9 2019 25.7 2020 17.2 Thereafter 69.2 Total $ 248.4
Schedule of Assets Held Under Capital Lease Obligations	Assets held under capital lease obligations were included in property, plant, and equipment as follows (dollars in millions): Year Ended December 31 2015 2014 Buildings $ 0.3 $ 0.3 Machinery and equipment 28.5 28.5 Total 28.8 28.8 Less accumulated amortization (12.2 ) (10.5 ) Total $ 16.6 $ 18.3
Schedule of Future Minimum Payments Under Capitalized Leases	The future minimum payments under capitalized leases at December 31, 2015 were as follows (dollars in millions): 2016 $ 2.7 2017 2.7 2018 2.7 2019 2.7 2020 2.7 Thereafter 20.4 Total minimum capital lease payments 33.9 Less amounts representing interest (11.1 ) Present value of net minimum capital lease payments 22.8 Less current maturities of capital lease obligations (1.2 ) Total long-term capital lease obligations $ 21.6
Schedule Of Purchase Commitments	Total purchase commitments were as follows (dollars in millions): 2016 $ 95.3 2017 60.3 2018 28.0 2019 28.0 2020 23.4 Thereafter 77.0 Total $ 312.0

Quarterly Results of Operatio45

Quarterly Results of Operations (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Summary of Quarterly Financial Data	Quarter 2015: First (a) Second (b) Third (c) Fourth (d) Total Net sales $ 1,425.7 $ 1,454.3 $ 1,470.8 $ 1,390.9 $ 5,741.7 Gross profit 277.0 317.6 328.3 285.0 1,208.0 Income from operations 157.1 197.6 219.4 175.9 750.0 Net income 90.8 114.0 127.8 104.3 436.8 Basic earnings per share 0.92 1.16 1.31 1.07 4.47 Diluted earnings per share 0.92 1.16 1.31 1.07 4.47 Stock price - high 84.88 78.98 73.60 70.04 84.88 Stock price - low 73.03 62.48 58.29 59.54 58.29 Quarter 2014: First (e) Second (f) Third (g) Fourth (h) Total Net sales $ 1,431.3 $ 1,468.4 $ 1,518.9 $ 1,434.0 $ 5,852.6 Gross profit 301.4 310.8 320.3 297.0 1,229.5 Income from operations 160.9 180.2 188.4 173.2 702.7 Net income 90.1 99.6 104.4 98.5 392.6 Basic earnings per share 0.92 1.01 1.06 1.00 3.99 Diluted earnings per share 0.92 1.01 1.06 1.00 3.99 Stock price - high 75.10 72.74 72.82 80.14 80.14 Stock price - low 61.35 65.00 63.11 57.06 57.06 ____________ Note: The sum of the quarters may not equal the total of the respective year’s earnings per share on either a basic or diluted basis due to changes in the weighted average shares outstanding throughout the year. (a) 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. (b) 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. (c) 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). (d) 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). (e) 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). (f) 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). (g) 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). (h) Includes $18.0 million of DeRidder restructuring charges ( $11.7 million after-tax or $0.12 per diluted share) and $6.4 million of integration-related and other costs ( $4.2 million after-tax or $0.04 per diluted share).

Nature of Operations and Basi46

Nature of Operations and Basis of Presentation - Additional Information (Detail) employee in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2015employee	Dec. 31, 2014USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of employees of PCA | employee	13
Number of reportable segments	3
New Accounting Pronouncement, Early Adoption, Effect [Member]
New Accounting Pronouncement, Early Adoption [Line Items]
Deferred tax asset net reclassified from current to non-current | $		$ 75.7

Summary of Significant Accoun47

Summary of Significant Accounting Policies - Additional Information (Details) $ in Millions	3 Months Ended															12 Months Ended
	Dec. 31, 2015USD ($)		Sep. 30, 2015USD ($)	[2]	Jun. 30, 2015USD ($)	[3]	Mar. 31, 2015USD ($)	[4]	Dec. 31, 2014USD ($)	Sep. 30, 2014USD ($)	[5]	Jun. 30, 2014USD ($)	[6]	Mar. 31, 2014USD ($)	[7]	Dec. 31, 2015USD ($)a	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)
Summary of Significant Accounting Policies [Line Items]
Research and development costs																$ 13.1	$ 12.3	$ 11.5
Cash and cash equivalents	$ 184.2								$ 124.9							184.2	124.9	191	$ 207.4
Cash equivalents	140.9								79.9							140.9	79.9
Allowance for doubtful accounts	3.9								4.9							$ 3.9	4.9
Customer returns, allowances and earned discounts as a percentage of gross selling price																1.00%
Reserve for customer accounts receivable, percentage																1.00%
Reserve for customer deductions																$ 6.4	6.4
Net income	104.3	[1]	$ 127.8		$ 114		$ 90.8		98.5	$ 104.4		$ 99.6		$ 90.1		436.8	392.6	441.3
Inventories	676.8								664.9							676.8	664.9
Retained earnings	1,317.3								1,242.2							1,317.3	1,242.2
Interest capitalization, construction in progress																$ 2	$ 2.8	1.7
Intangible asset, useful life, in years																13 years 2 months 40 days	14 years 2 months 8 days
Goodwill	544								546.8							$ 544	$ 546.8	526.8
Area leased under timberland cutting rights (acres) | a																83,000
Area leased where fiber farms are operated (acres) | a																9,000
Software amortization expense																$ 3	2.9	1.1
Minimum
Summary of Significant Accounting Policies [Line Items]
Term of senior credit facilities and notes, in years																5
Maximum
Summary of Significant Accounting Policies [Line Items]
Term of senior credit facilities and notes, in years																10
Foreign operations
Summary of Significant Accounting Policies [Line Items]
Cash and cash equivalents	3.1								10.4							$ 3.1	$ 10.4
Customer Relationships
Summary of Significant Accounting Policies [Line Items]
Intangible asset, useful life, in years																13 years 4 months	14 years 3 months
Customer Relationships | Minimum
Summary of Significant Accounting Policies [Line Items]
Intangible asset, useful life, in years																10 years
Customer Relationships | Maximum
Summary of Significant Accounting Policies [Line Items]
Intangible asset, useful life, in years																40 years
Trademarks and Trade Names
Summary of Significant Accounting Policies [Line Items]
Intangible asset, useful life, in years																12 years 5 months 33 days	13 years 4 months 28 days
Trademarks and Trade Names | Minimum
Summary of Significant Accounting Policies [Line Items]
Intangible asset, useful life, in years																3 years
Trademarks and Trade Names | Maximum
Summary of Significant Accounting Policies [Line Items]
Intangible asset, useful life, in years																20 years
Cutting Rights and Fiber Farms
Summary of Significant Accounting Policies [Line Items]
Depletion expense																$ 7	$ 7.3	$ 2.5
Other Long-Term Assets
Summary of Significant Accounting Policies [Line Items]
Unamortized deferred financing costs	12.3								14.1							12.3	14.1
Net capitalized software costs	6.9								6.8							6.9	6.8
Other Long-Term Assets | Cutting Rights and Fiber Farms
Summary of Significant Accounting Policies [Line Items]
Long-term lease costs capitalization (Cutting rights and Fiber farms)	$ 40.2								$ 38							$ 40.2	$ 38
[1]	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).
[2]	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).
[3]	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.
[4]	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.
[5]	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).
[6]	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).
[7]	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).

Summary of Significant Accoun48

Summary of Significant Accounting Policies - Components of Inventories (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Raw materials	$ 260.6	$ 261.9
Work in process	14.2	11.3
Finished goods	189.7	216.3
Supplies and materials	212.3	175.4
Inventories	$ 676.8	$ 664.9

Summary of Significant Accoun49

Summary of Significant Accounting Policies - Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, at cost	$ 5,714.8	$ 5,515.4
Less accumulated depreciation	(2,882.7)	(2,657.8)
Property, plant, and equipment, net	2,832.1	2,857.6
Depreciation [Abstract]
Depreciation expense	323	348.2	$ 191.2
Incremental depreciation	9	42
Land and Land Improvements
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, at cost	146.4	143.5
Buildings
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, at cost	640.9	654.6
Machinery and Equipment
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, at cost	4,747.1	4,508
Construction in Progress
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, at cost	119.1	154.8
Other
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, at cost	$ 61.3	$ 54.5

Summary of Significant Accoun50

Summary of Significant Accounting Policies - Estimated Useful Lives of Assets (Details)	12 Months Ended
	Dec. 31, 2015
Buildings And Land Improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life of asset (in years)	5 years
Buildings And Land Improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life of asset (in years)	40 years
Machinery and Equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life of asset (in years)	3 years
Machinery and Equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life of asset (in years)	25 years
Trucks and Automobiles | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life of asset (in years)	3 years
Trucks and Automobiles | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life of asset (in years)	10 years
Furniture and Fixtures | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life of asset (in years)	3 years
Furniture and Fixtures | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life of asset (in years)	20 years
Computers and Hardware | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life of asset (in years)	3 years
Computers and Hardware | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life of asset (in years)	10 years
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Estimated useful life of asset, description	Period of the lease or useful life, if shorter

