Packaging Corporation of America (PKG) 10-Q 3 Nov 22 2022 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2022	Oct. 28, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Entity Registrant Name	PACKAGING CORP OF AMERICA
Entity Central Index Key	0000075677
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		92,534,480
Entity File Number	1-15399
Entity Tax Identification Number	36-4277050
Entity Address, Address Line One	1 North Field Court
Entity Address, City or Town	Lake Forest
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60045
City Area Code	847
Local Phone Number	482-3000
Document Quarterly Report	true
Entity Incorporation, State or Country Code	DE
Document Transition Report	false
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	PKG
Security Exchange Name	NYSE

Consolidated Statements of Inco

Consolidated Statements of Income and Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Statement [Abstract]
Net sales	$ 2,125.9	$ 2,000.1	$ 6,499.6	$ 5,687.1
Cost of sales	(1,607.5)	(1,489.4)	(4,859.3)	(4,324)
Gross profit	518.4	510.7	1,640.3	1,363.1
Selling, general and administrative expenses	(145.2)	(144.5)	(462.9)	(435.7)
Other expense, net	(12.9)	(13.4)	(44.7)	(41.7)
Income from operations	360.3	352.8	1,132.7	885.7
Non-operating pension income	3.6	5	10.9	14.8
Interest expense, net	(16.5)	(23.9)	(55.3)	(72.2)
Income before taxes	347.4	333.9	1,088.3	828.3
Provision for income taxes	(84.9)	(83.2)	(270.1)	(203.7)
Net income	$ 262.5	$ 250.7	$ 818.2	$ 624.6
Net income per common share:
Basic	$ 2.81	$ 2.64	$ 8.74	$ 6.58
Diluted	2.80	2.63	8.70	6.55
Dividends declared per common share	$ 1.25	$ 1	$ 3.50	$ 3
Statements of Comprehensive Income:
Net income	$ 262.5	$ 250.7	$ 818.2	$ 624.6
Foreign currency translation adjustment		0.4		0.4
Changes in unrealized losses on marketable debt securities, net of tax of $0.1 million, $0.0 million, $0.5 million, and $0.1 million	(0.6)	0	(2.1)	(0.2)
Amortization of pension and postretirement plans actuarial loss and prior service cost, net of tax of ($0.4) million, ($0.8) million, ($0.7) million, and ($1.7) million	1.2	2.5	3.5	7.5
Other comprehensive income	0.6	2.9	1.4	7.7
Comprehensive income	$ 263.1	$ 253.6	$ 819.6	$ 632.3

Consolidated Statements of In_2

Consolidated Statements of Income and Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Statement [Abstract]
Changes in unrealized losses on marketable debt securities, tax	$ 0.2	$ 0	$ 0.7	$ 0.1
Amortization of pension and postretirement plans actuarial loss and prior service cost, tax	$ (0.4)	$ (0.8)	$ (1.2)	$ (2.5)

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 648.7	$ 618.7
Short-term marketable debt securities	77.7	86.1
Accounts receivable, net of allowance for credit losses and customer deductions of $20.2 million and $14.3 million as of September 30, 2022 and December 31, 2021, respectively	1,112.8	1,071
Inventories	994.9	902.5
Prepaid expenses and other current assets	67.3	47
Federal and state income taxes receivable	6.1	7.4
Total current assets	2,907.5	2,732.7
Property, plant, and equipment, net	3,813.2	3,529
Goodwill	922.4	923.5
Other intangible assets, net	277.4	308.4
Operating lease right-of-use assets	286.8	238.3
Long-term marketable debt securities	67.1	60
Other long-term assets	70	44.9
Total assets	8,344.4	7,836.8
Current liabilities:
Operating lease obligations	72.5	67.1
Finance lease obligations	1.8	1.7
Accounts payable	485.3	452.4
Dividends payable	118.8	96.3
Accrued liabilities	259.5	255
Accrued interest	25.5	12.3
Total current liabilities	963.4	884.8
Long-term liabilities:
Long-term debt	2,473.1	2,471.5
Operating lease obligations	221.4	179.3
Finance lease obligations	11.3	12.7
Deferred income taxes	513.7	465.9
Compensation and benefits	129.2	157.4
Other long-term liabilities	61.1	58
Total long-term liabilities	3,409.8	3,344.8
Commitments and contingent liabilities
Stockholders' equity:
Common stock, par value $0.01 per share, 300.0 million shares authorized, 93.7 million and 93.5 million shares issued as of September 30, 2022 and December 31, 2021, respectively	0.9	0.9
Additional paid in capital	600.6	579.4
Retained earnings	3,443.5	3,102.1
Accumulated other comprehensive loss	(73.8)	(75.2)
Total stockholders' equity	3,971.2	3,607.2
Total liabilities and stockholders' equity	$ 8,344.4	$ 7,836.8

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Millions, $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Allowance for credit losses and customer deductions	$ 20.2	$ 14.3
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	300	300
Common stock, shares issued	92.7	93.5

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Cash Flows from Operating Activities:
Net income	$ 818.2	$ 624.6
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion, and amortization of intangibles	338	311.1
Amortization of deferred financing costs	1.5	2
Share-based compensation expense	28.7	26.9
Deferred income tax provision	47.3	41.7
Loss on asset disposals	11.1	7.3
Pension and post-retirement benefits expense, net of contributions	(48.1)	(50.4)
Other, net	4	8.9
Increase in assets -
Accounts receivable	(41.6)	(234.3)
Inventories	(92.8)	(92.3)
Prepaid expenses and other current assets	(20.1)	(11.8)
Increase (decrease) in liabilities -
Accounts payable	8.9	22.3
Accrued liabilities	18.6	53.5
Federal and state income taxes receivable	1.2	(6.1)
Net cash provided by operating activities	1,074.9	703.4
Cash Flows from Investing Activities:
Additions to property, plant, and equipment	(577.1)	(366.2)
Additions to other long term assets	(5.8)	(1.8)
Proceeds from asset disposals	1.8	2.6
Purchases of marketable debt securities	(98)	(100.3)
Proceeds from sales of marketable debt securities	28.4	17.7
Proceeds from maturities of marketable debt securities	66.9	83
Other, net	1.9	0
Net cash used for investing activities	(581.9)	(365)
Cash Flows from Financing Activities:
Repayments of debt and finance lease obligations	(1.3)	(1.2)
Proceeds from issuance of debt	0	696.3
Financing costs paid	0	(8.5)
Common stock dividends paid	(304.4)	(284.8)
Repurchases of common stock	(142)
Shares withheld to cover employee restricted stock taxes	(15.3)	(11.9)
Net cash (used for) provided by financing activities	(463)	389.9
Net increase in cash and cash equivalents	30	728.3
Cash and cash equivalents, beginning of period	618.7	974.6
Cash and cash equivalents, end of period	$ 648.7	$ 1,702.9

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance at Dec. 31, 2020	$ 3,246.3	$ 0.9	$ 554.4	$ 2,835.5	$ (144.5)
Beginning Balance (in shares) at Dec. 31, 2020		94,830,000
Common stock withheld and retired to cover taxes on vested stock awards	(12)	$ (0.1)	(0.7)	(11.2)	0
Common stock withheld and retired to cover taxes on vested stock awards (in shares)		(88,000)
Common stock dividends declared	(286.2)	$ 0	0	(286.2)	0
Share-based compensation and other	27.9	$ 0.2	27.6	0.1	0
Share-based compensation expense (in shares)		249,000
Comprehensive income	632.3	$ 0	0	624.6	7.7
Ending Balance at Sep. 30, 2021	3,608.3	$ 1	581.3	3,162.8	(136.8)
Ending Balance (in shares) at Sep. 30, 2021		94,991,000
Beginning Balance at Jun. 30, 2021	3,444.3	$ 1	574.5	3,008.5	(139.7)
Beginning Balance (in shares) at Jun. 30, 2021		94,979,000
Common stock withheld and retired to cover taxes on vested stock awards	(1.4)	$ 0	(0.1)	(1.3)	0
Common stock withheld and retired to cover taxes on vested stock awards (in shares)		(10,000)
Common stock dividends declared	(95.3)	$ 0	0	(95.3)	0
Share-based compensation and other	7.1	$ 0	6.9	0.2	0
Share-based compensation expense (in shares)		22,000
Comprehensive income	253.6	$ 0	0	250.7	2.9
Ending Balance at Sep. 30, 2021	3,608.3	$ 1	581.3	3,162.8	(136.8)
Ending Balance (in shares) at Sep. 30, 2021		94,991,000
Beginning Balance at Dec. 31, 2021	3,607.2	$ 0.9	579.4	3,102.1	(75.2)
Beginning Balance (in shares) at Dec. 31, 2021		93,539,000
Common stock repurchases and retirements (in shares)		(1,032,000)
Common stock repurchases and retirements	(142)	$ 0	(8.5)	(133.5)	0
Common stock withheld and retired to cover taxes on vested stock awards	(15.3)	$ 0	(0.9)	(14.4)	0
Common stock withheld and retired to cover taxes on vested stock awards (in shares)		(110,000)
Common stock dividends declared	(328.6)	$ 0	0	(328.6)	0
Share-based compensation and other	30.3	$ 0	30.6	(0.3)	0
Share-based compensation expense (in shares)		304,000
Comprehensive income	819.6	$ 0	0	818.2	1.4
Ending Balance at Sep. 30, 2022	3,971.2	$ 0.9	600.6	3,443.5	(73.8)
Ending Balance (in shares) at Sep. 30, 2022		92,701,000
Beginning Balance at Jun. 30, 2022	3,964.5	$ 0.9	601	3,437	(74.4)
Beginning Balance (in shares) at Jun. 30, 2022		93,686,000
Common stock repurchases and retirements (in shares)		(1,032,000)
Common stock repurchases and retirements	(142)	$ 0	(8.5)	(133.5)	0
Common stock withheld and retired to cover taxes on vested stock awards	(5.9)	$ 0	(0.4)	(5.5)	0
Common stock withheld and retired to cover taxes on vested stock awards (in shares)		(43,000)
Common stock dividends declared	(116.7)	$ 0	0	(116.7)	0
Share-based compensation and other	8.2	$ 0	8.5	(0.3)	0
Share-based compensation expense (in shares)		90,000
Comprehensive income	263.1	$ 0	0	262.5	0.6
Ending Balance at Sep. 30, 2022	$ 3,971.2	$ 0.9	$ 600.6	$ 3,443.5	$ (73.8)
Ending Balance (in shares) at Sep. 30, 2022		92,701,000

Nature of Operations and Basis

Nature of Operations and Basis of Presentation	9 Months Ended
	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations and Basis of Presentation	1. 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. We are 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. We report our business in three reportable segments: Packaging, Paper, and Corporate and Other. Our Packaging segment produces a wide variety of containerboard and corrugated packaging products. The Paper segment manufactures and sells a range of communication-based papers. 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 19, Segment Information. Our Jackson, Alabama mill had historically operated as an uncoated freesheet ("UFS") paper mill, with its results of operations reported in our Paper segment. During the fourth quarter of 2020, in order to meet strong packaging demand and maintain appropriate inventory levels, we temporarily began producing linerboard on the No. 3 machine at our Jackson, Alabama mill. In the first quarter of 2021, we announced the discontinuation of production of UFS paper grades on the machine and the permanent conversion of the machine to produce linerboard and other paper-to-containerboard conversion related activities. In the third quarter of 2021, we began producing corrugating medium on the No. 1 machine at the Jackson mill (which had produced UFS paper in the past) to help satisfy our demand for containerboard, build necessary inventories, and evaluate the capability of the machine to produce containerboard on a cost-effective basis. For the periods presented in this Form 10-Q, operating results for the Jackson mill are included in both the Packaging and Paper segments, as appropriate. The consolidated financial statements of PCA as of September 30, 2022 and for the three and nine months ended September 30, 2022 and 2021 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 Regulation S-X of the Securities and Exchange Commission (SEC). Accordingly, they do not include all of the information and notes required by accounting principles generally accepted in the United States for complete audited financial statements. Operating results for the three and nine months ended September 30, 2022 are not necessarily indicative of the results that may be expected for the year ending December 31, 2022. These consolidated financial statements should be read in conjunction with our Annual Report on Form 10-K for the year ended December 31, 2021. The consolidated financial statements include the accounts of PCA and its majority-owned subsidiaries after elimination of intercompany balances and transactions.

