Basis of Presentation (Policies)	3 Months Ended
Basis of Presentation (Policies)	Mar. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The unaudited consolidated financial statements and notes thereto of the Company have been prepared in accordance with GAAP for interim financial information and in accordance with the rules and regulations of the SEC. In the opinion of management, these consolidated financial statements and notes reflect all adjustments, including all normal recurring adjustments, necessary for a fair presentation of the results of operations, financial position and cash flows for the periods presented. These statements and notes should be read in conjunction with the consolidated financial statements and supplementary data included in the Company’s 2023 Form 10-K.
Change in Accounting Policy	Change in Accounting Policy On January 1, 2024, the Company changed the method of valuation of its finished goods, work-in-process and raw materials inventories from first-in first-out to average cost. The Company believes the average cost method is preferable because it provides better matching of revenue and expense trends and is a better reflection of periodic income from operations. This change was not retrospectively applied to prior periods presented, as the overall effect of the change is not deemed material to the Company’s consolidated financial statements.
Accounting Pronouncements	Accounting Pronouncements There have been no new or recently adopted accounting pronouncements impacting the Company’s consolidated interim financial statements. The Company continues to evaluate the impacts of ASU 2023-05 “Business Combinations—Joint Venture Formations (Subtopic 805-60): Recognition and Initial Measurement,” ASU 2023-07 “Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures” and ASU 2023-09 “Income Taxes (Topic 740): Improvements to Income Tax Disclosures” as previously disclosed in its 2023 Form 10-K.
Subsequent Events	Subsequent Events Indefinite Suspension of Operations of Temiscaming High Purity Cellulose Plant On April 29, 2024, the Company announced that it will suspend operations at its Temiscaming High Purity Cellulose plant, effective July 2, 2024, for an indefinite period. The decision does not affect the Temiscaming paperboard and high-yield pulp plants that support the Company’s High-Yield Pulp and Paperboard operating segments, which will continue to operate at full capacity while remaining part of an ongoing, previously announced, sales process. The effective date was determined as the latest possible date allowing enough lead time for the Company to properly execute the shutdown prior to the arrival of winter in the region. The High Purity Cellulose plant will be idled in a safe and environmentally sound manner. The Company will assess on an annual basis the possibility of restarting the Temiscaming High Purity Cellulose plant. The indefinite suspension of operations will result in approximately 275 layoffs. In connection with the suspension of operations, the Company expects to incur one-time operating charges in 2024 of approximately $30 million, including mothball, severance and other employee costs. Further, the Company also expects to incur non-cash charges in 2024 related to impairments, the amounts of which will be assessed. While most 2024 cash costs associated with the suspension of operations will be incurred and paid in the third and fourth quarters, severance and other restructuring costs are expected to be paid over a period of time. From 2021 through 2023, average maintenance capital expenditures for the Temiscaming High Purity Cellulose plant was $15 million. In 2023, the High Purity Cellulose plant incurred an operating loss of $60 million, including a non-cash asset impairment of $25 million. Working capital for the High Purity Cellulose plant was $31 million at the end of 2023. Sale of Softwood Lumber Duty Rights In August 2021, the Company completed the sale of its lumber and newsprint facilities. As part of the sale, the Company retained all refund rights, including interest, to softwood lumber duties paid by the Company from 2017 through 2021, and has accumulated a $40 million receivable as a result of USDOC administrative reviews. On May 6, 2024, the Company announced the sale of these rights, including all accrued interest, for $39 million, with the opportunity for additional sale proceeds in the future contingent upon the timing and terms of the ultimate outcome of the trade dispute between the USDOC and Canada.
Financial Instruments	The carrying amounts of the Company’s cash, receivables and payables approximate fair value due to the short-term nature of those instruments. The carrying amount of borrowings outstanding under the ABL Credit Facility, 2027 Term Loan and short-term factoring facility approximate fair value due to their variable interest rates.