Acquisitions and Dispositions (

Acquisitions and Dispositions (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	Apr. 01, 2015	Apr. 28, 2014	Oct. 25, 2013	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2013
Business Acquisition [Line Items]
Goodwill				$ 546.8	$ 544	$ 526.8
Adjustments related to purchase accounting				7.8
Boise Inc.
Business Acquisition [Line Items]
Business acquisition, cost of acquired entity			$ 2,100
Outstanding stock and voting equity interests acquired			100.00%
Outstanding common stock acquired, price per share			$ 12.55
Business acquisition, cost of acquired entity, cash paid			$ 1,200
Cash acquired from acquisition			121.7
Business acquisition, debt assumed			$ 829.8
Adjustments related to purchase accounting				6.4
Packaging
Business Acquisition [Line Items]
Goodwill				491.6	488.8	$ 472.9
Adjustments related to purchase accounting				$ 6.5
Packaging | Crockett Packaging
Business Acquisition [Line Items]
Business acquisition, cost of acquired entity		$ 21.2
Working capital adjustments		$ 0.7
Goodwill					$ 12.2
Hexacomb Europe and Mexico [Member] | Packaging
Business Acquisition [Line Items]
Proceeds from Divestiture of Businesses, Net of Cash Divested	$ 23

Earnings Per Share - Computatio

Earnings Per Share - Computation of Basic and Diluted Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ 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
Numerator:
Net income	$ 104.3	[1]	$ 127.8	[2]	$ 114	[3]	$ 90.8	[4]	$ 98.5	$ 104.4	[5]	$ 99.6	[6]	$ 90.1	[7]	$ 436.8	$ 392.6	$ 441.3
Less: distributed and undistributed earnings allocated to participating securities																(5.2)	(5.7)	0
Net income attributable to common shareholders																$ 431.6	$ 386.9	$ 441.3
Denominator:
Weighted average basic common shares outstanding																96.6	97	96.6
Effect of dilutive securities																0.1	0.1	0.9
Diluted common shares outstanding																96.7	97.1	97.5
Basic income per common share	$ 1.07		$ 1.31		$ 1.16		$ 0.92		$ 1	$ 1.06		$ 1.01		$ 0.92		$ 4.47	$ 3.99	$ 4.57
Diluted income per common share	$ 1.07	[1]	$ 1.31	[2]	$ 1.16	[3]	$ 0.92	[4]	$ 1	$ 1.06	[5]	$ 1.01	[6]	$ 0.92	[7]	$ 4.47	$ 3.99	$ 4.52
[1]	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).
[2]	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).
[3]	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.
[4]	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.
[5]	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).
[6]	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).
[7]	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).

Other Expense, Net - Components

Other Expense, Net - Components Expense, Net (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset disposals and write-offs		$ (14)		$ (10.1)		$ (13.2)
Integration-related and other costs	[1]	(12.9)		(20)		(17.4)
DeRidder restructuring		7.1	[2],[3]	(7.3)	[2]	0
Refundable state tax credit		3.6	[2],[4]	0		0
Class action lawsuit settlement		0		(17.6)	[5]	0
Acquisition-related costs		0		0		(17.2)	[6]
Pension curtailment charges		0		0		(10.9)	[7]
Other		2.8		(2.3)		(0.3)
Total		(6.7)		(57.3)		(59)
Mill at St. Helens, Oregon [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (Loss) on Disposition of Assets		$ 6.7	[3]	$ 0		$ 0
[1]	Includes Boise acquisition integration-related and other costs, which primarily relate to severance, retention, travel, and professional fees.
[2]	2015 and 2014 include amounts from restructuring activities at our mill in DeRidder, Louisiana including costs related to the conversion of the No. 3 newsprint machine to containerboard, our exit from the newsprint business, and other improvements. We completed the restructuring activities in first quarter 2015. In 2015, we recorded $7.1 million of income from vendor settlements.
[3]	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.
[4]	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, which was recorded as a benefit.
[5]	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.
[6]	Includes $17.2 million of acquisition-related costs, primarily for professional fees related to transaction-advisory services and expenses related to financing the acquisition of Boise.
[7]	Includes $10.9 million of non-cash pension curtailment charges related to pension plan changes in which certain hourly corrugated plant and containerboard mill employees will transition from a defined benefit pension plan to a defined contribution (401k) plan.

Income Taxes - Components of Co

Income Taxes - Components of Consolidated Income Tax Provision (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current income tax provision (benefit) -
U.S. Federal	$ 205.1	$ 185.1	$ 129.6
State and local	20.5	33.1	12.7
Foreign	0.4	0.9	0.3
Total current provision for taxes	226	219.1	142.6
Deferred -
U.S. Federal	(3.8)	(5)	(160.5)
State and local	5.6	7.6	0.3
Foreign	(0.1)	0	(0.1)
Total deferred provision (benefit) for taxes	1.7	2.6	(160.3)
Total provision (benefit) for taxes	$ 227.7	$ 221.7	$ (17.7)

Income Taxes - Summary of Effec

Income Taxes - Summary of Effective Tax Rate (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Provision computed at U.S. Federal statutory rate of 35%	$ 232.6	$ 215	$ 148.3
Alternative fuel mixture and cellulosic biofuel producer credits	0	0	(166)
State and local taxes, net of federal benefit	20	20.5	13.6
Domestic manufacturers deduction	(19.9)	(16.5)	(11.7)
Other	(5)	2.7	(1.9)
Total provision (benefit) for taxes	$ 227.7	$ 221.7	$ (17.7)
U.S. Federal statutory rate	35.00%

Income Taxes - Summary of Opera

Income Taxes - Summary of Operating Loss Carryforwards (Details) $ in Millions	Dec. 31, 2015USD ($)
Operating Loss Carryforwards [Line Items]
U.S. federal and non-U.S. NOLs	$ 70.9
State taxing jurisdiction NOLs	2.3
U.S. federal, non-U.S., and state tax credit carryforwards	0.1
U.S. federal capital loss carryforwards	5.1
Total	78.4
2016 through 2025
Operating Loss Carryforwards [Line Items]
U.S. federal and non-U.S. NOLs	0
State taxing jurisdiction NOLs	1.6
U.S. federal, non-U.S., and state tax credit carryforwards	0
U.S. federal capital loss carryforwards	5.1
Total	6.7
2026 Through 2035
Operating Loss Carryforwards [Line Items]
U.S. federal and non-U.S. NOLs	70.9
State taxing jurisdiction NOLs	0.7
U.S. federal, non-U.S., and state tax credit carryforwards	0.1
U.S. federal capital loss carryforwards	0
Total	71.7
Indefinite
Operating Loss Carryforwards [Line Items]
U.S. federal and non-U.S. NOLs	0
State taxing jurisdiction NOLs	0
U.S. federal, non-U.S., and state tax credit carryforwards	0
U.S. federal capital loss carryforwards	0
Total	$ 0

Income Taxes - Deferred Income

Income Taxes - Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Accrued liabilities		$ 18.3	$ 19
Employee benefits and compensation		32.5	44.2
Inventories		3.9	0
Net operating loss carryforwards		73.2	85.2
Stock options and restricted stock		10.7	8.9
Pension and postretirement benefits		148.2	139.1
Derivatives		13.7	16
Capital loss, general business, foreign, and AMT credit carryforwards		5.2	1.8
Gross deferred tax assets		305.7	314.2
Valuation allowance	[1]	(5.1)	(1.7)
Net deferred tax assets		300.6	312.5
Deferred tax liabilities:
Property, plant, and equipment		(545.8)	(531.6)
Goodwill and intangible assets		(101.8)	(107.7)
Inventories		0	(7.4)
Total deferred tax liabilities		(647.6)	(646.7)
Net deferred tax liabilities	[2]	(347)	(334.2)
Net Operating Loss Carryforwards
Deferred tax assets:
Valuation allowance			(1.1)
Capital Loss Carryforward
Deferred tax assets:
Valuation allowance		$ (5.1)	$ (0.6)
[1]	Deferred tax assets are reduced by a valuation allowance when it is more likely than not that some portion of the deferred tax assets will not be realized. The 2015 valuation allowance relates to capital losses. In 2014, of the $1.7 million valuation allowance, $1.1 million relates to foreign net operating loss carryforwards and credits and $0.6 million relates to capital losses. We do not expect to generate capital gains before the capital losses expire. If or when recognized, the tax benefits relating to the reversal of any of or all of the valuation allowance would be recognized as a benefit to income tax expense.
[2]	As of December 31, 2015, we did not recognize U.S. deferred income taxes on our cumulative total of undistributed foreign earnings for our non-U.S. subsidiaries. We indefinitely reinvest our earnings in operations outside the United States. It is not practicable to determine the amount of unrecognized deferred tax liability on these undistributed earnings because the actual tax liability, if any, is dependent on circumstances existing when the repatriation occurs.

Income Taxes - Summary of Unrec

Income Taxes - Summary of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance as of January 1		$ (4.4)	$ (5.4)	$ (111.3)
Increases related to current year tax positions		(0.4)	(0.3)	(1.5)
Increases related to prior years' tax positions		(2.8)	(1)	(0.1)
Decreases related to prior year's tax positions		0	0.9	64.8	[1]
Settlements with taxing authorities		0.7	0.5	106.2	[1]
Expiration of the statute of limitations		1.1	0.9	1.7
Balance at December 31		(5.8)	(4.4)	(5.4)
Unrecognized tax benefits that would impact of effective tax rate		4.2
Alternative Fuel Mixture Credit
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Settlements with taxing authorities	[1]	104.7
Boise Inc. | Alternative Fuel Mixture Credit
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Increases related to current year tax positions		0	$ 0	$ (65.2)	[2]
Decreases related to prior year's tax positions		$ 64.3
[1]	The 2013 amount includes a $104.7 million gross decrease related to the conclusion of the Internal Revenue Service audit of PCA’s alternative energy tax credits. For further discussion regarding these credits, see Note 7, Alternative Energy Tax Credits.
[2]	In 2013, PCA acquired $65.2 million of gross unrecognized tax benefits from Boise Inc. that related primarily to the taxability of the alternative energy tax credits.