New Accounting Standards

New Accounting Standards	9 Months Ended
	Sep. 30, 2022
Accounting Standards Update and Change in Accounting Principle [Abstract]
New Accounting Standards	2. New Accounting Standards In October 2021, the FASB issued ASU 2021-08, Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers . ASU 2021-08 requires contract assets and contract liabilities acquired in a business combination to be recognized and measured by the acquirer on the acquisition date in accordance with ASC 606, Revenue from Contracts with Customers . Under current business combination guidance in ASC 805, Business Combinations , such assets and liabilities are recognized by the acquirer at fair value on the acquisition date, whereas the new guidance requires the acquirer to recognize such assets and liabilities as if it had originated the contracts. The ASU is effective for annual periods beginning after December 15, 2022, and interim periods within those annual periods, with early adoption permitted. The Company will apply the amended guidance on a prospective basis to any business combinations that occur on or after the adoption date. In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. ASU 2020-04 provides optional guidance for a limited period of time to ease the potential burden in accounting for, or recognizing the effects of, reference rate reform on financial reporting. The amendments in this Update are elective and apply to all entities, subject to meeting certain criteria, that have contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. In January 2021, the FASB issued ASU 2021-01, which extends some of the optional expedients under Topic 848 to include derivative contracts impacted by discounting transition. Companies can apply the ASU immediately. The ASU can be adopted on a full retrospective basis as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020, or on a prospective basis to any new modification from any date within an interim period that includes or is subsequent to the date of the issuance of a final Update, up to the date that financial statements are available to be issued. The optional guidance will only be available until December 31, 2022. While the Company’s fixed-rate outstanding debt will not be impacted by the reference rate reform, the Company is still evaluating the impact of this guidance on its revolving credit facility, as the interest rate associated with any future borrowings against the revolving credit facility is based on LIBOR. Overall, the Company does not expect the guidance to have a significant impact on its financial position or related disclosures. 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

Acquisitions	9 Months Ended
	Sep. 30, 2022
Asset Acquisition [Abstract]
Acquisitions	4. Acquisitions Advance Packaging Acquisition On December 11, 2021 , PCA acquired the assets of Advance Packaging Corporation ("Advance Packaging"), an independent corrugated products producer, for $ 194.9 million, including working capital adjustments. Assets acquired include full-line corrugated products operations in Grand Rapids, Michigan. Advance Packaging is a full-service producer of corrugated packaging products, including graphics, retail displays, sustainable shipping containers, and protective packaging. Advance Packaging's financial results are included in the Packaging segment from the date of acquisition. During the second quarter of 2022, we received $ 1.9 million from the seller related to a final working capital adjustment. We recorded the adjustment as a decrease to goodwill, which decreased the purchase price to $ 193.0 million. The Company accounted for the Advance Packaging acquisition using the acquisition method of accounting in accordance with ASC 805, Business Combinations. The total purchase price has been allocated to tangible and intangible assets acquired and liabilities assumed based on respective fair values, as follows (dollars in millions): 12/31/2021 Allocation Adjustments Revised Allocation Goodwill $ 60.0 $ ( 1.0 ) $ 59.0 Other intangible assets 50.2 ( 1.4 ) 48.8 Property, plant and equipment 66.7 0.5 67.2 Other net assets 18.0 — 18.0 Net assets acquired $ 194.9 $ ( 1.9 ) $ 193.0 Goodwill is calculated as the excess of the purchase price over the fair value of the net assets acquired. Among the factors that contributed to the recognition of goodwill were Advance Packaging's commitment to continuous improvement and synergies, as well as the expected increases in PCA's containerboard integration levels. Goodwill is deductible for tax purposes. Other intangible assets, primarily customer relationships, were assigned an estimated weighted average useful life of 12.8 years. Property, plant, and equipment were assigned estimated useful lives ranging from one to 20 years .

Revenue

Revenue	9 Months Ended
	Sep. 30, 2022
Revenue from Contract with Customer [Abstract]
Revenue	3. Revenue Revenue Recognition Revenue is recognized when control of the promised goods or services is transferred to customers in an amount that reflects the consideration expected to be received in exchange for those goods or services. Sales, value added, and other taxes collected concurrently with revenue-producing activities are excluded from revenue. The following table presents our revenues disaggregated by product line (dollars in millions): Three Months Ended Nine Months Ended 2022 2021 2022 2021 Packaging $ 1,940.2 $ 1,829.4 $ 5,971.6 $ 5,171.4 Paper 165.3 150.3 468.6 457.1 Corporate and Other 20.4 20.4 59.4 58.6 Total revenue $ 2,125.9 $ 2,000.1 $ 6,499.6 $ 5,687.1 Packaging Revenue Our containerboard mills produce linerboard and corrugating medium which are papers primarily used in the production of corrugated products. The majority of our containerboard production is used internally by our corrugated products manufacturing facilities. The remaining containerboard is sold to outside domestic and export customers. Our corrugated products manufacturing plants produce a wide variety of corrugated packaging products and retail merchandise displays. We sell corrugated products to national, regional and local accounts, which are broadly diversified across industries and geographic locations. The Company recognizes revenue for its packaging products when performance obligations under the terms of a contract with a customer are satisfied. This occurs with the transfer of control of our products at a specific point in time. Based on our express terms and conditions of the sale of products to our customers, as well as terms included in contractual arrangements with our customers, we do not have an enforceable right of payment that includes a reasonable profit throughout the duration of the contract for products that do not have an alternative use. Revenue is recognized when the product is shipped from the mill or from our manufacturing facility to our customer. Certain customers may receive volume-based incentives, which are accounted for as variable consideration. We estimate these amounts based on the expected amount to be provided to customers and reduce revenue recognized. Certain customers receive a portion of their packaging products as consigned inventory with billing triggered once the customer uses or consumes the designated product. Prior to invoicing, these amounts are handled as unbilled receivables. Total unbilled receivables, which are immaterial in amount, are included in the accounts receivable financial statement caption. Paper Revenue We manufacture and sell a range of communication-based papers. Communication papers consist of cut-size office papers, and printing and converting papers. The Company recognizes revenue for its paper products when performance obligations under the terms of a contract with a customer are satisfied. This occurs with the transfer of control of our products at a specific point in time. Revenue is recognized when the product is shipped from the mill or from our manufacturing facility or distribution center to our customer. Certain customers may receive volume-based incentives, which are accounted for as variable consideration. We estimate these amounts based on the expected amount to be provided to customers and reduce revenue recognized. Corporate and Other Revenue Revenue in this segment primarily relates to Louisiana Timber Procurement Company, L.L.C. ("LTP"), a variable-interest entity that is 50 % owned by PCA and 50 % owned by Boise Cascade Company ("Boise Cascade"). 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. See Note 18, Transactions With Related Parties, for more information related to LTP. The Company recognizes revenue within this segment when performance obligations under the terms of a contract with a customer are satisfied. This occurs with the transfer of control of our products at a specific point in time. Practical Expedients and Exemption Shipping and handling fees billed to a customer are recorded on a gross basis in "Net sales" with the corresponding shipping and handling costs included in "Cost of sales" in the concurrent period as the revenue is recorded. We expense sales commissions when incurred because the amortization period is one year or less. Sales commissions are recorded in "Selling, general, and administrative expenses". We do not disclose the value of unsatisfied performance obligations for contracts with an original expected duration of one year or less.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2022
Earnings Per Share [Abstract]
Earnings Per Share	5. 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): Three Months Ended Nine Months Ended September 30, September 30, Numerator: 2022 2021 2022 2021 Net income $ 262.5 $ 250.7 $ 818.2 $ 624.6 Less: Distributed and undistributed earnings allocated to participating ( 1.9 ) ( 1.7 ) ( 6.4 ) ( 4.9 ) Net income attributable to common shareholders $ 260.6 $ 249.0 $ 811.8 $ 619.7 Denominator: Weighted average basic common shares outstanding 92.8 94.3 92.9 94.2 Effect of dilutive securities 0.4 0.4 0.4 0.4 Weighted average diluted common shares outstanding 93.2 94.7 93.3 94.6 Basic income per common share $ 2.81 $ 2.64 $ 8.74 $ 6.58 Diluted income per common share $ 2.80 $ 2.63 $ 8.70 $ 6.55

Other Expense, Net

Other Expense, Net	9 Months Ended
	Sep. 30, 2022
Other Income and Expenses [Abstract]
Other Expense, Net	6. Other Expense, Net The components of other income (expense), net, were as follows (dollars in millions): Three Months Ended Nine Months Ended September 30, September 30, 2022 2021 2022 2021 Asset disposals and write-offs $ ( 7.5 ) $ ( 6.4 ) $ ( 33.9 ) $ ( 27.3 ) Jackson mill conversion-related activities (a) ( 2.7 ) ( 3.2 ) ( 4.8 ) ( 6.1 ) Acquisition-related, facilities closure and other income (costs) (b) 0.2 ( 0.7 ) 0.4 2.7 Other ( 2.9 ) ( 3.1 ) ( 6.4 ) ( 11.0 ) Total $ ( 12.9 ) $ ( 13.4 ) $ ( 44.7 ) $ ( 41.7 ) (a) Includes charges related to the announced discontinuation of production of uncoated freesheet paper grades on the No. 3 machine at the Jackson, Alabama mill in the first quarter of 2021 associated with the permanent conversion of the machine to produce linerboard and other paper-to-containerboard conversion related activities. (b) For the three months ended September 30, 2022, includes income consisting of a gain on sale of assets related to a corrugated products facility, partially offset by charges consisting of closure costs related to corrugated products facilities. For the nine months ended September 30, 2022, includes income primarily related to insurance proceeds received for a natural disaster at one of the corrugated products facilities and a gain on sale of assets related to a corrugated products facility, partially offset by closure costs related to corrugated products facilities and acquisition and integration costs related to the December 2021 Advance Packaging acquisition. For the three months ended September 30, 2021, includes charges consisting of closure costs related to corrugated products facilities. For the nine months ended September 30, 2021, includes income primarily related to an adjustment of the required asset retirement obligation related to the 2020 closure of the San Lorenzo, California facility, a gain on sale of transportation assets, and insurance proceeds received for a natural disaster at one of the corrugated products facilities, partially offset by closure costs related to corrugated products facilities.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Income Taxes	7. Income Taxes For the three months ended September 30, 2022 and 2021, we recorded $84.9 million and $ 83.2 million of income tax expense and had an effective tax rate of 24.4 % and 24.9 %, respectively. The decrease in our effective tax rate for the three months ended September 30, 2022 compared to the same period in 2021 was primarily due to favorable employee restricted stock and performance unit vests with higher excess tax benefits and favorable state tax law changes, partially offset by higher nondeductible employee remuneration paid to covered employees. For the nine months ended September 30, 2022 and 2021, we recorded $ 270.1 and $ 203.7 million of income tax expense and had an effective tax rate of 24.8 % and 24.6 %, respectively. The increase in our effective tax rate for the nine months ended September 30, 2022 compared to the same period in 2021 was primarily due to higher nondeductible employee remuneration paid to covered employees, partially offset by favorable employee restricted stock and performance unit vests with higher excess tax benefits. Our current effective tax rate is higher than the federal statutory income tax rate of 21.0 % due primarily to the effect of state and local income taxes. During the nine months ended September 30, 2022 and 2021, cash paid for taxes, net of refunds received, was $ 221.6 million and $ 168.1 million, respectively. The increase in cash tax payments between the periods is primarily due to higher 2022 forecasted taxable income. During the three and nine months ended September 30, 2022, there were no significant changes to our uncertain tax positions. For more information, see Note 8, Income Taxes, of the Notes to Consolidated Financial Statements in “Part II, Item 8. Financial Statements and Supplementary Data” of our 2021 Annual Report on Form 10-K.

