Nature of Operations and Basis of Presentation	9 Months Ended
Sep. 30, 2014
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. After the acquisition of Boise, we began reporting our business 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 16, 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. In accordance with Accounting Standards Codification (“ASC”) 280, "Segment Reporting," we recast segment information for the three and nine months ended September 30, 2013, to conform with the current period presentation. In addition, we reclassified amounts previously disclosed in "Corporate overhead" in the Consolidated Statements of Income for the three and nine months ended September 30, 2013, into "Selling, general, and administrative expenses" given that Corporate and Other is now a separately disclosed segment. With the exception of the change in accounting principle relating to our inventories described below in Note 2, Change in Accounting Principle: Inventories, none of the reclassifications affected our results of operations, financial position, or cash flows. The consolidated financial statements of PCA as of September 30, 2014, and for the three and nine months ended September 30, 2014 and 2013, are unaudited but include all adjustments (consisting only of normal recurring adjustments) that management considers necessary for a fair presentation of such financial statements. The preparation of the consolidated financial statements involves the use of estimates and accruals. Actual results may vary from those estimates. These financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and with Article 10 of SEC Regulation S-X. Accordingly, they do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete audited financial statements. Operating results for the period ended September 30, 2014, are not necessarily indicative of the results that may be expected for the year ending December 31, 2014. These consolidated financial statements should be read in conjunction with our Annual Report on Form 10-K for the year ended December 31, 2013, and the updated consolidated financial statements included in our Current Report on Form 8-K filed on May 9, 2014 (referred to as "updated 2013 Financial Statements" throughout this document). 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 for periods after October 25, 2013.

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.

After the acquisition of Boise, we began reporting our business 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 16, 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. In accordance with Accounting Standards Codification (“ASC”) 280, "Segment Reporting," we recast segment information for the three and nine months ended September 30, 2013, to conform with the current period presentation. In addition, we reclassified amounts previously disclosed in "Corporate overhead" in the Consolidated Statements of Income for the three and nine months ended September 30, 2013, into "Selling, general, and administrative expenses" given that Corporate and Other is now a separately disclosed segment. With the exception of the change in accounting principle relating to our inventories described below in Note 2, Change in Accounting Principle: Inventories, none of the reclassifications affected our results of operations, financial position, or cash flows.

The consolidated financial statements of PCA as of September 30, 2014, and for the three and nine months ended September 30, 2014 and 2013, are unaudited but include all adjustments (consisting only of normal recurring adjustments) that management considers necessary for a fair presentation of such financial statements. The preparation of the consolidated financial statements involves the use of estimates and accruals. Actual results may vary from those estimates. These financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and with Article 10 of SEC Regulation S-X. Accordingly, they do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete audited financial statements. Operating results for the period ended September 30, 2014, are not necessarily indicative of the results that may be expected for the year ending December 31, 2014. These consolidated financial statements should be read in conjunction with our Annual Report on Form 10-K for the year ended December 31, 2013, and the updated consolidated financial statements included in our Current Report on Form 8-K filed on May 9, 2014 (referred to as "updated 2013 Financial Statements" throughout this document).

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 for periods after October 25, 2013.