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions	$ 0.4	$ 0.3	$ 1.5
Cash payments for income taxes	$ 238.3	189.5	90.7
Federal
Income tax examination (description)	A federal examination of the tax years 2010 - 2012 was concluded in February 2015.
Foreign
Open tax year	2,008
Minimum | Federal
Open tax year	2,014
Minimum | State
Open tax year	2,011
Minimum | Boise Inc.
Open tax year	2,008
Maximum | Federal
Open tax year	2,015
Maximum | State
Open tax year	2,015
Maximum | Boise Inc.
Open tax year	2,013
Alternative Fuel Mixture Credit | Boise Inc.
Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions	$ 0	$ 0	$ 65.2	[1]
[1]	In 2013, PCA acquired $65.2 million of gross unrecognized tax benefits from Boise Inc. that related primarily to the taxability of the alternative energy tax credits.

Alternative Energy Tax Credits

Alternative Energy Tax Credits - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2009
Alternative Energy Tax Credits [Line Items]
(Provision) benefit for income taxes	$ (227,700,000)	$ (221,700,000)	$ 17,700,000
Cellulosic Biofuel Tax Credits
Alternative Energy Tax Credits [Line Items]
Refundable tax credit per gallon				$ 1.01
(Provision) benefit for income taxes			103,900,000
Alternative Energy Tax Credits
Alternative Energy Tax Credits [Line Items]
Refundable tax credit per gallon				$ 0.50
(Provision) benefit for income taxes			166,000,000
Tax Related to Cellulosic Biofuel Tax Credits
Alternative Energy Tax Credits [Line Items]
(Provision) benefit for income taxes			102,000,000
Accrued Interest Related to Cellulosic Biofuel Tax Credits
Alternative Energy Tax Credits [Line Items]
(Provision) benefit for income taxes			1,900,000
Boise Inc. | Alternative Energy Tax Credits
Alternative Energy Tax Credits [Line Items]
(Provision) benefit for income taxes			$ 62,100,000

Goodwill and Intangible Asset61

Goodwill and Intangible Assets - Changes in Carrying Amount of Goodwill (Details) - USD ($) $ in Millions	Apr. 28, 2014	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Line Items]
Goodwill		$ 546.8	$ 526.8
Goodwill [Roll Forward]
Beginning Balance		546.8	526.8
Acquisitions			12.2
Adjustments related to purchase accounting			7.8
Sale of Hexacomb Europe and Mexico		(2.8)
Ending Balance		544	546.8
Packaging
Goodwill [Line Items]
Goodwill		491.6	472.9
Goodwill [Roll Forward]
Beginning Balance		491.6	472.9
Acquisitions			12.2
Adjustments related to purchase accounting			6.5
Sale of Hexacomb Europe and Mexico		(2.8)
Ending Balance		488.8	491.6
Paper
Goodwill [Line Items]
Goodwill		55.2	53.9
Goodwill [Roll Forward]
Beginning Balance		55.2	53.9
Acquisitions			0
Adjustments related to purchase accounting			1.3
Sale of Hexacomb Europe and Mexico		0
Ending Balance		55.2	$ 55.2
Crockett Packaging | Packaging
Goodwill [Line Items]
Goodwill		12.2
Goodwill [Roll Forward]
Ending Balance		12.2
Business acquisition, cost of acquired entity	$ 21.2
Working capital adjustments	$ 0.7
Hexacomb Europe and Mexico [Member]
Goodwill [Roll Forward]
Proceeds from Sale of Productive Assets		$ 23

Goodwill and Intangible Asset62

Goodwill and Intangible Assets - Components of Other Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life (in Years)	13 years 2 months 40 days	14 years 2 months 8 days
Gross Carrying Amount	$ 333.5	$ 333.5
Accumulated Amortization	62.7	40
Intangible asset amortization expense	22.7	$ 22.6	$ 6.4
Estimated Future Intangible Amortization Expense
2,016	22.5
2,017	22.4
2,018	22.2
2,019	21.3
2,020	$ 21.3
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life (in Years)	13 years 4 months	14 years 3 months
Gross Carrying Amount	$ 311.5	$ 311.5
Accumulated Amortization	$ 57.3	$ 36.9
Trademarks and Trade Names
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life (in Years)	12 years 5 months 33 days	13 years 4 months 28 days
Gross Carrying Amount	$ 21.8	$ 21.8
Accumulated Amortization	$ 5.2	$ 3
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life (in Years)	1 year 2 months 12 days	2 years 2 months 12 days
Gross Carrying Amount	$ 0.2	$ 0.2
Accumulated Amortization	$ 0.2	$ 0.1

Accrued Liabilities - Component

Accrued Liabilities - Components of Accrued Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Accrued Liabilities, Current [Abstract]
Compensation and benefits	$ 106.4	$ 130.8
Medical insurance and workers’ compensation	31.1	27
Franchise, property, sales and use taxes	16	17.5
Customer volume discounts and rebates	15.3	13.9
Severance, retention, and relocation	7.3	8.3
Environmental liabilities and asset retirement obligations	7.9	7.1
Other	9.5	15.4
Total	$ 193.5	$ 220

Debt - Summary of Debt (Details

Debt - Summary of Debt (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Sep. 05, 2014	Oct. 22, 2013	Jun. 26, 2012	Mar. 25, 2008
Debt Instrument [Line Items]
Long-term debt	$ 2,309,200	$ 2,355,400
Less current portion	6,500	6,500
Total long-term debt	$ 2,302,700	$ 2,348,900
Weighted-average interest rate	3.67%	3.56%
Line of Credit
Debt Instrument [Line Items]
Long-term debt	$ 0	$ 0
Stated interest rate	0.00%	0.00%
Credit facility, expiration date	Oct. 18, 2018
Five-Year Term Loan, due October 2018 | Unsecured Debt
Debt Instrument [Line Items]
Long-term debt	$ 25,000	$ 65,000
Debt instrument, maturity date	Oct. 18, 2018
Seven-Year Term Loan, due October 2020 | Unsecured Debt
Debt Instrument [Line Items]
Long-term debt	$ 637,000	643,500
Debt instrument, maturity date	Oct. 18, 2020
6.50% Senior Notes due March 2018 | Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 150,000	$ 150,000
Stated interest rate	6.50%	6.50%				6.50%
Debt instrument, maturity date	Mar. 15, 2018
3.90% Senior Notes, due June 2022 | Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 399,700	$ 399,700
Stated interest rate	3.90%	3.90%			3.90%
Debt instrument, maturity date	Jun. 15, 2022
Senior notes, discount	$ 300	$ 300
4.50% Senior Notes, due November 2023 | Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 698,500	$ 698,300
Stated interest rate	4.50%	4.50%		4.50%
Debt instrument, maturity date	Nov. 1, 2023
Senior notes, discount	$ 1,500	$ 1,700
3.65% Senior Notes, due September 2024 | Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 399,000	$ 398,900
Stated interest rate	3.65%	3.65%	3.65%
Debt instrument, maturity date	Sep. 15, 2024
Senior notes, discount	$ 1,000	$ 1,100
Current Portion of Long-term Debt
Debt Instrument [Line Items]
Stated interest rate	2.05%	1.79%
Long-term Debt, Excluding Current Portion
Debt Instrument [Line Items]
Weighted-average interest rate	3.67%	3.56%
London Interbank Offered Rate (LIBOR) | Five-Year Term Loan, due October 2018 | Unsecured Debt
Debt Instrument [Line Items]
Stated interest rate	1.80%	1.54%
London Interbank Offered Rate (LIBOR) | Seven-Year Term Loan, due October 2020 | Unsecured Debt
Debt Instrument [Line Items]
Stated interest rate	2.05%	1.79%