Inventories

Inventories	9 Months Ended
	Sep. 30, 2022
Inventory Disclosure [Abstract]
Inventories	8. Inventories We value our raw materials, work in process, and finished goods inventories using lower of cost, as determined by the average cost method, or net realizable value. 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): September 30, December 31, 2022 2021 Raw materials $ 381.3 $ 324.2 Work in process 16.0 16.2 Finished goods 195.0 201.0 Supplies and materials 402.6 361.1 Inventories $ 994.9 $ 902.5

Property, Plant, and Equipment

Property, Plant, and Equipment	9 Months Ended
	Sep. 30, 2022
Property, Plant and Equipment [Abstract]
Property, Plant, and Equipment	9. Property, Plant, and Equipment The components of property, plant, and equipment were as follows (dollars in millions): September 30, December 31, 2022 2021 Land and land improvements $ 193.0 $ 189.8 Buildings 1,006.6 938.7 Machinery and equipment 6,452.3 6,159.1 Construction in progress 608.4 481.0 Other 126.7 102.9 Property, plant and equipment, at cost 8,387.0 7,871.5 Less accumulated depreciation ( 4,573.8 ) ( 4,342.5 ) Property, plant, and equipment, net $ 3,813.2 $ 3,529.0 Depreciation expense for the three months ended September 30, 2022 and 2021 wa s $ 103.2 million a nd $ 95.5 million, respectively. During the nine months ended September 30, 2022 and 2021, depreciation expense was $ 305.3 million and $ 279.9 million, respectively. We recognized $ 3.1 million and $ 3.6 million of incremental depreciation expense during the nine months ended September 30, 2022 and 2021, respectively, as a result of Jackson mill conversion-related activities and closure costs related to corrugated products facilities. At September 30, 2022 and December 31, 2021, purchases of property, plant, and equipment included in accounts payable were $ 91.4 million and

Goodwill and Intangible Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 30, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	10. 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 September 30, 2022 and December 31, 2021 we had $ 922.4 million and $ 923.5 million, respectively, of goodwill recorded in our Packaging segment, which represents the entire goodwill balance reported on our Consolidated Balance Sheets. Changes in the carrying amount of our goodwill are as follows (dollars in millions): Goodwill Balance at January 1, 2022 $ 923.5 Acquisitions (a) ( 1.0 ) Adjustment related to sale of corrugated assets (b) ( 0.1 ) Balance at September 30, 2022 $ 922.4 (a) During the nine months ended September 30, 2022, the Company recorded a $ 1.0 million adjustment to decrease the goodwill balance for the Company's December 2021 acquisition of Advance Packaging. (b) During the three months ended September 30, 2022, a corrugated products facility sold part of its operations, which primarily included existing inventory. As a result, the Company recorded a $ 0.1 million adjustment to decrease the goodwill balance . Intangible Assets Intangible assets are primarily comprised of customer relationships and trademarks and trade names. The weighted average remaining useful life, gross carrying amount, and accumulated amortization of our intangible assets were as follows (dollars in millions): September 30, 2022 December 31, 2021 Weighted Gross Accumulated Weighted Gross Accumulated Customer relationships (c) 8.4 $ 546.0 $ 282.0 8.5 $ 551.1 $ 254.9 Trademarks and trade names (c) 7.4 41.3 28.0 8.4 37.6 25.5 Other (c) 3.6 4.5 4.4 2.2 4.4 4.3 Total intangible assets (excluding goodwill) 8.4 $ 591.8 $ 314.4 8.5 $ 593.1 $ 284.7 (c) In connection with the December 2021 acquisition of Advance Packaging, the Company recorded intangible assets of $ 47.3 million for customer relationships, $ 2.8 million for trade names, and $ 0.1 million for other intangibles. During the three months ended June 30, 2022, the Company made a $ 1.4 million net adjustment based on the final valuation received for the intangible assets. This adjustment resulted in a revision to the original allocations for customer relationships and trade names. As of June 30, 2022, the revised allocations for customer relationships and trade names were $ 42.2 million and $ 6.5 million, respectively. During the nine months ended September 30, 2022 and 2021, amortization expense was $ 29.7 million and $ 28.2 million, respectively.

Accrued Liabilities

Accrued Liabilities	9 Months Ended
	Sep. 30, 2022
Accrued Liabilities [Abstract]
Accrued Liabilities	11. Accrued Liabilities The components of accrued liabilities were as follows (dollars in millions): September 30, December 31, 2022 2021 Compensation and benefits $ 146.5 $ 157.1 Customer rebates and other credits 40.3 36.9 Franchise, property, sales and use taxes 29.0 17.6 Medical insurance and workers’ compensation 25.9 26.9 Environmental liabilities and asset retirement obligations 3.8 4.0 Severance, retention, and relocation 1.9 2.7 Other 12.1 9.8 Total $ 259.5 $ 255.0

Debt

Debt	9 Months Ended
	Sep. 30, 2022
Debt Disclosure [Abstract]
Debt	12. Debt For the nine months ended September 30, 2022 and 2021, cash payments for interest were $ 50.6 million and $ 55.2 million, respectively. Included in interest expense, net is the amortization of financing costs. For the three months ended September 30, 2022 and 2021, amortization of financing costs was $ 0.4 million and $ 0.5 million, respectively, and during the nine months ended September 30, 2022 and 2021, amortization of financing costs was $ 1.2 million and $ 1.5 million, respectively. At September 30, 2022, we had $ 2,491.4 million of fixed-rate senior notes outstanding. The fair value of our fixed-rate debt was estimated to be $ 2,004.1 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) within the fair value hierarchy, which is further defined in Note 2, Summary of Significant Accounting Policies, of the Notes to Consolidated Financial Statements in "Part II, Item 8. Financial Statements and Supplementary Data" of our 2021 Annual Report on Form 10-K. For more information on our long-term debt and interest rates on that debt, see Note 11, Debt, of the Notes to Consolidated Financial Statements in "Part II, Item 8. Financial Statements and Supplementary Data" of our 2021 Annual Report on Form 10-K.

Cash, Cash Equivalents, and Mar

Cash, Cash Equivalents, and Marketable Debt Securities	9 Months Ended
	Sep. 30, 2022
Cash, Cash Equivalents, and Short-Term Investments [Abstract]
Cash, Cash Equivalents, and Marketable Debt Securities	13. Cash, Cash Equivalents, and Marketable Debt Securities The following table shows the Company’s cash and available-for-sale ("AFS") debt securities by major asset category at September 30, 2022 and December 31, 2021 (in millions): September 30, 2022 Adjusted Unrealized Unrealized Fair Cash and Short-Term Long-Term Cash and cash equivalents $ 643.0 $ — $ — $ 643.0 $ 643.0 $ — $ — Level 1 (a) : U.S. Treasury securities 30.0 — ( 0.6 ) 29.4 3.0 13.7 12.7 Money market funds 0.7 — — 0.7 0.7 — — Subtotal 30.7 — ( 0.6 ) 30.1 3.7 13.7 12.7 Level 2 (b) : Corporate debt securities 117.0 — ( 2.5 ) 114.5 1.2 60.8 52.5 U.S. government agency securities 3.2 — ( 0.1 ) 3.1 — 1.2 1.9 Certificates of deposit 2.8 — — 2.8 0.8 2.0 — Subtotal 123.0 — ( 2.6 ) 120.4 2.0 64.0 54.4 Total $ 796.7 $ — $ ( 3.2 ) $ 793.5 $ 648.7 $ 77.7 $ 67.1 December 31, 2021 Adjusted Unrealized Unrealized Fair Cash and Short-Term Long-Term Cash and cash equivalents $ 612.3 $ — $ — $ 612.3 $ 612.3 $ — $ — Level 1 (a) : U.S. Treasury securities 26.4 — ( 0.1 ) 26.3 2.0 14.7 9.6 Money market funds 0.9 — — 0.9 0.9 — — Subtotal 27.3 — ( 0.1 ) 27.2 2.9 14.7 9.6 Level 2 (b) : Corporate debt securities 118.9 — ( 0.3 ) 118.6 3.5 66.0 49.1 U.S. government agency securities 4.8 — — 4.8 — 3.5 1.3 Certificates of deposit 1.9 — — 1.9 — 1.9 — Subtotal 125.6 — ( 0.3 ) 125.3 3.5 71.4 50.4 Total $ 765.2 $ — $ ( 0.4 ) $ 764.8 $ 618.7 $ 86.1 $ 60.0 (a) Valuations based on quoted prices for identical assets or liabilities in active markets. (b) 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. For the three and nine months ended September 30, 2022 and 2021, net realized gains and losses on the sales and maturities of certain marketable debt securities were insignificant. The Company invests in highly rated securities, with the primary objective of minimizing the potential risk of principal loss. The Company’s investment policy requires securities to be investment grade and limits the amount of credit exposure to any one issuer. The maturities of the Company’s long-term marketable debt securities generally range from one to two years . Fair values were determined for each individual marketable debt security in the investment portfolio. When evaluating a marketable debt security for impairment, PCA reviews factors such as the duration and extent to which the fair value of the marketable debt security is less than its cost, the financial condition of the issuer and any changes thereto, the general market condition in which the issuer operates, and PCA’s intent to sell, or whether it will be more likely than not be required to sell, the marketable debt security before recovery of its amortized cost basis. As of September 30, 2022 and December 31, 2021, we do no t consider any of the impairments related to our marketable debt securities to be the result of credit losses. Therefore, we have no t recorded an allowance for credit losses related to our marketable debt securities. All unrealized gains and losses were recorded in other comprehensive income (OCI). The following tables provide information about the Company’s marketable debt securities that have been in a continuous loss position as of September 30, 2022 and December 31, 2021 (in millions, except number of marketable debt securities in a loss position): September 30, 2022 Fair Value of Number of Marketable Unrealized Losses < 12 Months Fair Value of Number of Marketable Unrealized Losses Corporate debt securities $ 103.1 165 $ 2.1 $ 9.2 10 $ 0.5 U.S. Treasury securities 23.0 22 0.4 3.4 6 0.1 U.S. government agency securities 2.9 5 0.1 0.3 1 — Certificates of deposit 0.8 2 — — — — $ 129.8 194 $ 2.6 $ 12.9 17 $ 0.6 December 31, 2021 Fair Value of Number of Marketable Unrealized Corporate debt securities $ 106.9 153 $ 0.3 U.S. Treasury securities 22.4 27 0.1 U.S. government agency securities 4.8 6 — Certificates of deposit 0.5 1 — $ 134.6 187 $ 0.4 (c) For the period ended December 31, 2021, there were no debt securities in a continuous loss position greater than or equal to 12 months.

Employee Benefit Plans and Othe

Employee Benefit Plans and Other Postretirement Benefits	9 Months Ended
	Sep. 30, 2022
Retirement Benefits [Abstract]
Employee Benefit Plans and Other Postretirement Benefits	14. Employee Benefit Plans and Other Postretirement Benefits The components of net periodic benefit cost for our pension plans were as follows (dollars in millions): Pension Plans Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Service cost $ 4.6 $ 5.4 $ 14.4 $ 16.0 Interest cost 8.6 7.4 26.0 22.2 Expected return on plan assets ( 13.9 ) ( 15.8 ) ( 41.8 ) ( 47.3 ) Net amortization of unrecognized amounts Prior service cost 0.9 1.0 2.7 2.9 Actuarial loss 0.9 2.6 2.6 7.8 Net periodic benefit cost $ 1.1 $ 0.6 $ 3.9 $ 1.6 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 additional discretionary contributions based on the funded status of the plans, tax deductibility, income from operations, and other factors. During the three and nine months ended September 30, 2022 and 2021, payments to our nonqualified pension plans were insignificant. During both the three and nine months ended September 30, 2022 and 2021, we made contributions of $ 50.0 million to our qualified pension plans. We do no t have a required minimum contribution amount for 2022, but we expect to make discretionary contributions to our plans. For the three and nine months ended September 30, 2022 and 2021, the net periodic benefit cost for our postretirement plans was insignificant.

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement, Noncash Expense [Abstract]
Share-Based Compensation	15. Share-Based Compensation The Company has a long-term equity incentive plan, which allows for grants of restricted stock, performance awards, stock appreciation rights, and stock options to directors, officers, and employees, as well as others who engage in services for PCA. On February 25, 2020, our board of directors approved and, on May 5, 2020, our stockholders approved, the amendment and restatement of the plan. The amendment extended the plan’s term to May 5, 2030 and increased the number of shares of common stock available for issuance under the plan by 1.4 million shares. The total number of shares authorized for past and future awards is 12.0 million shares. As of September 30, 2022, assuming performance units are paid out at the target level of performance, 1.0 million shares were available for future grants under the current plan . Forfeitures are added back to the pool of shares of common stock available to be granted at a future date. The following table presents restricted stock and performance unit award activity for the nine months ended September 30, 2022: Restricted Stock Performance Units Shares Weighted Shares Weighted Outstanding at January 1, 2022 651,448 $ 109.16 358,092 $ 105.38 Granted 175,047 145.63 133,017 148.71 Vested (a) ( 151,087 ) 115.46 ( 132,404 ) 136.62 Forfeitures ( 14,245 ) 120.47 ( 256 ) 145.26 Outstanding at September 30, 2022 661,163 $ 117.13 358,449 $ 109.89 (a) Upon vesting of the performance unit awards, PCA issued 144,193 shares, which included 11,789 shares for dividends accrued during the vesting period. Compensation Expense Our share-based compensation expense is primarily 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): Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Restricted stock $ 4.1 $ 3.9 $ 18.7 $ 18.4 Performance units 3.1 2.9 10.0 8.5 Total share-based compensation expense 7.2 6.8 28.7 26.9 Income tax benefit ( 1.8 ) ( 1.7 ) ( 7.2 ) ( 6.8 ) Share-based compensation expense, net of tax benefit $ 5.4 $ 5.1 $ 21.5 $ 20.1 The fair value of restricted stock is determined based on the closing price of the Company’s stock on the grant date. Compensation expense, net of estimated forfeitures, is recorded over the requisite service period. As PCA’s Board of Directors has the ability to accelerate the vesting of these awards upon an employee’s retirement, the Company accelerates the recognition of compensation expense for certain employees approaching normal retirement age. Performance unit awards granted to certain key employees are earned based on the achievement of defined performance rankings of Return on Invested Capital (ROIC) or Total Shareholder Return (TSR) compared to ROIC and TSR for peer companies. For performance unit awards made in 2022 and 2021, in terms of grant date value, 50 % used TSR as the performance measure and 50 % used ROIC as the performance measure. The ROIC component of performance unit awards is valued based on the closing price of the stock on the grant date. As the ROIC component contains a performance condition, compensation expense, net of estimated forfeitures, is recorded over the requisite service period based on the most probable number of awards expected to vest. The TSR component of performance unit awards is valued using a Monte Carlo simulation as the TSR component contains a market condition. The Monte Carlo simulation estimates the fair value of the TSR component based on the expected term of the award, a risk-free interest rate, expected dividends, and expected volatility of the Company’s common stock and the common stock of the peer companies. Compensation expense is recorded ratably over the expected term of the award. The unrecognized compensation expense for all share-based awards at September 30, 2022 was as follows (dollars in millions): September 30, 2022 Unrecognized Remaining Restricted stock $ 31.4 2.6 Performance units 22.8 2.3 Total unrecognized share-based compensation expense $ 54.2 2.5

