Basis of Presentation and Significant Accounting Policies - Additional Information (Details) - USD ($)			3 Months Ended
	Sep. 12, 2023	Dec. 01, 2022	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2023
Basis of Presentation and Significant Accounting Policies [Line Items]
Common Stock, Par or Stated Value Per Share			$ 0.01		$ 0.01
Gain (loss) on sale of businesses				$ 11,100,000
Supplier Finance Program Obligation [Member]
Basis of Presentation and Significant Accounting Policies [Line Items]
Outstanding payment obligations to financial institutions			$ 436,100,000		$ 425,800,000
Eaton, IN, and Aurora, IL [Member]
Basis of Presentation and Significant Accounting Policies [Line Items]
Sale of uncoated recycled paperboard mills subject to working capital adjustment		$ 50,000,000
Sale proceeds received		25,000,000
Preliminary working capital settlement		900,000
Amount financed		25,000,000
Gain (loss) on sale of businesses		$ 11,100,000
Transaction Agreement with Smurfit Kappa [Member]
Basis of Presentation and Significant Accounting Policies [Line Items]
Transaction agreement conditions description			The Transaction is subject to certain conditions set forth in the Transaction Agreement, including, but not limited to: certain regulatory clearances, approval by the shareholders and stockholders of both companies (the approval of the Scheme by 75% or more in value of the Smurfit Kappa Shares held by such shareholders of Smurfit Kappa that are present and voting at the Court Meeting (as defined in the Transaction Agreement), and the affirmative vote of the holders of a majority of the outstanding shares of Company Common Stock), the registration statement for the offer of ListCo Shares being declared effective by the SEC and the approval of the ListCo Shares for listing on the NYSE.
Agreement termination fee payable if breaches non-solicitation covenant	$ 147,000,000
Agreement termination fee payable if stockholder approval failure	57,000,000
Common Stock [Member] | Transaction Agreement with Smurfit Kappa [Member]
Basis of Presentation and Significant Accounting Policies [Line Items]
Amount in excess of one share of stock	$ 5
Conversion of stock, Shares	1
Common Stock, Par or Stated Value Per Share	$ 0.01
Mexico Acquisition [Member]
Basis of Presentation and Significant Accounting Policies [Line Items]
Date of acquisition		Dec. 01, 2022
Percentage of remaining interest acquired		67.70%
Cash payment to acquire businesses		$ 969,800,000
Accounting Standards Update 2022-04 [Member]
Basis of Presentation and Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted			true
Change in accounting principle, accounting standards update, adoption date			Oct. 01, 2023
Change in accounting principle, accounting standards update, immaterial effect			true
Accounting Standards Update 2022-01 [Member]
Basis of Presentation and Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted			true
Change in accounting principle, accounting standards update, adoption date			Oct. 01, 2023
Change in accounting principle, accounting standards update, immaterial effect			true