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($)	Sep. 05, 2014	Oct. 18, 2013	Oct. 31, 2013	Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2013		Oct. 22, 2013	Jun. 26, 2012	Mar. 25, 2008
Debt Instrument [Line Items]
Long-term debt				$ 2,309,200,000	$ 2,355,400,000
Financing costs paid				0	(3,400,000)		$ (19,400,000)
Book value of fixed rate debt				1,647,200,000
Book value of variable rate debt				662,000,000
Long-term debt, fair value				1,698,200,000
Repayment of debt			$ 953,600,000
Annual Principal Maturities for Debt [Abstract]
2,016				6,500,000
2,017				6,500,000
2,018				181,500,000
2,019				6,500,000
2,020				611,000,000
2020 and thereafter				1,500,000,000
Interest payments				85,500,000	77,000,000
Interest payments and redemption premium payments paid for debt obligations							105,700,000
Redemption Premium							54,800,000
Amortization of net (loss) gain on treasury lock				(5,700,000)	(5,700,000)		(5,700,000)
Amortization of financing costs				1,800,000	3,300,000		10,300,000
Write-off of deferred financing costs				85,500,000	88,400,000	[1]	58,300,000	[2],[3]
Boise Inc.
Debt Instrument [Line Items]
Repayment of debt			$ 829,800,000
Annual Principal Maturities for Debt [Abstract]
Amortization of financing costs							8,200,000
Line of Credit
Debt Instrument [Line Items]
Credit facility borrowing capacity		$ 350,000,000
Unused borrowing capacity				326,500,000
Long-term debt				$ 0	$ 0
Stated interest rate				0.00%	0.00%
Credit facility, expiration date				Oct. 18, 2018
Five-Year and Seven-Year Term Loans, due October 2018 and 2020, respectively | Unsecured Debt
Debt Instrument [Line Items]
Debt, face amount		1,650,000,000
Repayment of debt				$ 591,500,000
Five-Year Term Loan, due October 2018 | Unsecured Debt
Debt Instrument [Line Items]
Debt, face amount		$ 650,000,000
Applicable margin		1.375%		1.375%	1.375%
Long-term debt				$ 25,000,000	$ 65,000,000
Repayments of Debt				$ 40,000,000
Seven-Year Term Loan, due October 2020 | Unsecured Debt
Debt Instrument [Line Items]
Debt, face amount		$ 650,000,000
Applicable margin		1.625%		1.625%	1.625%
Long-term debt				$ 637,000,000	$ 643,500,000
Repayments of Debt				6,500,000
6.50% Senior Notes due March 2018 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount											$ 150,000,000
Long-term debt				$ 150,000,000	$ 150,000,000
Stated interest rate				6.50%	6.50%						6.50%
3.90% Senior Notes, due June 2022 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount										$ 400,000,000
Long-term debt				$ 399,700,000	$ 399,700,000
Stated interest rate				3.90%	3.90%					3.90%
4.50% Senior Notes, due November 2023 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount									$ 700,000,000
Long-term debt				$ 698,500,000	$ 698,300,000
Stated interest rate				4.50%	4.50%				4.50%
3.65% Senior Notes, due September 2024 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount	$ 400,000,000
Long-term debt				$ 399,000,000	$ 398,900,000
Stated interest rate	3.65%			3.65%	3.65%
Financing costs paid	$ (3,400,000)
Annual Principal Maturities for Debt [Abstract]
Amortization of financing costs					$ 1,500,000
Letter of Credit | Line of Credit
Debt Instrument [Line Items]
Outstanding letters of credit				$ 23,500,000
Receivables Credit Facility
Debt Instrument [Line Items]
Repayment of debt							$ 109,000,000
Write-Off of Deferred Financing Costs
Annual Principal Maturities for Debt [Abstract]
Write-off of deferred financing costs					$ 1,500,000
London Interbank Offered Rate (LIBOR) | Five-Year Term Loan, due October 2018 | Unsecured Debt
Debt Instrument [Line Items]
Stated interest rate				1.80%	1.54%
Annual Principal Maturities for Debt [Abstract]
Reference Interest Rate				0.42%	0.17%
London Interbank Offered Rate (LIBOR) | Seven-Year Term Loan, due October 2020 | Unsecured Debt
Debt Instrument [Line Items]
Stated interest rate				2.05%	1.79%
Annual Principal Maturities for Debt [Abstract]
Reference Interest Rate				0.42%	0.17%
[1]	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.
[2]	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.
[3]	On October 25, 2013, we acquired Boise Inc. (Boise). Our financial results include Boise subsequent to acquisition.

Employee Benefit Plans and Ot66

Employee Benefit Plans and Other Postretirement Benefits - Additional Information (Detail) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Company contributions		$ 0.4	$ 30
Deferred compensation liability	$ 12.8	$ 12.4
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year	$ 27
Employee Stock Ownership Plan
Defined Benefit Plan Disclosure [Line Items]
Company's common stock	3.1	2.2
Minimum
Defined Benefit Plan Disclosure [Line Items]
Company's contribution to pension plan, percentage	3.00%
Maximum
Defined Benefit Plan Disclosure [Line Items]
Company's contribution to pension plan, percentage	5.00%
Scenario, Forecast
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Effect of Plan Amendment on Net Periodic Benefit Cost				$ 8
Matching Contributions
Defined Benefit Plan Disclosure [Line Items]
Company's contribution to defined contribution plans	$ 37.9	$ 28.3	15
Service Related Contributions
Defined Benefit Plan Disclosure [Line Items]
Company's contribution to defined contribution plans	$ 12.4	7.4	$ 5.3
Postretirement Plans
Defined Benefit Plan Disclosure [Line Items]
Minimum service period for medical benefit plan coverage, years	10
Minimum retirement age for medical benefit plan coverage, years	58
Employee age after which minimum service period to be completed for medical benefit plan coverage, years	48
Company contributions	$ 2	$ 1.3

Employee Benefit Plans and Ot67

Employee Benefit Plans and Other Postretirement Plans - Change in Benefit Obligations and Change in Fair Value of Plan Assets Related to Pension and Postretirement Plans (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value at beginning of period		$ 805.9
Company contributions			$ 0.4	$ 30
Fair value of plan assets at plan year end		764.4	805.9
Amounts Recognized on Consolidated Balance Sheets
Noncurrent liabilities		(358.6)	$ (361.7)
Amounts Recognized in Accumulated Other Comprehensive (Income) Loss (Pre-Tax)
Accumulated benefit obligation for plans with obligations in excess of plan assets		$ 1,050
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Weighted-Average Assumptions Used to Determine Benefit Obligation, Discount Rate		4.51%	4.14%	5.00%
Change in Benefit Obligations [Roll Forward]
Benefit obligation at beginning of period		$ 1,129.6	$ 929.8
Service cost		24	22.7	$ 24.5
Interest cost		46.2	45.9	21.5
Plan amendments		3	2.6
Actuarial (gain) loss	[1]	(75.7)	159.2
Special termination benefits		0	0.3	0
Participant contributions		0	0
Benefits paid		(34.6)	(30.9)
Benefit obligation at plan year end		1,092.5	1,129.6	929.8
Accumulated benefit obligation portion of above		1,048.5	1,078.6
Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value at beginning of period		805.9	772.1
Actual return on plan assets		(8.1)	63.4
Company contributions		1.2	1.3
Participant contributions		0	0
Benefits paid		(34.6)	(30.9)
Fair value of plan assets at plan year end		764.4	805.9	$ 772.1
Underfunded status		(328.1)	(323.7)
Amounts Recognized on Consolidated Balance Sheets
Current liabilities		(0.9)	(1.1)
Noncurrent liabilities		(327.2)	(322.6)
Accrued obligation recognized at December 31		(328.1)	(323.7)
Amounts Recognized in Accumulated Other Comprehensive (Income) Loss (Pre-Tax)
Amounts Recognized in Accumulated Other Comprehensive (Income) Loss (Pre-Tax)		25.1	27.6
Actuarial loss		149.4	172.6
Total		$ 174.5	$ 200.2
Postretirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Weighted-Average Assumptions Used to Determine Benefit Obligation, Discount Rate		4.35%	3.95%	4.85%
Change in Benefit Obligations [Roll Forward]
Benefit obligation at beginning of period		$ 31.9	$ 26.3
Service cost		1.7	1.6	$ 2.1
Interest cost		1.2	1.2	1.3
Plan amendments		0	0
Actuarial (gain) loss		(11.4)	4.1
Special termination benefits		0	0	0
Participant contributions		1.2	1.2
Benefits paid		(3.2)	(2.5)
Benefit obligation at plan year end		21.4	31.9	26.3
Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value at beginning of period		0	0
Actual return on plan assets		0	0
Company contributions		2	1.3
Participant contributions		1.2	1.2
Benefits paid		(3.2)	(2.5)
Fair value of plan assets at plan year end		0	0	$ 0
Underfunded status		(21.4)	(31.9)
Amounts Recognized on Consolidated Balance Sheets
Current liabilities		(1.1)	(1.4)
Noncurrent liabilities		(20.3)	(30.5)
Accrued obligation recognized at December 31		(21.4)	(31.9)
Amounts Recognized in Accumulated Other Comprehensive (Income) Loss (Pre-Tax)
Amounts Recognized in Accumulated Other Comprehensive (Income) Loss (Pre-Tax)		0.2	0.3
Actuarial loss		(6)	5.5
Total		$ (5.8)	$ 5.8
[1]	In 2015, the increase in the weighted average discount rate used to estimate our pension benefit obligations and changes in mortality assumptions from the Society of Actuaries resulted in an actuarial gain. The actuarial loss in 2014 was due primarily to a decrease in the weighted average discount rate and updated mortality assumptions.

Employee Benefit Plans and Ot68

Employee Benefit Plans and Other Postretirement Plans - Components of Net Periodic Benefit Cost and Other Comprehensive (Income) Loss (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Company contributions			$ 0.4	$ 30
Components of net periodic benefit cost
Net amortization of unrecognized amounts, Curtailment loss		$ 0	0	10.9	[1]
Estimated Net Periodic Benefit Cost and Amortization of Other Comprehensive Income for The Next Year
Estimated net periodic benefit cost for 2016		10.5
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Company contributions		1.2	1.3
Components of net periodic benefit cost
Service cost		24	22.7	24.5
Interest cost		46.2	45.9	21.5
Expected return on plan assets		(53.1)	(50.7)	(21.4)
Special termination benefits		0	0.3	0
Net amortization of unrecognized amounts, Prior service cost		5.5	6.5	6.2
Net amortization of unrecognized amounts, Actuarial loss		8.7	0.6	4.7
Net amortization of unrecognized amounts, Curtailment loss		0	0	10.9	[2]
Net periodic benefit cost		31.3	25.3	46.4
Changes in plan assets and benefit obligations recognized in other comprehensive (income) loss
Actuarial net (gain) loss		(14.5)	146.4	(58.7)
Prior service cost		3	2.6	13.8
Amortization of prior service cost		(5.5)	(6.5)	(6.2)
Amortization of actuarial loss		(8.7)	(0.6)	(4.7)
Curtailment loss		0	0	(10.9)	[2]
Total recognized in other comprehensive (income) loss (b)	[3]	(25.7)	141.9	(66.7)
Total recognized in net periodic benefit cost and other comprehensive (income) loss - pretax		5.6	167.2	(20.3)
Postretirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Company contributions		2	1.3
Components of net periodic benefit cost
Service cost		1.7	1.6	2.1
Interest cost		1.2	1.2	1.3
Expected return on plan assets		0	0	0
Special termination benefits		0	0	0
Net amortization of unrecognized amounts, Prior service cost		0.1	(0.2)	(0.4)
Net amortization of unrecognized amounts, Actuarial loss		0.1	0.1	0.5
Net amortization of unrecognized amounts, Curtailment loss		0	0	0
Net periodic benefit cost		3.1	2.7	3.5
Changes in plan assets and benefit obligations recognized in other comprehensive (income) loss
Actuarial net (gain) loss		(11.4)	4.2	(7.8)
Prior service cost		0	0	0
Amortization of prior service cost		(0.1)	0.2	0.4
Amortization of actuarial loss		(0.1)	(0.1)	(0.5)
Curtailment loss		0	0	0
Total recognized in other comprehensive (income) loss (b)	[3]	(11.6)	4.3	(7.9)
Total recognized in net periodic benefit cost and other comprehensive (income) loss - pretax		$ (8.5)	$ 7	$ (4.4)
[1]	Includes $10.9 million of non-cash pension curtailment charges related to pension plan changes in which certain hourly corrugated plant and containerboard mill employees will transition from a defined benefit pension plan to a defined contribution (401k) plan.
[2]	In 2013, we recognized curtailment losses in "Other expense, net" in the Consolidated Statements of Income for recent USW negotiations, resulting in the bifurcation of the active USW population between those grandfathered in the current formula (with continued accruals) and non-grandfathered in the current formula (frozen benefits at the contract date).
[3]	Accumulated losses in excess of 10% of the greater of the projected benefit obligation or the market-related value of assets will be recognized on a straight-line basis over the average remaining service period of active employees, which is between seven to ten years, to the extent that losses are not offset by gains in subsequent years. The estimated net loss and prior service cost that will be amortized from "Accumulated other comprehensive loss" into pension expense in 2016 is $10.5 million.