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2022
Equity [Abstract]
Stockholders' Equity	16. Stockholders' Equity Dividends During the nine months ended September 30, 2022, we paid $304.4 million of dividends to shareholders. On May 18, 2022, PCA announced an increase of its quarterly cash dividend on its common stock from an annual rate of $ 4.00 per share to $ 5.00 per share. On September 21, 2022, PCA’s Board of Directors declared a regular quarterly cash dividend of $ 1.25 per share of common stock, which was paid on October 17, 2022 to shareholders of record as of October 3, 2022. The dividend payment was $ 115.9 million. Repurchases of Common Stock On January 26, 2022, PCA announced that its Board of Directors authorized the repurchase of an additional $ 1 billion of the Company’s outstanding common stock. 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. During the three and nine months ended September 30, 2022, we paid $ 142.0 million to repurchase 1.0 million shares of common stock. All shares repurchased have been retired. At September 30, 2022, $ 858.0 million of the authorized amount remained available for repurchase of the Company's common stock. Accumulated Other Comprehensive Income (Loss) Changes in accumulated other comprehensive income (loss) (AOCI) by component were as follows (dollars in millions). Amounts in parentheses indicate losses: Unrealized Unrealized Loss Unfunded Total Balance at January 1, 2022 $ ( 0.2 ) $ ( 0.2 ) $ ( 74.8 ) $ ( 75.2 ) Other comprehensive income before reclassifications, net of tax — ( 2.1 ) — ( 2.1 ) Amounts reclassified from AOCI, net of tax — — 3.5 3.5 Balance at September 30, 2022 $ ( 0.2 ) $ ( 2.3 ) $ ( 71.3 ) $ ( 73.8 ) Reclassifications out of AOCI were as follows (dollars in millions). Amounts in parentheses indicate expenses in the Consolidated Statements of Income: Amounts Reclassified from AOCI Three Months Ended September 30, Nine Months Ended September 30, Details about AOCI Components 2022 2021 2022 2021 Unfunded employee benefit obligations (a) Amortization of prior service costs $ ( 0.8 ) $ ( 0.8 ) $ ( 2.4 ) $ ( 2.5 ) See (a) below Amortization of actuarial losses ( 0.8 ) ( 2.5 ) ( 2.3 ) ( 7.5 ) See (a) below ( 1.6 ) ( 3.3 ) ( 4.7 ) ( 10.0 ) Total before tax 0.4 0.8 1.2 2.5 Tax benefit $ ( 1.2 ) $ ( 2.5 ) $ ( 3.5 ) $ ( 7.5 ) Net of tax (a) These AOCI components are included in the computation of net pension and postretirement benefit costs. See Note 14, Employee Benefit Plans and Other Postretirement Benefits, for additional information.

Concentrations of Risk

Concentrations of Risk	9 Months Ended
	Sep. 30, 2022
Risks and Uncertainties [Abstract]
Concentration of Risk	17. Concentrations of Risk Our Paper segment has a long-standing commercial and contractual relationship with Office Depot, our largest customer in the paper business. This relationship exposes us to a significant concentration of business and financial risk. Our sales to Office Depot represent approximately 4 % of our total Company sales revenue for both the nine month periods ended September 30, 2022 and 2021, respectively, and approximately 50 % and 48 % of our Paper segment sales revenue for both of those periods, respectively. For the full year 2021, sales to Office Depot represented 51 % of our Paper segment sales. At September 30, 2022 and December 31, 2021, we had $ 43.5 million and $ 49.8 million of accounts receivable due from Office Depot, respectively, which represents approximately 4 % of our total Company accounts receivable for the same periods.

Transactions With Related Parti

Transactions With Related Parties	9 Months Ended
	Sep. 30, 2022
Related Party Transactions [Abstract]
Transactions With Related Parties	18. 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 $ 4.1 million at September 30, 2022 and $ 3.5 million at December 31, 2021. During the three months ended September 30, 2022 and 2021, we recorded $ 23.1 million and $ 22.3 million, respectively, and during the nine months ended September 30, 2022 and 2021, we recorded $ 67.4 million and $ 63.3 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". During the three months ended September 30, 2022 and 2021, fiber purchases from related parties were $ 3.4 million and $ 3.6 million , respectively, and during the nine months ended September 30, 2022 and 2021, fiber purchases from related parties were $ 10.7 million and $ 10.3 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	9 Months Ended
	Sep. 30, 2022
Segment Reporting [Abstract]
Segment Information	19. 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 requires distinct operating and marketing strategies. Our Jackson, Alabama mill had historically operated as a UFS mill, with its results of operations reported in our Paper segment. During the fourth quarter of 2020, in order to meet strong packaging demand and maintain appropriate inventory levels, we temporarily began producing linerboard on the No. 3 machine at our Jackson, Alabama mill. In the first quarter of 2021, we announced the discontinuation of production of UFS paper grades on the machine and the permanent conversion of the machine to produce linerboard and other paper-to-containerboard conversion related activities. In the third quarter of 2021, we began producing corrugating medium on the No. 1 machine at the Jackson mill (which had produced UFS paper in the past) to help satisfy our demand for containerboard, build necessary inventories, and evaluate the capability of the machine to produce containerboard on a cost-effective basis. For the periods presented, operating results for the Jackson mill are included in both the Packaging and Paper segments, as appropriate. Each segment’s profits and losses are measured on operating profits before interest expense, net, non-operating pension income, and income taxes. For certain allocated expenses, the related assets and liabilities remain in the Corporate and Other segment. Selected financial information by reportable segment was as follows (dollars in millions): Sales, net Three Months Ended September 30, 2022 Trade Intersegment Total Operating Income (Loss) Packaging $ 1,935.1 $ 5.1 $ 1,940.2 $ 359.2 (a) Paper 165.3 — 165.3 26.1 (a) Corporate and Other 25.5 37.8 63.3 ( 25.0 ) Intersegment eliminations — ( 42.9 ) ( 42.9 ) — $ 2,125.9 $ — $ 2,125.9 360.3 Non-operating pension income 3.6 Interest expense, net ( 16.5 ) Income before taxes $ 347.4 Sales, net Three Months Ended September 30, 2021 Trade Intersegment Total Operating Income (Loss) Packaging $ 1,825.0 $ 4.4 $ 1,829.4 $ 365.2 (b) Paper 150.3 — 150.3 11.0 (b) Corporate and Other 24.8 36.5 61.3 ( 23.4 ) (b) Intersegment eliminations — ( 40.9 ) ( 40.9 ) — $ 2,000.1 $ — $ 2,000.1 352.8 Non-operating pension income 5.0 Interest expense, net ( 23.9 ) (b) Income before taxes $ 333.9 Sales, net Nine Months Ended September 30, 2022 Trade Intersegment Total Operating Income (Loss) Packaging $ 5,956.8 $ 14.8 $ 5,971.6 $ 1,141.3 (a) Paper 468.6 — 468.6 71.2 (a) Corporate and Other 74.2 110.6 184.8 ( 79.8 ) Intersegment eliminations — ( 125.4 ) ( 125.4 ) — $ 6,499.6 $ — $ 6,499.6 1,132.7 Non-operating pension income 10.9 Interest expense, net ( 55.3 ) Income before taxes $ 1,088.3 Sales, net Nine Months Ended September 30, 2021 Trade Intersegment Total Operating Income (Loss) Packaging $ 5,159.3 $ 12.1 $ 5,171.4 $ 940.3 (b) Paper 457.0 0.1 457.1 22.3 (b) Corporate and Other 70.8 101.0 171.8 ( 76.9 ) (b) Intersegment eliminations — ( 113.2 ) ( 113.2 ) — $ 5,687.1 $ — $ 5,687.1 885.7 Non-operating pension income 14.8 Interest expense, net ( 72.2 ) (b) Income before taxes $ 828.3 (a) The three and nine months ended September 30, 2022 include the following: 1. $ 3.9 million and $ 9.4 million, respectively, of charges related to the announced discontinuation of production of UFS paper grades on the No. 3 machine at the Jackson, Alabama mill associated with the permanent conversion of the machine to produce linerboard and other paper-to-containerboard conversion related activities. 2. $ 0.2 million of charges and $ 0.2 million of income, respectively, consisting of closure costs related to corrugated products facilities and acquisition and integration costs related to the December 2021 Advance Packaging Corporation acquisition, partially offset by a gain on sale of assets related to a corrugated products facility. For the nine months ended September 30, 2022, these costs were offset by insurance proceeds received for a natural disaster at one of the corrugated products facilities and a favorable lease buyout for a closed corrugated products facility. (b) The three and nine months ended September 30, 2021 include the following: 1. $ 4.5 million and $ 9.4 million, respectively, of charges related to the announced discontinuation of production of UFS paper grades on the No. 3 machine at the Jackson, Alabama mill in the first quarter of 2021 associated with the permanent conversion of the machine to produce linerboard and other paper-to-containerboard conversion related activities. 2. $ 2.7 million and $ 0.1 million, respectively, of charges consisting of closure costs related to corrugated products facilities. For the nine months ended September 30, 2021, these costs are partially offset by income primarily consisting of an adjustment of the required asset retirement obligation related to the 2020 closure of the San Lorenzo, California facility, a gain on sale of transportation assets, and insurance proceeds received for a natural disaster at one of the corrugated products facilities. 3. $ 0.5 million of costs related to the Company's September 2021 debt refinancing.

Commitments, Guarantees, Indemn

Commitments, Guarantees, Indemnifications and Legal Proceedings	9 Months Ended
	Sep. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments, Guarantees, Indemnifications and Legal Proceedings	20. 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, capital commitments, lease obligations, and purchase commitments for goods and services, and legal proceedings, all of which are discussed in Note 11, Debt, and Note 21, Commitments, Guarantees, Indemnifications, and Legal Proceedings, of the Notes to Consolidated Financial Statements in "Part II, Item 8. Financial Statements and Supplementary Data" of our 2021 Annual Report on Form 10-K. Guarantees and Indemnifications We provide guarantees, indemnifications, and other assurances to third parties in the normal course of our business. These include tort indemnifications, product guarantees, environmental assurances, and representations and warranties in commercial agreements. At September 30, 2022, 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. DeRidder Mill Incident On February 8, 2017 , a tank located in the pulp mill at the Company's DeRidder, Louisiana facility exploded, resulting in three contractor fatalities and other injuries. The Company has been served with multiple lawsuits involving the decedents and other allegedly injured parties, alleging negligence on the part of the Company and claiming compensatory and punitive damages. The Company is vigorously defending these lawsuits. The Company believes that these suits are covered by its liability insurance policies, subject to an aggregate $ 1.0 million deductible, which has been satisfied in full as a result of settlement of various lawsuits and fees and expenses incurred by the Company. Cases involving nine plaintiffs are pending in the U.S. District Court for the Middle District of Louisiana and one case remains pending in state court in Alabama. One case previously dismissed by the federal district court for the Western District of Louisiana has been appealed by the plaintiff to the United States Court of Appeals for the Fifth Circuit. The Fifth Circuit Court of Appeals affirmed such dismissal. The remaining lawsuits pending in federal district court and state court are in the early stages. Accordingly, the Company is unable to estimate a range of reasonable possible losses at this time. The Company has cooperated with investigations from the U.S. Occupational Health and Safety Administration ("OSHA"), the U.S. Chemical Safety Board ("CSB") and the U.S. Environmental Protection Agency ("EPA"). The U.S. Chemical Safety Board completed its investigation and issued its report during the second quarter of 2018. The Company settled with OSHA during the second quarter of 2018 and paid approximately $ 40,000 in penalties for citations. In May 2017, the EPA conducted an on-site inspection of the facility to assess compliance with the Clean Air Act, Risk Management Program ("RMP"). The Company provided additional information to the EPA promptly after the inspection to address certain areas of concern ("AOCs") observed during the inspection. Since the inspection in 2017, PCA performed several voluntary activities to address the AOCs presented in the EPA's inspection report and has removed the RMP covered process from the facility. In January 2021, the EPA and U.S. Department of Justice ("DOJ") initiated civil judicial enforcement discussions with PCA. During the third quarter of 2022, we reached a settlement with the agencies and will pay a civil penalty of $ 2.5 million. The Company did not admit liability for violation of the Clean Air Act in connection with the settlement. The settlement is subject to a 45-day notice and comment period which is pending as of the time of this filing. Legal Proceedings We are also a party to various 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.

Acquisitions (Tables)

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2022
Asset Acquisition [Abstract]
Schedule of Tangible and Intangible Assets Acquired and Liabilities Assumed	The total purchase price has been allocated to tangible and intangible assets acquired and liabilities assumed based on respective fair values, as follows (dollars in millions): 12/31/2021 Allocation Adjustments Revised Allocation Goodwill $ 60.0 $ ( 1.0 ) $ 59.0 Other intangible assets 50.2 ( 1.4 ) 48.8 Property, plant and equipment 66.7 0.5 67.2 Other net assets 18.0 — 18.0 Net assets acquired $ 194.9 $ ( 1.9 ) $ 193.0

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 30, 2022
Revenue from Contract with Customer [Abstract]
Summary of Revenues Disaggregated by Product Line	The following table presents our revenues disaggregated by product line (dollars in millions): Three Months Ended Nine Months Ended 2022 2021 2022 2021 Packaging $ 1,940.2 $ 1,829.4 $ 5,971.6 $ 5,171.4 Paper 165.3 150.3 468.6 457.1 Corporate and Other 20.4 20.4 59.4 58.6 Total revenue $ 2,125.9 $ 2,000.1 $ 6,499.6 $ 5,687.1

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2022
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): Three Months Ended Nine Months Ended September 30, September 30, Numerator: 2022 2021 2022 2021 Net income $ 262.5 $ 250.7 $ 818.2 $ 624.6 Less: Distributed and undistributed earnings allocated to participating ( 1.9 ) ( 1.7 ) ( 6.4 ) ( 4.9 ) Net income attributable to common shareholders $ 260.6 $ 249.0 $ 811.8 $ 619.7 Denominator: Weighted average basic common shares outstanding 92.8 94.3 92.9 94.2 Effect of dilutive securities 0.4 0.4 0.4 0.4 Weighted average diluted common shares outstanding 93.2 94.7 93.3 94.6 Basic income per common share $ 2.81 $ 2.64 $ 8.74 $ 6.58 Diluted income per common share $ 2.80 $ 2.63 $ 8.70 $ 6.55

Other Expense, Net (Tables)

Other Expense, Net (Tables)	9 Months Ended
	Sep. 30, 2022
Other Income and Expenses [Abstract]
Components of Other Income (Expense), Net	The components of other income (expense), net, were as follows (dollars in millions): Three Months Ended Nine Months Ended September 30, September 30, 2022 2021 2022 2021 Asset disposals and write-offs $ ( 7.5 ) $ ( 6.4 ) $ ( 33.9 ) $ ( 27.3 ) Jackson mill conversion-related activities (a) ( 2.7 ) ( 3.2 ) ( 4.8 ) ( 6.1 ) Acquisition-related, facilities closure and other income (costs) (b) 0.2 ( 0.7 ) 0.4 2.7 Other ( 2.9 ) ( 3.1 ) ( 6.4 ) ( 11.0 ) Total $ ( 12.9 ) $ ( 13.4 ) $ ( 44.7 ) $ ( 41.7 ) (a) Includes charges related to the announced discontinuation of production of uncoated freesheet paper grades on the No. 3 machine at the Jackson, Alabama mill in the first quarter of 2021 associated with the permanent conversion of the machine to produce linerboard and other paper-to-containerboard conversion related activities. (b) For the three months ended September 30, 2022, includes income consisting of a gain on sale of assets related to a corrugated products facility, partially offset by charges consisting of closure costs related to corrugated products facilities. For the nine months ended September 30, 2022, includes income primarily related to insurance proceeds received for a natural disaster at one of the corrugated products facilities and a gain on sale of assets related to a corrugated products facility, partially offset by closure costs related to corrugated products facilities and acquisition and integration costs related to the December 2021 Advance Packaging acquisition. For the three months ended September 30, 2021, includes charges consisting of closure costs related to corrugated products facilities. For the nine months ended September 30, 2021, includes income primarily related to an adjustment of the required asset retirement obligation related to the 2020 closure of the San Lorenzo, California facility, a gain on sale of transportation assets, and insurance proceeds received for a natural disaster at one of the corrugated products facilities, partially offset by closure costs related to corrugated products facilities.

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2022
Inventory Disclosure [Abstract]
Components of Inventories	The components of inventories were as follows (dollars in millions): September 30, December 31, 2022 2021 Raw materials $ 381.3 $ 324.2 Work in process 16.0 16.2 Finished goods 195.0 201.0 Supplies and materials 402.6 361.1 Inventories $ 994.9 $ 902.5

Property, Plant, and Equipment

Property, Plant, and Equipment (Tables)	9 Months Ended
	Sep. 30, 2022
Property, Plant and Equipment [Abstract]
Components of Property, Plant, and Equipment	The components of property, plant, and equipment were as follows (dollars in millions): September 30, December 31, 2022 2021 Land and land improvements $ 193.0 $ 189.8 Buildings 1,006.6 938.7 Machinery and equipment 6,452.3 6,159.1 Construction in progress 608.4 481.0 Other 126.7 102.9 Property, plant and equipment, at cost 8,387.0 7,871.5 Less accumulated depreciation ( 4,573.8 ) ( 4,342.5 ) Property, plant, and equipment, net $ 3,813.2 $ 3,529.0

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	Changes in the carrying amount of our goodwill are as follows (dollars in millions): Goodwill Balance at January 1, 2022 $ 923.5 Acquisitions (a) ( 1.0 ) Adjustment related to sale of corrugated assets (b) ( 0.1 ) Balance at September 30, 2022 $ 922.4 (a) During the nine months ended September 30, 2022, the Company recorded a $ 1.0 million adjustment to decrease the goodwill balance for the Company's December 2021 acquisition of Advance Packaging. (b) During the three months ended September 30, 2022, a corrugated products facility sold part of its operations, which primarily included existing inventory. As a result, the Company recorded a $ 0.1 million adjustment to decrease the goodwill balance .
Components of Intangible Assets	The weighted average remaining useful life, gross carrying amount, and accumulated amortization of our intangible assets were as follows (dollars in millions): September 30, 2022 December 31, 2021 Weighted Gross Accumulated Weighted Gross Accumulated Customer relationships (c) 8.4 $ 546.0 $ 282.0 8.5 $ 551.1 $ 254.9 Trademarks and trade names (c) 7.4 41.3 28.0 8.4 37.6 25.5 Other (c) 3.6 4.5 4.4 2.2 4.4 4.3 Total intangible assets (excluding goodwill) 8.4 $ 591.8 $ 314.4 8.5 $ 593.1 $ 284.7 (c) In connection with the December 2021 acquisition of Advance Packaging, the Company recorded intangible assets of $ 47.3 million for customer relationships, $ 2.8 million for trade names, and $ 0.1 million for other intangibles. During the three months ended June 30, 2022, the Company made a $ 1.4 million net adjustment based on the final valuation received for the intangible assets. This adjustment resulted in a revision to the original allocations for customer relationships and trade names. As of June 30, 2022, the revised allocations for customer relationships and trade names were $ 42.2 million and $ 6.5 million, respectively.

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	9 Months Ended
	Sep. 30, 2022
Accrued Liabilities [Abstract]
Components of Accrued Liabilities	The components of accrued liabilities were as follows (dollars in millions): September 30, December 31, 2022 2021 Compensation and benefits $ 146.5 $ 157.1 Customer rebates and other credits 40.3 36.9 Franchise, property, sales and use taxes 29.0 17.6 Medical insurance and workers’ compensation 25.9 26.9 Environmental liabilities and asset retirement obligations 3.8 4.0 Severance, retention, and relocation 1.9 2.7 Other 12.1 9.8 Total $ 259.5 $ 255.0

Cash, Cash Equivalents, and M_2

Cash, Cash Equivalents, and Marketable Debt Securities (Tables)	9 Months Ended
	Sep. 30, 2022
Cash, Cash Equivalents, and Short-Term Investments [Abstract]
Schedule of Cash and Available-For-Sale Debt Securities by Major Asset Category	The following table shows the Company’s cash and available-for-sale ("AFS") debt securities by major asset category at September 30, 2022 and December 31, 2021 (in millions): September 30, 2022 Adjusted Unrealized Unrealized Fair Cash and Short-Term Long-Term Cash and cash equivalents $ 643.0 $ — $ — $ 643.0 $ 643.0 $ — $ — Level 1 (a) : U.S. Treasury securities 30.0 — ( 0.6 ) 29.4 3.0 13.7 12.7 Money market funds 0.7 — — 0.7 0.7 — — Subtotal 30.7 — ( 0.6 ) 30.1 3.7 13.7 12.7 Level 2 (b) : Corporate debt securities 117.0 — ( 2.5 ) 114.5 1.2 60.8 52.5 U.S. government agency securities 3.2 — ( 0.1 ) 3.1 — 1.2 1.9 Certificates of deposit 2.8 — — 2.8 0.8 2.0 — Subtotal 123.0 — ( 2.6 ) 120.4 2.0 64.0 54.4 Total $ 796.7 $ — $ ( 3.2 ) $ 793.5 $ 648.7 $ 77.7 $ 67.1 December 31, 2021 Adjusted Unrealized Unrealized Fair Cash and Short-Term Long-Term Cash and cash equivalents $ 612.3 $ — $ — $ 612.3 $ 612.3 $ — $ — Level 1 (a) : U.S. Treasury securities 26.4 — ( 0.1 ) 26.3 2.0 14.7 9.6 Money market funds 0.9 — — 0.9 0.9 — — Subtotal 27.3 — ( 0.1 ) 27.2 2.9 14.7 9.6 Level 2 (b) : Corporate debt securities 118.9 — ( 0.3 ) 118.6 3.5 66.0 49.1 U.S. government agency securities 4.8 — — 4.8 — 3.5 1.3 Certificates of deposit 1.9 — — 1.9 — 1.9 — Subtotal 125.6 — ( 0.3 ) 125.3 3.5 71.4 50.4 Total $ 765.2 $ — $ ( 0.4 ) $ 764.8 $ 618.7 $ 86.1 $ 60.0 (a) Valuations based on quoted prices for identical assets or liabilities in active markets. (b) 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.
Schedule of Marketable Debt Securities in Continuous Loss Position	The following tables provide information about the Company’s marketable debt securities that have been in a continuous loss position as of September 30, 2022 and December 31, 2021 (in millions, except number of marketable debt securities in a loss position): September 30, 2022 Fair Value of Number of Marketable Unrealized Losses < 12 Months Fair Value of Number of Marketable Unrealized Losses Corporate debt securities $ 103.1 165 $ 2.1 $ 9.2 10 $ 0.5 U.S. Treasury securities 23.0 22 0.4 3.4 6 0.1 U.S. government agency securities 2.9 5 0.1 0.3 1 — Certificates of deposit 0.8 2 — — — — $ 129.8 194 $ 2.6 $ 12.9 17 $ 0.6 December 31, 2021 Fair Value of Number of Marketable Unrealized Corporate debt securities $ 106.9 153 $ 0.3 U.S. Treasury securities 22.4 27 0.1 U.S. government agency securities 4.8 6 — Certificates of deposit 0.5 1 — $ 134.6 187 $ 0.4 (c) For the period ended December 31, 2021, there were no debt securities in a continuous loss position greater than or equal to 12 months.