Employee Benefit Plans and Ot69

Employee Benefit Plans and Other Postretirement Plans - Schedule of Weighted-Average Assumptions Used to Determine Benefit Obligations and Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Company contributions			$ 0.4	$ 30
Scenario, Forecast
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost, Expected return on plan assets	6.57%
Weighted-Average expected return on plan assets for 2016	6.57%
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Company contributions		$ 1.2	$ 1.3
Weighted-Average Assumptions Used to Determine Benefit Obligation, Discount Rate		4.51%	4.14%	5.00%
Weighted-Average Assumptions Used to Determine Benefit Obligations, Rate of compensation increase		4.00%	4.00%	4.00%
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost, Discount rate		4.14%	5.00%	4.57%
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost, Expected return on plan assets		6.73%	6.69%	6.53%
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost, Rate of compensation increase		4.00%	4.00%	4.00%
Discount rate to calculate net periodic benefit cost for 2016		4.14%	5.00%	4.57%
Weighted-Average expected return on plan assets for 2016		6.73%	6.69%	6.53%
Postretirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Company contributions		$ 2	$ 1.3
Weighted-Average Assumptions Used to Determine Benefit Obligation, Discount Rate		4.35%	3.95%	4.85%
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost, Discount rate		3.95%	4.85%	4.00%
Discount rate to calculate net periodic benefit cost for 2016		3.95%	4.85%	4.00%

Employee Benefit Plans and Ot70

Employee Benefit Plans and Other Postretirement Plans - Schedule of Assumed Health Care Cost Trend Rates for Postretirement Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Company contributions		$ 0.4	$ 30
Postretirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Company contributions	$ 2	$ 1.3
Health care cost trend rate assumed for next year	7.60%	7.75%	7.75%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	4.50%	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2,024	2,023	2,020

Employee Benefit Plans and Ot71

Employee Benefit Plans and Other Postretirement Plans - Schedule of Effects of One-Percentage Point Change in Assumed Health Care Cost Trends on Postretirement Benefits (Details) - Postretirement Plans $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Effect on postretirement benefit obligation, 1-Percentage Point Increase	$ 0.8
Effect on net postretirement benefit cost, 1-Percentage Point Increase	0
Effect on postretirement benefit obligation, 1-Percentage Point Decrease	(0.7)
Effect on net postretirement benefit cost, 1-Percentage Point Decrease	$ (0.1)

Employee Benefit Plans and Ot72

Employee Benefit Plans and Other Postretirement Plans - Schedule of Pension Plan Asset Investments and Target Allocations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Company contributions		$ 0.4	$ 30
Fair value of plan assets	$ 764.4	$ 805.9
Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Fair Value	55.00%	54.00%
International Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Fair Value	22.00%	23.00%
U.S. Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Fair Value	20.00%	20.00%
Real Estate Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Fair Value	1.00%	1.00%
Other Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Fair Value	2.00%	2.00%
Packaging Corporation of America
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 275.2
Packaging Corporation of America | Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocations	58.00%
Packaging Corporation of America | Other Securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocations	3.00%
Packaging Corporation of America | Equities
Defined Benefit Plan Disclosure [Line Items]
Target Allocations	39.00%
Boise Inc.
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 489.2
Boise Inc. | Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocations	55.00%
Boise Inc. | Equities
Defined Benefit Plan Disclosure [Line Items]
Target Allocations	45.00%

Employee Benefit Plans and Ot73

Employee Benefit Plans and Other Postretirement Plans - Fair Value Measurements of Plan Assets (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Company contributions			$ 0.4	$ 30
Fair value of plan assets		$ 805.9	805.9		$ 764.4
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period		805.9
Fair value of plan assets at plan year end		764.4	805.9
Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		8.1	8.1		6.4
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period		8.1
Sales		(1.8)
Unrealized gain		0.1
Fair value of plan assets at plan year end		6.4	8.1
Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[1]	1.8	1.8		4.1
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[1]	1.8
Fair value of plan assets at plan year end	[1]	4.1	1.8
Short-term Investments | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[1]	0	0		0
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[1]	0
Fair value of plan assets at plan year end	[1]	0	0
Short-term Investments | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[1]	1.8	1.8		4.1
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[1]	1.8
Fair value of plan assets at plan year end	[1]	4.1	1.8
Short-term Investments | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[1]	0	0		0
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[1]	0
Fair value of plan assets at plan year end	[1]	0	0
Domestic equities (Mutual Funds)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	38.2	38.2		47.1
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[2]	38.2
Fair value of plan assets at plan year end	[2]	47.1	38.2
Domestic equities (Mutual Funds) | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	38.2	38.2		47.1
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[2]	38.2
Fair value of plan assets at plan year end	[2]	47.1	38.2
Domestic equities (Mutual Funds) | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	0	0		0
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[2]	0
Fair value of plan assets at plan year end	[2]	0	0
Domestic equities (Mutual Funds) | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	0	0		0
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[2]	0
Fair value of plan assets at plan year end	[2]	0	0
International equities (Mutual Funds)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	49.9	49.9		50.7
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[2]	49.9
Fair value of plan assets at plan year end	[2]	50.7	49.9
International equities (Mutual Funds) | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	49.9	49.9		50.7
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[2]	49.9
Fair value of plan assets at plan year end	[2]	50.7	49.9
International equities (Mutual Funds) | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	0	0		0
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[2]	0
Fair value of plan assets at plan year end	[2]	0	0
International equities (Mutual Funds) | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	0	0		0
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[2]	0
Fair value of plan assets at plan year end	[2]	0	0
Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	8.9	8.9		8.5
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[2]	8.9
Fair value of plan assets at plan year end	[2]	8.5	8.9
Real Estate | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	8.9	8.9		8.5
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[2]	8.9
Fair value of plan assets at plan year end	[2]	8.5	8.9
Real Estate | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	0	0		0
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[2]	0
Fair value of plan assets at plan year end	[2]	0	0
Real Estate | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	0	0		0
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[2]	0
Fair value of plan assets at plan year end	[2]	0	0
Fixed Income (Mutual Funds)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	178.2	178.2		156.5
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[2]	178.2
Fair value of plan assets at plan year end	[2]	156.5	178.2
Fixed Income (Mutual Funds) | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	178.2	178.2		156.5
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[2]	178.2
Fair value of plan assets at plan year end	[2]	156.5	178.2
Fixed Income (Mutual Funds) | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	0	0		0
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[2]	0
Fair value of plan assets at plan year end	[2]	0	0
Fixed Income (Mutual Funds) | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	0	0		0
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[2]	0
Fair value of plan assets at plan year end	[2]	0	0
Domestic equities (Common/collective trusts)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[1]	122.3	122.3		104.4
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[1]	122.3
Fair value of plan assets at plan year end	[1]	104.4	122.3
Domestic equities (Common/collective trusts) | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[1]	0	0		0
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[1]	0
Fair value of plan assets at plan year end	[1]	0	0
Domestic equities (Common/collective trusts) | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[1]	122.3	122.3		104.4
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[1]	122.3
Fair value of plan assets at plan year end	[1]	104.4	122.3
Domestic equities (Common/collective trusts) | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[1]	0	0		0
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[1]	0
Fair value of plan assets at plan year end	[1]	0	0
International equities (Common/Collective Trust Funds)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[1]	137.8	137.8		121.6
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[1]	137.8
Fair value of plan assets at plan year end	[1]	121.6	137.8
International equities (Common/Collective Trust Funds) | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[1]	0	0		0
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[1]	0
Fair value of plan assets at plan year end	[1]	0	0
International equities (Common/Collective Trust Funds) | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[1]	137.8	137.8		121.6
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[1]	137.8
Fair value of plan assets at plan year end	[1]	121.6	137.8
International equities (Common/Collective Trust Funds) | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[1]	0	0		0
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[1]	0
Fair value of plan assets at plan year end	[1]	0	0
Fixed Income (Common/Collective Trust Funds) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[1]	259.3	259.3		263
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[1]	259.3
Fair value of plan assets at plan year end	[1]	263	259.3
Fixed Income (Common/Collective Trust Funds) [Member] | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[1]	0	0		0
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[1]	0
Fair value of plan assets at plan year end	[1]	0	0
Fixed Income (Common/Collective Trust Funds) [Member] | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[1]	259.3	259.3		263
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[1]	259.3
Fair value of plan assets at plan year end	[1]	263	259.3
Fixed Income (Common/Collective Trust Funds) [Member] | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[1]	0	0		0
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[1]	0
Fair value of plan assets at plan year end	[1]	0	0
Private Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[3]	8.1	8.1		6.4
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[3]	8.1
Fair value of plan assets at plan year end	[3]	6.4	8.1
Private Equity Securities | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[3]	0	0		0
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[3]	0
Fair value of plan assets at plan year end	[3]	0	0
Private Equity Securities | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[3]	0	0		0
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[3]	0
Fair value of plan assets at plan year end	[3]	0	0
Private Equity Securities | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[3]	8.1	8.1		6.4
Investment commitment					15
Unfunded portion of investment commitment					5
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	[3]	8.1
Fair value of plan assets at plan year end	[3]	6.4	8.1
Total Securities at Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		804.5	804.5		762.3
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period		804.5
Fair value of plan assets at plan year end		762.3	804.5
Total Securities at Fair Value | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		275.2	275.2		262.8
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period		275.2
Fair value of plan assets at plan year end		262.8	275.2
Total Securities at Fair Value | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		521.2	521.2		493.1
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period		521.2
Fair value of plan assets at plan year end		493.1	521.2
Total Securities at Fair Value | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		8.1	8.1		6.4
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period		8.1
Fair value of plan assets at plan year end		6.4	8.1
Receivables and Accruals, Net [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		1.4	1.4		$ 2.1
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period		1.4
Fair value of plan assets at plan year end		$ 2.1	$ 1.4
[1]	Investments in common/collective trust funds valued using net asset values (NAV) provided by the administrator of the funds. We use NAV as a practical expedient to fair value. The NAV is based on the value of the underlying assets owned by the fund, minus its liabilities, and then divided by the number of units outstanding. While the underlying assets are actively traded on an exchange, the funds are not. There are currently no redemption restrictions on these investments. There are certain funds with one-day redeemable notice.
[2]	Investments in mutual funds valued at quoted market values on the last business day of the fiscal year.
[3]	Investments in this category are invested in the Pantheon Global Secondary Fund IV, LP. The fund specializes in investments in the private equity secondary market and occasionally directly in private companies to maximize capital growth. Fund investments are carried at fair value as determined quarterly using the market approach to estimate the fair value of private investments. The market approach utilizes prices and other relevant information generated by market transactions, type of security, size of the position, degree of liquidity, restrictions on the disposition, latest round of financing data, current financial position, and operating results, among other factors. In circumstances where fair values are not provided with respect to any of the company's fund investments, the investment advisor will seek to determine the fair value of such investments based on information provided by the general partners or managers of such funds or from other sources. Audited financial statements are provided by fund management annually. Notwithstanding the above, the variety of valuation bases adopted and quality of management data of the ultimate underlying investee companies means that there are inherent difficulties in determining the value of the investments. Amounts realized on the sale of these investments may differ from the calculated values. Boise had originally committed to a $15.0 million investment, with $5.0 million of the commitment unfunded at December 31, 2015.