Employee Benefit Plans and Ot_2

Employee Benefit Plans and Other Postretirement Benefits (Tables)	9 Months Ended
	Sep. 30, 2022
Retirement Benefits [Abstract]
Components of Net Periodic Benefit Costs	The components of net periodic benefit cost for our pension plans were as follows (dollars in millions): Pension Plans Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Service cost $ 4.6 $ 5.4 $ 14.4 $ 16.0 Interest cost 8.6 7.4 26.0 22.2 Expected return on plan assets ( 13.9 ) ( 15.8 ) ( 41.8 ) ( 47.3 ) Net amortization of unrecognized amounts Prior service cost 0.9 1.0 2.7 2.9 Actuarial loss 0.9 2.6 2.6 7.8 Net periodic benefit cost $ 1.1 $ 0.6 $ 3.9 $ 1.6

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement, Noncash Expense [Abstract]
Summary of Restricted Stock and Performance Unit Award Activity	The following table presents restricted stock and performance unit award activity for the nine months ended September 30, 2022: Restricted Stock Performance Units Shares Weighted Shares Weighted Outstanding at January 1, 2022 651,448 $ 109.16 358,092 $ 105.38 Granted 175,047 145.63 133,017 148.71 Vested (a) ( 151,087 ) 115.46 ( 132,404 ) 136.62 Forfeitures ( 14,245 ) 120.47 ( 256 ) 145.26 Outstanding at September 30, 2022 661,163 $ 117.13 358,449 $ 109.89 (a) Upon vesting of the performance unit awards, PCA issued 144,193 shares, which included 11,789 shares for dividends accrued during the vesting period.
Compensation Expense for Share-Based Awards	Our share-based compensation expense is primarily 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): Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Restricted stock $ 4.1 $ 3.9 $ 18.7 $ 18.4 Performance units 3.1 2.9 10.0 8.5 Total share-based compensation expense 7.2 6.8 28.7 26.9 Income tax benefit ( 1.8 ) ( 1.7 ) ( 7.2 ) ( 6.8 ) Share-based compensation expense, net of tax benefit $ 5.4 $ 5.1 $ 21.5 $ 20.1
Unrecognized Compensation Expense for Share-Based Awards	The unrecognized compensation expense for all share-based awards at September 30, 2022 was as follows (dollars in millions): September 30, 2022 Unrecognized Remaining Restricted stock $ 31.4 2.6 Performance units 22.8 2.3 Total unrecognized share-based compensation expense $ 54.2 2.5

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2022
Equity [Abstract]
Components of Changes in Accumulated Other Comprehensive Income (AOCI)	Changes in accumulated other comprehensive income (loss) (AOCI) by component were as follows (dollars in millions). Amounts in parentheses indicate losses: Unrealized Unrealized Loss Unfunded Total Balance at January 1, 2022 $ ( 0.2 ) $ ( 0.2 ) $ ( 74.8 ) $ ( 75.2 ) Other comprehensive income before reclassifications, net of tax — ( 2.1 ) — ( 2.1 ) Amounts reclassified from AOCI, net of tax — — 3.5 3.5 Balance at September 30, 2022 $ ( 0.2 ) $ ( 2.3 ) $ ( 71.3 ) $ ( 73.8 )
Reclassifications Out of Accumulated Other Comprehensive Income (AOCI)	Reclassifications out of AOCI were as follows (dollars in millions). Amounts in parentheses indicate expenses in the Consolidated Statements of Income: Amounts Reclassified from AOCI Three Months Ended September 30, Nine Months Ended September 30, Details about AOCI Components 2022 2021 2022 2021 Unfunded employee benefit obligations (a) Amortization of prior service costs $ ( 0.8 ) $ ( 0.8 ) $ ( 2.4 ) $ ( 2.5 ) See (a) below Amortization of actuarial losses ( 0.8 ) ( 2.5 ) ( 2.3 ) ( 7.5 ) See (a) below ( 1.6 ) ( 3.3 ) ( 4.7 ) ( 10.0 ) Total before tax 0.4 0.8 1.2 2.5 Tax benefit $ ( 1.2 ) $ ( 2.5 ) $ ( 3.5 ) $ ( 7.5 ) Net of tax (a) These AOCI components are included in the computation of net pension and postretirement benefit costs. See Note 14, Employee Benefit Plans and Other Postretirement Benefits, for additional information.

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2022
Segment Reporting [Abstract]
Schedule of Segment Reporting Information by Segment	Selected financial information by reportable segment was as follows (dollars in millions): Sales, net Three Months Ended September 30, 2022 Trade Intersegment Total Operating Income (Loss) Packaging $ 1,935.1 $ 5.1 $ 1,940.2 $ 359.2 (a) Paper 165.3 — 165.3 26.1 (a) Corporate and Other 25.5 37.8 63.3 ( 25.0 ) Intersegment eliminations — ( 42.9 ) ( 42.9 ) — $ 2,125.9 $ — $ 2,125.9 360.3 Non-operating pension income 3.6 Interest expense, net ( 16.5 ) Income before taxes $ 347.4 Sales, net Three Months Ended September 30, 2021 Trade Intersegment Total Operating Income (Loss) Packaging $ 1,825.0 $ 4.4 $ 1,829.4 $ 365.2 (b) Paper 150.3 — 150.3 11.0 (b) Corporate and Other 24.8 36.5 61.3 ( 23.4 ) (b) Intersegment eliminations — ( 40.9 ) ( 40.9 ) — $ 2,000.1 $ — $ 2,000.1 352.8 Non-operating pension income 5.0 Interest expense, net ( 23.9 ) (b) Income before taxes $ 333.9 Sales, net Nine Months Ended September 30, 2022 Trade Intersegment Total Operating Income (Loss) Packaging $ 5,956.8 $ 14.8 $ 5,971.6 $ 1,141.3 (a) Paper 468.6 — 468.6 71.2 (a) Corporate and Other 74.2 110.6 184.8 ( 79.8 ) Intersegment eliminations — ( 125.4 ) ( 125.4 ) — $ 6,499.6 $ — $ 6,499.6 1,132.7 Non-operating pension income 10.9 Interest expense, net ( 55.3 ) Income before taxes $ 1,088.3 Sales, net Nine Months Ended September 30, 2021 Trade Intersegment Total Operating Income (Loss) Packaging $ 5,159.3 $ 12.1 $ 5,171.4 $ 940.3 (b) Paper 457.0 0.1 457.1 22.3 (b) Corporate and Other 70.8 101.0 171.8 ( 76.9 ) (b) Intersegment eliminations — ( 113.2 ) ( 113.2 ) — $ 5,687.1 $ — $ 5,687.1 885.7 Non-operating pension income 14.8 Interest expense, net ( 72.2 ) (b) Income before taxes $ 828.3 (a) The three and nine months ended September 30, 2022 include the following: 1. $ 3.9 million and $ 9.4 million, respectively, of charges related to the announced discontinuation of production of UFS paper grades on the No. 3 machine at the Jackson, Alabama mill associated with the permanent conversion of the machine to produce linerboard and other paper-to-containerboard conversion related activities. 2. $ 0.2 million of charges and $ 0.2 million of income, respectively, consisting of closure costs related to corrugated products facilities and acquisition and integration costs related to the December 2021 Advance Packaging Corporation acquisition, partially offset by a gain on sale of assets related to a corrugated products facility. For the nine months ended September 30, 2022, these costs were offset by insurance proceeds received for a natural disaster at one of the corrugated products facilities and a favorable lease buyout for a closed corrugated products facility. (b) The three and nine months ended September 30, 2021 include the following: 1. $ 4.5 million and $ 9.4 million, respectively, of charges related to the announced discontinuation of production of UFS paper grades on the No. 3 machine at the Jackson, Alabama mill in the first quarter of 2021 associated with the permanent conversion of the machine to produce linerboard and other paper-to-containerboard conversion related activities. 2. $ 2.7 million and $ 0.1 million, respectively, of charges consisting of closure costs related to corrugated products facilities. For the nine months ended September 30, 2021, these costs are partially offset by income primarily consisting of an adjustment of the required asset retirement obligation related to the 2020 closure of the San Lorenzo, California facility, a gain on sale of transportation assets, and insurance proceeds received for a natural disaster at one of the corrugated products facilities. 3. $ 0.5 million of costs related to the Company's September 2021 debt refinancing.

Nature of Operations and Basi_2

Nature of Operations and Basis of Presentation - Additional Information (Details)	9 Months Ended
	Sep. 30, 2022 Segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Date of incorporation	Jan. 25, 1999
Number of reportable segments	3

Acquisitions (Additional Inform

Acquisitions (Additional Information) (Details) - USD ($) $ in Millions		3 Months Ended
	Dec. 11, 2021	Sep. 30, 2022
Maximum
Asset Acquisition [Line Items]
Estimated Useful Lives	P20Y
Minimum
Asset Acquisition [Line Items]
Estimated Useful Lives	P1Y
Advance Packaging Corporation [Member]
Asset Acquisition [Line Items]
Payments to acquire assets	$ 194.9
Weighted average useful life of intangible asset acquired	12 years 9 months 18 days
Decrease in Goodwill		$ 193
Payments for proceeds from seller		$ 1.9
Series of Individually Immaterial Business Acquisitions [Member] | Advance Packaging Corporation [Member]
Asset Acquisition [Line Items]
Business acquisition, effective date of acquisition	Dec. 11, 2021

Acquisitions - Schedule of Tang

Acquisitions - Schedule of Tangible and Intangible Assets Acquired and Liabilities Assumed (Details) - Advance Packaging Corporation [Member] - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Asset Acquisition [Line Items]
Goodwill	$ 59	$ 60
Other intangible assets	48.8	50.2
Property, plant and equipment	67.2	66.7
Other net assets	18	18
Net assets acquired	193	$ 194.9
Adjustment [Member]
Asset Acquisition [Line Items]
Goodwill	(1)
Other intangible assets	(1.4)
Property, plant and equipment	0.5
Other net assets	0
Net assets acquired	$ (1.9)

Revenue - Summary of Revenues D

Revenue - Summary of Revenues Disaggregated by Product Line (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Disaggregation Of Revenue [Line Items]
Revenue	$ 2,125.9	$ 2,000.1	$ 6,499.6	$ 5,687.1
Packaging
Disaggregation Of Revenue [Line Items]
Revenue	1,940.2	1,829.4	5,971.6	5,171.4
Paper
Disaggregation Of Revenue [Line Items]
Revenue	165.3	150.3	468.6	457.1
Corporate and Other
Disaggregation Of Revenue [Line Items]
Revenue	$ 20.4	$ 20.4	$ 59.4	$ 58.6

Revenue - Additional Informatio

Revenue - Additional Information (Details)	9 Months Ended
	Sep. 30, 2022
Packaging Corporation of America
Revenue [Line Items]
Variable interest entity, ownership percentage	50%
Boise Cascade Co-Owner of LTP
Revenue [Line Items]
Variable interest entity, ownership percentage	50%

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		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Numerator:
Net income	$ 262.5	$ 250.7	$ 818.2	$ 624.6
Less: Distributed and undistributed earnings allocated to participating securities	(1.9)	(1.7)	(6.4)	(4.9)
Net income attributable to common shareholders	$ 260.6	$ 249	$ 811.8	$ 619.7
Denominator:
Weighted average basic common shares outstanding (in shares)	92.8	94.3	92.9	94.2
Effect of dilutive securities (in shares)	0.4	0.4	0.4	0.4
Weighted average diluted common shares outstanding (in shares)	93.2	94.7	93.3	94.6
Basic income per common share (in dollars per share)	$ 2.81	$ 2.64	$ 8.74	$ 6.58
Diluted income per common share (in dollars per share)	$ 2.80	$ 2.63	$ 8.70	$ 6.55

Other Expense, Net - Components

Other Expense, Net - Components of Other Income (Expense), Net (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset disposals and write-offs		$ (7.5)	$ (6.4)	$ (33.9)	$ (27.3)
Acquisition-related, facilities closure and other income	[1]	0.2	(0.7)	0.4	2.7
Other		(2.9)	(3.1)	(6.4)	(11)
Total		(12.9)	(13.4)	(44.7)	(41.7)
Jackson, Alabama Mill
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Conversion-related activities	[2]	$ (2.7)	$ (3.2)	$ (4.8)	$ (6.1)
[1] For the three months ended September 30, 2022, includes income consisting of a gain on sale of assets related to a corrugated products facility, partially offset by charges consisting of closure costs related to corrugated products facilities. For the nine months ended September 30, 2022, includes income primarily related to insurance proceeds received for a natural disaster at one of the corrugated products facilities and a gain on sale of assets related to a corrugated products facility, partially offset by closure costs related to corrugated products facilities and acquisition and integration costs related to the December 2021 Advance Packaging acquisition. For the three months ended September 30, 2021, includes charges consisting of closure costs related to corrugated products facilities. For the nine months ended September 30, 2021, includes income primarily related to an adjustment of the required asset retirement obligation related to the 2020 closure of the San Lorenzo, California facility, a gain on sale of transportation assets, and insurance proceeds received for a natural disaster at one of the corrugated products facilities, partially offset by closure costs related to corrugated products facilities. Includes charges related to the announced discontinuation of production of uncoated freesheet paper grades on the No. 3 machine at the Jackson, Alabama mill in the first quarter of 2021 associated with the permanent conversion of the machine to produce linerboard and other paper-to-containerboard conversion related activities.

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income tax provision	$ 84.9	$ 83.2	$ 270.1	$ 203.7
Effective income tax rate, percent	24.40%	24.90%	24.80%	24.60%
Federal statutory income tax rate			21%
Cash paid for taxes, net of refunds received			$ 221.6	$ 168.1

Inventories - Components of Inv

Inventories - Components of Inventories (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Inventory Disclosure [Abstract]
Raw materials	$ 381.3	$ 324.2
Work in process	16	16.2
Finished goods	195	201
Supplies and materials	402.6	361.1
Inventories	$ 994.9	$ 902.5

Property, Plant, and Equipmen_2

Property, Plant, and Equipment - Components of Property, Plant, and Equipment (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Property, Plant, And Equipment [Line Items]
Property, plant and equipment, at cost	$ 8,387	$ 7,871.5
Less accumulated depreciation	(4,573.8)	(4,342.5)
Property, plant, and equipment, net	3,813.2	3,529
Land and Land Improvements
Property, Plant, And Equipment [Line Items]
Property, plant and equipment, at cost	193	189.8
Buildings
Property, Plant, And Equipment [Line Items]
Property, plant and equipment, at cost	1,006.6	938.7
Machinery and Equipment
Property, Plant, And Equipment [Line Items]
Property, plant and equipment, at cost	6,452.3	6,159.1
Construction in Progress
Property, Plant, And Equipment [Line Items]
Property, plant and equipment, at cost	608.4	481
Other
Property, Plant, And Equipment [Line Items]
Property, plant and equipment, at cost	$ 126.7	$ 102.9

Property, Plant, and Equipmen_3

Property, Plant, and Equipment - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Depreciation [Abstract]
Depreciation expense	$ 103.2	$ 95.5	$ 305.3	$ 279.9
Incremental depreciation			3.1	$ 3.6
Purchases of property, plant, and equipment included in accounts payable			$ 91.4		$ 73.6

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets -Goodwill - (Details) $ in Millions	9 Months Ended
	Sep. 30, 2022 USD ($)
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 923.5
Adjustment related to sale of corrugated assets	(0.1)	[1]
Goodwill, Ending Balance	922.4
Advance Packaging Corporation [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	923.5
Acquisitions	(1)	[2]
Goodwill, Ending Balance	$ 1
[1] During the three months ended September 30, 2022, a corrugated products facility sold part of its operations, which primarily included existing inventory. As a result, the Company recorded a $ 0.1 million adjustment to decrease the goodwill balance During the nine months ended September 30, 2022, the Company recorded a $ 1.0 million adjustment to decrease the goodwill balance for the Company's December 2021 acquisition of Advance Packaging.

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Goodwill (Parenthetical) (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Goodwill [Line Items]
Goodwill	$ 922.4	$ 923.5
Corrugated Products Facilities
Goodwill [Line Items]
Goodwill	0.1
Advance Packaging Corporation [Member]
Goodwill [Line Items]
Goodwill	$ 1	$ 923.5

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Components of Intangible Assets (Details) - USD ($) $ in Millions		9 Months Ended	12 Months Ended
		Sep. 30, 2022	Dec. 31, 2021
Finite Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in Years)		8 years 4 months 24 days	8 years 6 months
Gross Carrying Amount		$ 591.8	$ 593.1
Accumulated Amortization		$ 314.4	$ 284.7
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in Years)	[1]	8 years 4 months 24 days	8 years 6 months
Gross Carrying Amount	[1]	$ 546	$ 551.1
Accumulated Amortization	[1]	$ 282	$ 254.9
Trademarks and Trade Names
Finite Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in Years)	[1]	7 years 4 months 24 days	8 years 4 months 24 days
Gross Carrying Amount	[1]	$ 41.3	$ 37.6
Accumulated Amortization	[1]	$ 28	$ 25.5
Other Intangible Assets
Finite Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in Years)	[1]	3 years 7 months 6 days	2 years 2 months 12 days
Gross Carrying Amount	[1]	$ 4.5	$ 4.4
Accumulated Amortization	[1]	$ 4.4	$ 4.3
[1] In connection with the December 2021 acquisition of Advance Packaging, the Company recorded intangible assets of $ 47.3 million for customer relationships, $ 2.8 million for trade names, and $ 0.1 million for other intangibles. During the three months ended June 30, 2022, the Company made a $ 1.4 million net adjustment based on the final valuation received for the intangible assets. This adjustment resulted in a revision to the original allocations for customer relationships and trade names. As of June 30, 2022, the revised allocations for customer relationships and trade names were $ 42.2 million and $ 6.5 million, respectively.

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Components of Intangible Assets (Parenthetical) (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Adjustments to intangible assets valuation	$ 1.4
Advance Packaging Corporation [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets	42.2	$ 47.3
Trade Names	$ 6.5	2.8
Other intangibles		$ 0.1

Goodwill and Intangible Asset_6

Goodwill and Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Jun. 30, 2022	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Adjustment to decrease the remaining book value of intangible asset	$ 1.4
Amortization expense		$ 29.7	$ 28.2
Goodwill		$ 922.4		$ 923.5

Accrued Liabilities - Component

Accrued Liabilities - Components of Accrued Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Accrued Liabilities, Current [Abstract]
Compensation and benefits	$ 146.5	$ 157.1
Customer rebates and other credits	40.3	36.9
Franchise, property, sales and use taxes	29	17.6
Medical insurance and workers’ compensation	25.9	26.9
Environmental liabilities and asset retirement obligations	3.8	4
Severance, retention, and relocation	1.9	2.7
Other	12.1	9.8
Total	$ 259.5	$ 255

Debt - Additional Information (

Debt - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Debt Instrument [Line Items]
Cash payments paid for interest			$ 50.6	$ 55.2
Amortization of financing costs	$ 0.4	$ 0.5	1.2	$ 1.5
Senior Notes | Fixed-Rate Senior Notes
Debt Instrument [Line Items]
Book value of fixed rate debt	2,491.4		2,491.4
Long-term debt (fixed-rate debt), fair value	$ 2,004.1		$ 2,004.1

Cash, Cash Equivalents, and M_3

Cash, Cash Equivalents, and Marketable Debt Securities - Schedule of Company's Cash and Available-For-Sale (AFS) Debt Securities by Major Asset Category (Details) - USD ($) $ in Millions		9 Months Ended		12 Months Ended
		Sep. 30, 2022		Dec. 31, 2021
Financial Instruments [Line Items]
Adjusted Cost Basis		$ 796.7		$ 765.2
Unrealized Gain		0		0
Unrealized Loss		(3.2)		(0.4)
Fair Value		793.5		764.8
Cash and cash equivalents		648.7		618.7
Short-term marketable debt securities		77.7		86.1
Long-term marketable debt securities		67.1		60
Level 1
Financial Instruments [Line Items]
Adjusted Cost Basis		30.7		27.3
Unrealized Gain		0		0
Unrealized Loss		(0.6)		(0.1)
Fair Value		30.1		27.2
Cash and cash equivalents		3.7		2.9
Short-term marketable debt securities		13.7		14.7
Long-term marketable debt securities		12.7		9.6
Level 2
Financial Instruments [Line Items]
Adjusted Cost Basis		123		125.6
Unrealized Gain		0		0
Unrealized Loss		(2.6)		(0.3)
Fair Value		120.4		125.3
Cash and cash equivalents		2		3.5
Short-term marketable debt securities		64		71.4
Long-term marketable debt securities		54.4		50.4
U.S. Government Agency Securities | Level 2
Financial Instruments [Line Items]
Adjusted Cost Basis		3.2	[1]	4.8	[2]
Unrealized Gain		0		0
Unrealized Loss		(0.1)		0
Fair Value	[1]	3.1		4.8
Cash and cash equivalents		0		0
Short-term marketable debt securities	[1]	1.2		3.5
Long-term marketable debt securities	[1]	1.9		1.3
Corporate Debt Securities | Level 2
Financial Instruments [Line Items]
Adjusted Cost Basis		117	[1]	118.9	[2]
Unrealized Gain		0		0
Unrealized Loss	[1]	(2.5)		(0.3)
Fair Value	[1]	114.5		118.6
Cash and cash equivalents	[1]	1.2		3.5
Short-term marketable debt securities	[1]	60.8		66
Long-term marketable debt securities	[1]	52.5		49.1
Cash and Cash Equivalents
Financial Instruments [Line Items]
Adjusted Cost Basis		643		612.3
Unrealized Gain		0		0
Unrealized Loss		0		0
Fair Value		643		612.3
Cash and cash equivalents		643		612.3
Short-term marketable debt securities		0		0
Long-term marketable debt securities		0		0
Money Market Fund | Level 1
Financial Instruments [Line Items]
Adjusted Cost Basis	[2]	0.7		0.9
Unrealized Gain		0	[2]	0
Unrealized Loss		0		0
Fair Value	[2]	0.7		0.9
Cash and cash equivalents	[2]	0.7		0.9
Short-term marketable debt securities		0		0
Long-term marketable debt securities		0		0
U.S. Treasury Securities | Level 1
Financial Instruments [Line Items]
Adjusted Cost Basis	[2]	30		26.4
Unrealized Gain		0	[2]	0
Unrealized Loss	[2]	(0.6)		(0.1)
Fair Value	[2]	29.4		26.3
Cash and cash equivalents	[2]	3		2
Short-term marketable debt securities	[2]	13.7		14.7
Long-term marketable debt securities	[2]	12.7		9.6
Certificates of Deposit | Level 2
Financial Instruments [Line Items]
Adjusted Cost Basis		2.8	[1]	1.9	[2]
Unrealized Gain		0		0
Unrealized Loss		0		0
Fair Value	[1]	2.8		1.9
Cash and cash equivalents		0.8	[1]	0
Short-term marketable debt securities	[1]	2		1.9
Long-term marketable debt securities		$ 0		$ 0
[1] 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. Valuations based on quoted prices for identical assets or liabilities in active markets.

Cash, Cash Equivalents, and M_4

Cash, Cash Equivalents, and Marketable Debt Securities - Additional Information (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Financial Instruments [Line Items]
Impairment of marketable debt securities	$ 0	$ 0
Allowance for credit loss	$ 0	$ 0
Minimum
Financial Instruments [Line Items]
Long-term marketable debt securities maturity period	1 year
Maximum
Financial Instruments [Line Items]
Long-term marketable debt securities maturity period	2 years

Cash, Cash Equivalents, and M_5

Cash, Cash Equivalents, and Marketable Debt Securities - Schedule of Marketable Debt Securities in Continuous Loss Position (Details) $ in Millions		Sep. 30, 2022 USD ($) Security	Dec. 31, 2021 USD ($) Security
Schedule Of Available For Sale Securities [Line Items]
Fair Value of Marketable Debt Securities			$ 134.6
Number of Marketable Debt Securities in a Loss Position | Security			187
Unrealized Losses	[1]		$ 0.4
Fair Value of Marketable Debt Securities in a Loss Position Less Than 12 Months		$ 129.8
Unrealized Losses Less Than 12 Months		$ 2.6
Number of Marketable Debt Securities in a Loss Position Less Than 12 Months | Security		194
Fair Value of Marketable Debt Securities in a Loss Position 12 Months Or Longer		$ 12.9
Unrealized Losses 12 Months Or Longer		$ 0.6
Fair Value of Marketable Debt Securities in a Loss Position 12 Months Or Longer | Security		17
U.S. Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Fair Value of Marketable Debt Securities			$ 22.4
Number of Marketable Debt Securities in a Loss Position | Security			27
Unrealized Losses	[1]		$ 0.1
Fair Value of Marketable Debt Securities in a Loss Position Less Than 12 Months		$ 23
Unrealized Losses Less Than 12 Months		$ 0.4
Number of Marketable Debt Securities in a Loss Position Less Than 12 Months | Security		22
Fair Value of Marketable Debt Securities in a Loss Position 12 Months Or Longer		$ 3.4
Unrealized Losses 12 Months Or Longer		$ 0.1
Fair Value of Marketable Debt Securities in a Loss Position 12 Months Or Longer | Security		6
Certificates of Deposit
Schedule Of Available For Sale Securities [Line Items]
Fair Value of Marketable Debt Securities			$ 0.5
Number of Marketable Debt Securities in a Loss Position | Security			1
Unrealized Losses			$ 0
Fair Value of Marketable Debt Securities in a Loss Position Less Than 12 Months		$ 0.8
Unrealized Losses Less Than 12 Months		$ 0
Number of Marketable Debt Securities in a Loss Position Less Than 12 Months | Security		2
Fair Value of Marketable Debt Securities in a Loss Position 12 Months Or Longer		$ 0
Unrealized Losses 12 Months Or Longer		$ 0
Fair Value of Marketable Debt Securities in a Loss Position 12 Months Or Longer | Security		0
Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Fair Value of Marketable Debt Securities			$ 106.9
Number of Marketable Debt Securities in a Loss Position | Security			153
Unrealized Losses	[1]		$ 0.3
Fair Value of Marketable Debt Securities in a Loss Position Less Than 12 Months		$ 103.1
Unrealized Losses Less Than 12 Months		$ 2.1
Number of Marketable Debt Securities in a Loss Position Less Than 12 Months | Security		165
Fair Value of Marketable Debt Securities in a Loss Position 12 Months Or Longer		$ 9.2
Unrealized Losses 12 Months Or Longer		$ 0.5
Fair Value of Marketable Debt Securities in a Loss Position 12 Months Or Longer | Security		10
U.S. Government Agency Securities
Schedule Of Available For Sale Securities [Line Items]
Fair Value of Marketable Debt Securities			$ 4.8
Number of Marketable Debt Securities in a Loss Position | Security			6
Unrealized Losses
Fair Value of Marketable Debt Securities in a Loss Position Less Than 12 Months		$ 2.9
Unrealized Losses Less Than 12 Months		$ 0.1
Number of Marketable Debt Securities in a Loss Position Less Than 12 Months | Security		5
Fair Value of Marketable Debt Securities in a Loss Position 12 Months Or Longer		$ 0.3
Unrealized Losses 12 Months Or Longer		$ 0
Fair Value of Marketable Debt Securities in a Loss Position 12 Months Or Longer | Security		1
[1] For the period ended December 31, 2021, there were no debt securities in a continuous loss position greater than or equal to 12 months.