Employee Benefit Plans and Ot74

Employee Benefit Plans and Other Postretirement Plans - Schedule of Estimated Benefit Payments (Details) $ in Millions	Dec. 31, 2015USD ($)
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
2,016	$ 37.8
2,017	40.9
2,018	44.8
2,019	48.6
2,020	52.4
2021 - 2025	312.7
Postretirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
2,016	1.1
2,017	1.1
2,018	1.3
2,019	1.3
2,020	1.5
2021 - 2025	$ 7.9

Asset Retirement Obligations -

Asset Retirement Obligations - Changes to Asset Retirement Obligation (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligation at beginning of period		$ 37	$ 32
Sale of St. Helens		(11.2)	0
Accretion expense		2.1	1
Payments		(1.6)	(0.1)
Revisions in estimated cash flows		0.2	0
Liabilities incurred		(0.3)	0
Acquisition		0	4.1
Asset retirement obligation at end of period		26.2	37	$ 32
Gain on sale		$ (0.5)	$ (7)	$ (9.4)
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Sale of St. Helens	$ (11.2)

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized under plan	10,600,000
Long-term equity incentive plan, termination date	May 1, 2023
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,600,000
Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards vested | $	$ 0.3
Stock Issued During Period, Shares, Restricted Stock Award, Gross	5,090
Common Stock Dividends, Shares	174

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Restricted Stock and Performance Units Activity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Restricted Stock
Restricted Stock and Performance Unit Activity [Roll Forward]
Outstanding at January 1	1,184,299	1,463,694	1,771,664
Granted	218,957	229,489	331,053
Vested	(389,481)	(507,222)	(605,458)
Forfeitures	(5,981)	(1,662)	(33,565)
Outstanding at December 31	1,007,794	1,184,299	1,463,694
Restricted Stock and Performance Unit Activity (Weighted Average Grant-date Fair Value) [Abstract]
Weighted average grant-date fair value, Outstanding at January 1	$ 41.71	$ 31.48	$ 23.44
Weighted average grant-date fair value, Granted	65.16	70.24	51.99
Weighted average grant-date fair value, Vested	32.77	26.29	19.54
Weighted average grant-date fair value, Forfeitures	66.42	61.05	24.76
Weighted average grant-date fair value, Outstanding at December 31	$ 49.47	$ 41.71	$ 31.48
Fair value of awards vested	$ 26.3	$ 36.4	$ 29.5
Performance Units
Restricted Stock and Performance Unit Activity [Roll Forward]
Outstanding at January 1	127,489	70,600
Granted	53,102	56,889	70,600
Vested	(4,916)	0
Forfeitures	0	0
Outstanding at December 31	175,675	127,489	70,600
Restricted Stock and Performance Unit Activity (Weighted Average Grant-date Fair Value) [Abstract]
Weighted average grant-date fair value, Outstanding at January 1	$ 58.25	$ 47.83
Weighted average grant-date fair value, Granted	65.04	71.19	$ 47.83
Weighted average grant-date fair value, Vested	71.19	0
Weighted average grant-date fair value, Forfeitures	0	0
Weighted average grant-date fair value, Outstanding at December 31	$ 59.94	$ 58.25	$ 47.83
Fair value of awards vested	$ 0.3

Share-Based Compensation - Comp

Share-Based Compensation - Compensation Expense for Share-Based Awards (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Impact on income before income taxes	$ 18.2	$ 15.6	$ 14.8
Income tax benefit	(7.1)	(6.1)	(5.8)
Impact on net income	11.1	9.5	9
Restricted Stock
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Impact on income before income taxes	15.2	13.8	14.3
Performance Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Impact on income before income taxes	$ 3	$ 1.8	$ 0.5

Share-Based Compensation - Unre

Share-Based Compensation - Unrecognized Compensation Expense for Share-Based Awards (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 32.8
Weighted-average recognition period	2 years 7 months 6 days
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 26.6
Weighted-average recognition period	2 years 6 months
Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 6.2
Weighted-average recognition period	2 years 9 months 6 days

Derivative Instruments and He80

Derivative Instruments and Hedging Activities - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2008
Derivative [Line Items]
Net amount of settlement gains (losses) on derivative instruments included in accumulated OCI to be amortized over next 12 months, before tax	$ (5.7)
Net amount of settlement gains (losses) on derivative instruments included in accumulated OCI to be amortized over next 12 months, after tax	$ (3.5)
2008 Interest Rate Protection Agreement
Derivative [Line Items]
Payments for (Proceeds from) settlement of interest rate protection agreement				$ 4.4
2010 Interest Rate Protection Agreement
Derivative [Line Items]
Payments for (Proceeds from) settlement of interest rate protection agreement			$ (9.9)
2011 Interest Rate Protection Agreement
Derivative [Line Items]
Payments for (Proceeds from) settlement of interest rate protection agreement		$ 65.5

Derivative Instruments and He81

Derivative Instruments and Hedging Activities - Impact of Derivative Instruments on Consolidated Statements of Income and OCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	$ (5.7)	$ (5.7)	$ (5.7)
Treasury Locks, Net Of Tax
Derivative Instruments, Gain (Loss) [Line Items]
Net Gain (Loss) Recognized in Accumulated OCI (Effective Portion)	$ (21.2)	$ (24.7)

Stockholders' Equity (Details)

Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions	Jan. 15, 2016	Dec. 15, 2015	Apr. 15, 2015	Feb. 26, 2015	Dec. 09, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Common stock dividends paid						$ 200.8	$ 157.4	$ 109.1
Dividends declared per common share (US$ per share)		$ 0.55				$ 2.20	$ 1.60	$ 1.51
Common Stock, Dividends, Per Share, Cash Paid			$ 0.55
Subsequent Event
Common stock dividends paid	$ 53.1
Annual Dividend [Member]
Dividends declared per common share (US$ per share)				$ 2.20	$ 1.60