Employee Benefit Plans and Ot_3

Employee Benefit Plans and Other Postretirement Benefits - Components of Net Periodic Benefit Costs (Details) - Pension Plans - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4.6	$ 5.4	$ 14.4	$ 16
Interest cost	8.6	7.4	26	22.2
Expected return on plan assets	(13.9)	(15.8)	(41.8)	(47.3)
Net amortization of unrecognized amounts, Prior service cost	0.9	1	2.7	2.9
Net amortization of unrecognized amounts, Actuarial loss	0.9	2.6	2.6	7.8
Net periodic benefit cost	$ 1.1	$ 0.6	$ 3.9	$ 1.6

Employee Benefit Plans and Ot_4

Employee Benefit Plans and Other Postretirement Benefits - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2022
Pension Contributions [Abstract]
Contributions to pension plan	$ 50	$ 50
Pension Plans | Qualified Plan
Pension Contributions [Abstract]
Contributions to pension plan		$ 0

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) - shares shares in Millions	9 Months Ended
	Sep. 30, 2022	May 05, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Long-term equity incentive plan, termination date	May 05, 2030
Number of shares available for future issuance under share-based plan	1	1.4
Number of shares authorized under plan	12
Performance Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of ROIC as performance measure	50%
Percentage of TSR as performance measure	50%

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Restricted Stock and Performance Unit Award Activity (Details)	9 Months Ended
	Sep. 30, 2022 $ / shares shares
Restricted Stock
Restricted Stock and Performance Units [Roll Forward]
Outstanding at January 1, 2022 | shares	651,448
Granted | shares	175,047
Vested | shares	(151,087)
Forfeitures | shares	(14,245)
Outstanding at June 30, 2022 | shares	661,163
Restricted Stock and Performance Units (Weighted Average Grant-date Fair Value) [Abstract]
Weighted Average Grant-Date Fair Value, Outstanding at January 1, 2022 | $ / shares	$ 109.16
Weighted Average Grant-Date Fair Value, Granted | $ / shares	145.63
Weighted Average Grant-Date Fair Value, Vested | $ / shares	115.46
Weighted Average Grant-Date Fair Value, Forfeitures | $ / shares	120.47
Weighted Average Grant-Date Fair Value, Outstanding at June 30, 2022 | $ / shares	$ 117.13
Performance Units
Restricted Stock and Performance Units [Roll Forward]
Outstanding at January 1, 2022 | shares	358,092
Granted | shares	133,017
Vested | shares	(132,404)
Forfeitures | shares	(256)
Outstanding at June 30, 2022 | shares	358,449
Restricted Stock and Performance Units (Weighted Average Grant-date Fair Value) [Abstract]
Weighted Average Grant-Date Fair Value, Outstanding at January 1, 2022 | $ / shares	$ 105.38
Weighted Average Grant-Date Fair Value, Granted | $ / shares	148.71
Weighted Average Grant-Date Fair Value, Vested | $ / shares	136.62
Weighted Average Grant-Date Fair Value, Forfeitures | $ / shares	145.26
Weighted Average Grant-Date Fair Value, Outstanding at June 30, 2022 | $ / shares	$ 109.89

Share-Based Compensation - Su_2

Share-Based Compensation - Summary of Restricted Stock and Performance Unit Award Activity (Parenthetical) (Details) - Performance Units	9 Months Ended
	Sep. 30, 2022 shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock Issued During Period, Shares, Restricted Stock Award, Gross	144,193,000
Shares issued on accrued dividends	11,789,000

Share-Based Compensation - Comp

Share-Based Compensation - Compensation Expense for Share-Based Awards (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 7.2	$ 6.8	$ 28.7	$ 26.9
Income tax benefit	(1.8)	(1.7)	(7.2)	(6.8)
Share-based compensation expense, net of tax benefit	5.4	5.1	21.5	20.1
Restricted Stock
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	4.1	3.9	18.7	18.4
Performance Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 3.1	$ 2.9	$ 10	$ 8.5

Share-Based Compensation - Unre

Share-Based Compensation - Unrecognized Compensation Expense for Share-Based Awards (Details) $ in Millions	9 Months Ended
	Sep. 30, 2022 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 54.2
Remaining weighted-average recognition period	2 years 6 months
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 31.4
Remaining weighted-average recognition period	2 years 7 months 6 days
Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 22.8
Remaining weighted-average recognition period	2 years 3 months 18 days

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended	9 Months Ended
	Oct. 17, 2022	May 17, 2022	Sep. 30, 2022	Sep. 30, 2022	Sep. 30, 2021	Jan. 26, 2022
Common stock dividends paid				$ 304.4	$ 284.8
Dividends paid per common share (in dollars per share)		$ 1.25
Stock repurchase program, authorized amount						$ 1,000
Repurchases of common stock under stock repurchase program			1,000,000	858,000
Common stock repurchase authorization amount available			$ 142	$ 142
Subsequent Events
Common stock dividends paid	$ 115.9
Maximum
Dividends paid per common share (in dollars per share)		5
Minimum
Dividends paid per common share (in dollars per share)		$ 4

Stockholders' Equity - Changes

Stockholders' Equity - Changes in Accumulated Other Comprehensive Income by Component (Details) $ in Millions	9 Months Ended
	Sep. 30, 2022 USD ($)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 3,607.2
Ending balance	3,971.2
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(0.2)
Other comprehensive income before reclassifications, net of tax	0
Amounts reclassified from AOCI, net of tax	0
Ending balance	(0.2)
Unfunded Employee Benefit Obligations
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(75.2)
Other comprehensive income before reclassifications, net of tax	(2.1)
Amounts reclassified from AOCI, net of tax	3.5
Ending balance	(73.8)
Foreign Exchange Contract | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(0.2)
Other comprehensive income before reclassifications, net of tax	(2.1)
Amounts reclassified from AOCI, net of tax	0
Ending balance	(2.3)
Marketable Debt Securities | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(74.8)
Other comprehensive income before reclassifications, net of tax	0
Amounts reclassified from AOCI, net of tax	3.5
Ending balance	$ (71.3)

Stockholders' Equity - Reclassi

Stockholders' Equity - Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Income before taxes		$ 347.4	$ 333.9	$ 1,088.3	$ 828.3
Income tax benefit		(84.9)	(83.2)	(270.1)	(203.7)
Net income		262.5	250.7	818.2	624.6
Unfunded Employee Benefit Obligations | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amortization of prior service costs	[1]	(0.8)	(0.8)	(2.4)	(2.5)
Amortization of actuarial losses	[1]	(0.8)	(2.5)	(2.3)	(7.5)
Income before taxes		(1.6)	(3.3)	(4.7)	(10)
Income tax benefit		0.4	0.8	1.2	2.5
Net income		$ (1.2)	$ (2.5)	$ (3.5)	$ (7.5)
[1] These AOCI components are included in the computation of net pension and postretirement benefit costs. See Note 14, Employee Benefit Plans and Other Postretirement Benefits, for additional information.

Concentrations of Risk - Additi

Concentrations of Risk - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Concentration Risk [Line Items]
Accounts receivable, net, current	$ 1,112.8		$ 1,071
Office Depot | Credit Concentration Risk
Concentration Risk [Line Items]
Accounts receivable, net, current	$ 43.5		$ 49.8
Office Depot | Total Company Sales Revenue | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	4%	4%
Office Depot | Total Company Receivables | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage			4%
Paper | Office Depot | Paper Segment Sales Revenue | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	50%	48%	51%

Transactions With Related Par_2

Transactions With Related Parties - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Related Party Transaction [Line Items]
Carrying amount of LTP's assets	$ 8,344.4		$ 8,344.4		$ 7,836.8
Boise Cascade Co-Owner of LTP
Related Party Transaction [Line Items]
Variable interest entity, ownership percentage			50%
Boise Cascade Co-Owner of LTP | Fiber
Related Party Transaction [Line Items]
Revenue from related parties	23.1	$ 22.3	$ 67.4	$ 63.3
Boise Cascade Co-Owner of LTP | Wood Products, Including Chips and Logs
Related Party Transaction [Line Items]
Fiber costs from related parties	3.4	$ 3.6	$ 10.7	$ 10.3
Packaging Corporation of America
Related Party Transaction [Line Items]
Variable interest entity, ownership percentage			50%
Variable Interest Entity
Related Party Transaction [Line Items]
Carrying amount of LTP's assets	$ 4.1		$ 4.1		$ 3.5

Segment Information - Additiona

Segment Information - Additional Information (Details)	9 Months Ended
	Sep. 30, 2022 Segment
Segment Reporting [Abstract]
Number of reportable segments	3

Segment Information - Selected

Segment Information - Selected Financial Information by Reportable Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
Net sales	$ 2,125.9	$ 2,000.1	$ 6,499.6	$ 5,687.1
Operating Income (Loss)	360.3	352.8	1,132.7	885.7
Non-operating pension income	3.6	5	10.9	14.8
Interest expense, net	(16.5)	(23.9)	(55.3)	(72.2)
Income before taxes	347.4	333.9	1,088.3	828.3
Trade
Segment Reporting Information [Line Items]
Net sales	2,125.9	2,000.1	6,499.6	5,687.1
Intersegment Eliminations
Segment Reporting Information [Line Items]
Net sales	(42.9)	(40.9)	(125.4)	(113.2)
Operating Segments
Segment Reporting Information [Line Items]
Net sales	2,125.9	2,000.1	6,499.6	5,687.1
Segment Reconciling Items
Segment Reporting Information [Line Items]
Net sales	(42.9)	(40.9)	(125.4)	(113.2)
Packaging
Segment Reporting Information [Line Items]
Net sales	1,940.2	1,829.4	5,971.6	5,171.4
Operating Income (Loss)	359.2	365.2	1,141.3	940.3
Packaging | Trade
Segment Reporting Information [Line Items]
Net sales	1,935.1	1,825	5,956.8	5,159.3
Packaging | Intersegment Eliminations
Segment Reporting Information [Line Items]
Net sales	5.1	4.4	14.8	12.1
Packaging | Operating Segments
Segment Reporting Information [Line Items]
Net sales	1,940.2	1,829.4	5,971.6	5,171.4
Paper
Segment Reporting Information [Line Items]
Net sales	165.3	150.3	468.6	457.1
Operating Income (Loss)	26.1	11	71.2	22.3
Paper | Trade
Segment Reporting Information [Line Items]
Net sales	165.3	150.3	468.6	457
Paper | Intersegment Eliminations
Segment Reporting Information [Line Items]
Net sales			0	0.1
Paper | Operating Segments
Segment Reporting Information [Line Items]
Net sales	165.3	150.3	468.6	457.1
Corporate and Other
Segment Reporting Information [Line Items]
Net sales	20.4	20.4	59.4	58.6
Operating Income (Loss)	(25)	(23.4)	(79.8)	(76.9)
Corporate and Other | Trade
Segment Reporting Information [Line Items]
Net sales	25.5	24.8	74.2	70.8
Corporate and Other | Intersegment Eliminations
Segment Reporting Information [Line Items]
Net sales	37.8	36.5	110.6	101
Corporate and Other | Operating Segments
Segment Reporting Information [Line Items]
Net sales	$ 63.3	$ 61.3	184.8	$ 171.8
Intersegment
Segment Reporting Information [Line Items]
Net sales			$ 0

Segment Information - Selecte_2

Segment Information - Selected Financial Information by Reportable Segment (Parenthetical) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
Debt Refinancing Cost				$ 0.5
Packaging and Paper
Segment Reporting Information [Line Items]
Restructuring charges	$ 0.2	$ 2.7	$ 0.2	0.1
Jackson, Alabama Mill | Corrugated Products Facilities
Segment Reporting Information [Line Items]
Adjustment of asset retirement obligation	$ 3.9	$ 4.5	$ 9.4	$ 9.4

Commitments, Guarantees, Inde_2

Commitments, Guarantees, Indemnifications, and Legal Proceedings - Additional Information (Details) - DeRidder, Louisiana - USD ($)	3 Months Ended	9 Months Ended
	Jun. 30, 2018	Sep. 30, 2022	Feb. 08, 2017
Schedule Of Commitments And Contingencies [Line Items]
Loss contingency, period of occurrence		February 8, 2017
Liability insurance			$ 1,000,000
Payment of penalties	$ 40,000
Payment of civil penalty		$ 2,500,000