Stockholders' Equity - Share Re

Stockholders' Equity - Share Repurchase Program (Details) - USD ($)	2 Months Ended	12 Months Ended
	Feb. 26, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Feb. 25, 2016	Jul. 21, 2015
Class of Stock [Line Items]
Stock Repurchase Program, Additional Amount Authorized						$ 150,000,000
Common stock repurchase authorized amount						$ 205,000,000
Common stock repurchased and retired, shares		2,326,493	0	171,263
Common stock repurchased and retired, weighted average price per share		$ 66.50	$ 0	$ 45.54
Common stock repurchased and retired, total value		$ 154,700,000	$ 0	$ 7,800,000
Common stock repurchase authorization amount available		$ 93,400,000
Subsequent Event
Class of Stock [Line Items]
Stock Repurchase Program, Additional Amount Authorized					$ 200,000,000
Stock Repurchased During Period, Shares	1,868,487
Stock Repurchased During Period, Value	$ 93,400,000

Stockholders' Equity - Changes

Stockholders' Equity - Changes in Accumulated Other Comprehensive Income by Component (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31, 2014	$ (153.9)
Other comprehensive income (loss) before reclassifications, net of tax	12.5
Amounts reclassified from AOCI, net of tax	16.5
Other comprehensive income (loss)	29	$ (88.9)	$ 49
Balance at December 31, 2015	(124.9)	(153.9)
Net amount of settlement gains (losses) on derivative instruments included in accumulated OCI to be amortized over next 12 months, before tax	(5.7)
Net amount of settlement gains (losses) on derivative instruments included in accumulated OCI to be amortized over next 12 months, after tax	(3.5)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31, 2014	(2.7)
Other comprehensive income (loss) before reclassifications, net of tax	(1.5)
Amounts reclassified from AOCI, net of tax	4.2
Other comprehensive income (loss)	2.7
Balance at December 31, 2015	0	(2.7)
Unfunded Employee Benefit Obligations
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31, 2014	(126.1)
Other comprehensive income (loss) before reclassifications, net of tax	14
Amounts reclassified from AOCI, net of tax	8.8
Other comprehensive income (loss)	22.8
Balance at December 31, 2015	(103.3)	(126.1)
Treasury Lock | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31, 2014	(24.7)
Other comprehensive income (loss) before reclassifications, net of tax	0
Amounts reclassified from AOCI, net of tax	3.5
Other comprehensive income (loss)	3.5
Balance at December 31, 2015	(21.2)	(24.7)
Foreign Exchange Contract | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31, 2014	(0.4)
Other comprehensive income (loss) before reclassifications, net of tax	0
Amounts reclassified from AOCI, net of tax	0
Other comprehensive income (loss)	0
Balance at December 31, 2015	$ (0.4)	$ (0.4)

Stockholders' Equity - Reclassi

Stockholders' Equity - Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2015

[4]

Sep. 30, 2015

[5]

Jun. 30, 2015

[6]

Mar. 31, 2015

[7]

Dec. 31, 2014

Sep. 30, 2014

[8]

Jun. 30, 2014

[9]

Mar. 31, 2014

[10]

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]

Interest expense, net

$ (85.5)

$ (88.4)

[1]

$ (58.3)

[2],[3]

Income before taxes

664.5

614.3

423.6

[3]

(Provision) benefit for income taxes

(227.7)

(221.7)

17.7

Net income

$ 104.3

$ 127.8

$ 114

$ 90.8

$ 98.5

$ 104.4

$ 99.6

$ 90.1

436.8

392.6

$ 441.3

Unfunded Employee Benefit Obligations | Reclassification Out Of Accumulated Other Comprehensive Income

Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]

Amortization of prior service cost

(5.6)

(6.3)

Amortization of actuarial gain / (losses)

(8.8)

(0.7)

Income before taxes

(14.4)

(7)

(Provision) benefit for income taxes

5.6

2.8

Net income

(8.8)

(4.2)

Foreign Exchange Contract | Foreign Currency Translation Adjustments | Reclassification Out Of Accumulated Other Comprehensive Income

Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]

Interest expense, net

(4.2)

0

(Provision) benefit for income taxes

0

0

Net income

(4.2)

0

Treasury Lock | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges | Reclassification Out Of Accumulated Other Comprehensive Income

Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]

Interest expense, net

(5.7)

(5.7)

(Provision) benefit for income taxes

2.2

2.2

Net income

$ (3.5)

$ (3.5)

[1]

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.

[2]

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.

[3]

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

[4]

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).

[5]

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).

[6]

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.

[7]

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.

[8]

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).

[9]

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).

[10]

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).

Concentrations of Risk (Details

Concentrations of Risk (Details) employee in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)employee	Dec. 31, 2014USD ($)
Concentration Risk [Line Items]
Accounts Receivable, Net, Current	$ 636.5	$ 646.1
Number of employees of PCA | employee	13
Percentage of hourly employees represented by unions	70.00%
Workforce Subject to Collective Bargaining Arrangements
Concentration Risk [Line Items]
Concentration risk, percentage	50.00%
Workforce Subject to Collective Bargaining Arrangements Expiring within One Year
Concentration Risk [Line Items]
Concentration risk, percentage	10.00%
Office Depot | Credit Concentration Risk
Concentration Risk [Line Items]
Accounts Receivable, Net, Current	$ 39.5	$ 52.6
Office Depot | Total Company Sales Revenue | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	9.00%	9.00%
Office Depot | Total Company Receivables | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	6.00%	8.00%
Paper | Office Depot | Paper Segment Sales Revenue | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	45.00%	45.00%

Transactions With Related Par87

Transactions With Related Parties - Additional Information (Detail) - USD ($) $ in Millions	2 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Related Party Transaction [Line Items]
Carrying amount of LTP's assets		$ 4.5	$ 5.2
Carrying amount of LTP's liabilities		$ 4.5	5.2
Boise Cascade Co-Owner of LTP
Related Party Transaction [Line Items]
Variable interest entity, ownership percentage		50.00%
Boise Cascade Co-Owner of LTP | Fiber
Related Party Transaction [Line Items]
Revenue from Related Parties	$ 10.3	$ 88.8	75.8
Fiber Costs From Related Parties		$ 20.7	$ 28.7	$ 3.7
Packaging Corporation of America
Related Party Transaction [Line Items]
Variable interest entity, ownership percentage		50.00%

Segment Information - Additiona

Segment Information - Additional Information (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]

Operating Income (Loss)

$ 175.9

[1]

$ 219.4

[2]

$ 197.6

[3]

$ 157.1

[4]

$ 173.2

$ 188.4

[5]

$ 180.2

[6]

$ 160.9

[7]

$ 750

$ 702.7

$ 481.9

[8]

Number of reportable segments

3

Net sales

$ 1,390.9

$ 1,470.8

$ 1,454.3

$ 1,425.7

1,434

$ 1,518.9

$ 1,468.4

$ 1,431.3

$ 5,741.7

5,852.6

3,665.3

Paper

Segment Reporting Information [Line Items]

Operating Income (Loss)

112.5

[9]

135.4

13.5

[8],[10]

Packaging

Segment Reporting Information [Line Items]

Operating Income (Loss)

714.9

[11]

663.2

[12]

554.2

[8],[13]

Corporate and Other

Segment Reporting Information [Line Items]

Operating Income (Loss)

$ (77.4)

[14]

$ (95.9)

[15]

(85.8)

[8],[16]

Office Depot | Customer Concentration Risk | Paper Segment Sales Revenue | Paper

Segment Reporting Information [Line Items]

Concentration risk, percentage

45.00%

45.00%

Foreign operations

Segment Reporting Information [Line Items]

Net sales

$ 177.2

$ 378.8

$ 162.4

Foreign operations | Packaging

Segment Reporting Information [Line Items]

Long-Lived Assets

$ 12.4

$ 12.4

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

Other Restructuring [Member] | Packaging

Segment Reporting Information [Line Items]

Operating Income (Loss)

$ 2

[1]

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).

[2]

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).

[3]

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.

[4]

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.

[5]

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).

[6]

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).

[7]

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).

[8]

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

[9]

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.

[10]

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

[11]

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.

[12]

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.

[13]

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.

[14]

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.

[15]

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.

[16]

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

Segment Information - Segment S

Segment Information - Segment Sales to External Customers by Product Line (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
Revenue from External Customer [Line Items]
Segment sales to external customers	$ 1,390.9	$ 1,470.8	$ 1,454.3	$ 1,425.7	$ 1,434	$ 1,518.9	$ 1,468.4	$ 1,431.3	$ 5,741.7	$ 5,852.6	$ 3,665.3
Operating Segments
Revenue from External Customer [Line Items]
Segment sales to external customers									5,741.7	5,852.6	3,665.3	[1]
Operating Segments | Packaging
Revenue from External Customer [Line Items]
Segment sales to external customers									4,477.3	4,540.3	3,431.7	[1]
Operating Segments | Paper
Revenue from External Customer [Line Items]
Segment sales to external customers									1,143.1	1,201.4	216.9	[1]
Operating Segments | Paper | White Papers
Revenue from External Customer [Line Items]
Segment sales to external customers									1,089.6	1,138.5	207
Operating Segments | Paper | Market Pulp
Revenue from External Customer [Line Items]
Segment sales to external customers									53.5	62.9	9.9
Operating Segments | Corporate and Other
Revenue from External Customer [Line Items]
Segment sales to external customers									$ 121.3	$ 110.9	$ 16.7
[1]	On October 25, 2013, we acquired Boise Inc. (Boise). Our financial results include Boise subsequent to acquisition.

Segment Information - Analysis

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	$ 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		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		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		17.6	[12]	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		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	[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		(10.3)		(18)	(26)		(17.8)		(4)
Acquisition Inventory Step-Up | Boise Inc. | Packaging
Segment Reporting Information [Line Items]
Operating Income (Loss)																					(18)
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	[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	[1]
Intersegment Eliminations | Corporate and Other
Segment Reporting Information [Line Items]
Intersegment sales																	133.8		144.9		28	[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)		(150.7)
Net sales																	(137)		(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
Mill at St. Helens, Oregon [Member]
Segment Reporting Information [Line Items]
Gain (Loss) on Disposition of Assets																	$ 6.7	[21]	$ 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.

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) $ in Millions	2 Months Ended	12 Months Ended
	Oct. 31, 2010	Dec. 31, 2015USD ($)a	Dec. 31, 2014USD ($)		Dec. 31, 2013USD ($)
Schedule Of Commitments And Contingencies [Line Items]
Capital commitments		$ 83.7	$ 94.7
Area leased under timberland cutting rights (acres) | a		83,000
Average lease renewal term		6 years
Total lease expense		$ 87.9	85.6		$ 56
Capital lease obligations		22.8	23.9
Interest paid, capital lease obligations		1.6	1.6		1.6
Purchases during period under purchase agreements		299.6	265.9		61.7
Environmental reserve		24.3
Environmental liabilities and asset retirement obligations		7.9	7.1
Number of other U.S. and Canadian containerboard producers	PCA and eight other U.S. and Canadian containerboard producers were named as defendants
Number of lawsuits filed by the plaintiffs	5
Class action lawsuit settlement		0	$ 17.6	[1]	$ 0
Asset Retirement Obligation
Schedule Of Commitments And Contingencies [Line Items]
Environmental reserve		15.8
Environmental Contingencies
Schedule Of Commitments And Contingencies [Line Items]
Environmental reserve		8.5
Other Long-Term Liabilities
Schedule Of Commitments And Contingencies [Line Items]
Environmental reserve		$ 16.4
Minimum
Schedule Of Commitments And Contingencies [Line Items]
Remaining lease term		1 year
Purchase commitments term, years		1 year
Maximum
Schedule Of Commitments And Contingencies [Line Items]
Remaining lease term		15 years
Purchase commitments term, years		20 years
[1]	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.

Commitments, Guarantees, Inde92

Commitments, Guarantees, Indemnifications, and Legal Proceedings - Schedule of Minimum Lease Payments Under Non-Cancelable Operating Leases (Details) $ in Millions	Dec. 31, 2015USD ($)
Leases, Operating [Abstract]
2,016	$ 54.4
2,017	45
2,018	36.9
2,019	25.7
2,020	17.2
Thereafter	69.2
Total	$ 248.4

Commitments, Guarantees, Inde93

Commitments, Guarantees, Indemnifications, and Legal Proceedings - Schedule of Assets Held Under Capital Lease Obligations (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Capital Leased Assets [Line Items]
Total capital lease assets, Gross	$ 28.8	$ 28.8
Less accumulated amortization	(12.2)	(10.5)
Total capital lease assets, net	16.6	18.3
Buildings
Capital Leased Assets [Line Items]
Total capital lease assets, Gross	0.3	0.3
Machinery and Equipment
Capital Leased Assets [Line Items]
Total capital lease assets, Gross	$ 28.5	$ 28.5

Commitments, Guarantees, Inde94

Commitments, Guarantees, Indemnifications, and Legal Proceedings - Schedule of Future Minimum Payments Under Capitalized Leases (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,016	$ 2.7
2,017	2.7
2,018	2.7
2,019	2.7
2,020	2.7
Thereafter	20.4
Total minimum capital lease payments	33.9
Less amounts representing interest	(11.1)
Present value of net minimum capital lease payments	22.8
Less current maturities of capital lease obligations	(1.2)	$ (1.1)
Total long-term capital lease obligations	$ 21.6	$ 22.8

Commitments, Guarantees, Inde95

Commitments, Guarantees, Indemnifications, and Legal Proceedings - Schedule of Purchase Commitments (Details) $ in Millions	Dec. 31, 2015USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,016	$ 95.3
2,017	60.3
2,018	28
2,019	28
2,020	23.4
Thereafter	77
Total	$ 312

Quarterly Financial Data - Addi

Quarterly Financial Data - Additional Information (Detail) - USD ($) $ / shares in Units, $ 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
Quarterly Financial Data [Line Items]
Net sales	$ 1,390.9		$ 1,470.8		$ 1,454.3		$ 1,425.7		$ 1,434	$ 1,518.9		$ 1,468.4		$ 1,431.3		$ 5,741.7	$ 5,852.6		$ 3,665.3
Gross profit	285		328.3		317.6		277		297	320.3		310.8		301.4		1,208	1,229.5		867.5
Operating Income (Loss)	(175.9)	[1]	(219.4)	[2]	(197.6)	[3]	(157.1)	[4]	(173.2)	(188.4)	[5]	(180.2)	[6]	(160.9)	[7]	(750)	(702.7)		(481.9)	[8]
Net income	$ 104.3	[1]	$ 127.8	[2]	$ 114	[3]	$ 90.8	[4]	$ 98.5	$ 104.4	[5]	$ 99.6	[6]	$ 90.1	[7]	$ 436.8	$ 392.6		$ 441.3
Basic income per common share	$ 1.07		$ 1.31		$ 1.16		$ 0.92		$ 1	$ 1.06		$ 1.01		$ 0.92		$ 4.47	$ 3.99		$ 4.57
Diluted income per common share	1.07	[1]	1.31	[2]	1.16	[3]	0.92	[4]	1	1.06	[5]	1.01	[6]	0.92	[7]	4.47	3.99		$ 4.52
Stock price - high	70.04		73.60		78.98		84.88		80.14	72.82		72.74		75.10		84.88	80.14
Stock price - low	$ 59.54		$ 58.29		$ 62.48		$ 73.03		$ 57.06	$ 63.11		$ 65		$ 61.35		$ 58.29	$ 57.06
Interest expense, net																$ (85.5)	$ (88.4)	[9]	$ (58.3)	[8],[10]
Income before taxes																$ 664.5	$ 614.3		$ 423.6	[8]
Correction of income statement classification					$ 6
Settled Litigation
Quarterly Financial Data [Line Items]
Operating Income (Loss)														$ 17.6
Decrease (Increase) in net income														$ (11.2)
Decrease (Increase) in net income per diluted share														$ (0.11)
DeRidder Restructuring Costs
Quarterly Financial Data [Line Items]
Operating Income (Loss)	$ (3.5)		$ (3.8)		(1)		$ 10.3		$ 18	$ 26		$ 17.8		$ 4
Decrease (Increase) in net income	$ 2.2		$ 2.3		$ 0.7		$ (6.6)		$ (11.7)	$ (16.6)		$ (11.2)		$ (2.6)
Decrease (Increase) in net income per diluted share	$ 0.02		$ 0.02		$ 0.01		$ (0.07)		$ (0.12)	$ (0.17)		$ (0.12)		$ (0.02)
Boise Inc. | Integration-Related and Other Costs
Quarterly Financial Data [Line Items]
Operating Income (Loss)	$ 3.8		$ 2.4		$ 3.7		$ 3.5		$ 6.4			$ 4.9		$ 4.1
Income before taxes										$ (4.5)
Decrease (Increase) in net income	$ (2.6)		$ (1.7)		$ (2.3)		$ (2.2)		$ (4.2)	$ (2.9)		$ (3)		$ (2.6)
Decrease (Increase) in net income per diluted share	$ (0.03)		$ (0.02)		$ (0.03)		$ (0.02)		$ (0.04)	$ (0.03)		$ (0.03)		$ (0.03)
Mill at St. Helens, Oregon [Member] | DeRidder Restructuring Costs
Quarterly Financial Data [Line Items]
Operating Income (Loss)			$ (6.7)
Decrease (Increase) in net income			$ 4.4
Decrease (Increase) in net income per diluted share			$ 0.05
Louisiana State | DeRidder Restructuring Costs
Quarterly Financial Data [Line Items]
Operating Income (Loss)							$ (3.6)
[1]	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).
[2]	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).
[3]	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.
[4]	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.
[5]	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).
[6]	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).
[7]	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).
[8]	On October 25, 2013, we acquired Boise Inc. (Boise). Our financial results include Boise subsequent to acquisition.
[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.

Subsequent Events (Details)

Subsequent Events (Details) - USD ($)	2 Months Ended
	Feb. 26, 2016	Feb. 25, 2016	Jul. 21, 2015
Subsequent Event [Line Items]
Stock Repurchase Program, Additional Amount Authorized			$ 150,000,000
Subsequent Event
Subsequent Event [Line Items]
Stock Repurchased During Period, Shares	1,868,487
Stock Repurchased During Period, Value	$ 93,400,000
Stock Repurchase Program, Additional Amount Authorized		$ 200,000,000

Schedule II - Valuation and Q98

Schedule II - Valuation and Qualifying Accounts Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance Beginning of Year	$ 13	$ 13.3	$ 5.3
Acquired Reserves	0	0	6.1
Charged to Expenses	51.6	46.8	42.3
Deductions	(49.2)	(47.1)	(40.4)
Balance End of Year	15.4	13	13.3
Allowance for Doubtful Accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance Beginning of Year	4.9	3.9	1.9
Acquired Reserves	0	0	0
Charged to Expenses	0.9	2.2	2.8
Deductions	(1.9)	(1.2)	(0.8)
Balance End of Year	3.9	4.9	3.9
Reserve for Customer Deductions
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance Beginning of Year	6.4	6.7	3.4
Acquired Reserves	0	0	3.4
Charged to Expenses	46.2	44.5	39.5
Deductions	(46.2)	(44.8)	(39.6)
Balance End of Year	6.4	6.4	6.7
Deferred Tax Asset Valuation Allowance
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance Beginning of Year	1.7	2.7	0
Acquired Reserves	0	0	2.7
Charged to Expenses	4.5	0.1	0
Deductions	(1.1)	1.1	0
Balance End of Year	$ 5.1	$ 1.7	$ 2.7