Related Party Transactions (Details) - NACP Combination - International Paper Company - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Transition Services
Related Party Transaction [Line Items]
Payments to suppliers	$ 0.1	$ 7.5
Fiber Procurement And Corrugated Products
Related Party Transaction [Line Items]
Payments to suppliers	2.8	3.0
Wood
Related Party Transaction [Line Items]
Payments to suppliers	62.0	47.0
Ink Supply
Related Party Transaction [Line Items]
Payments to suppliers	6.3	7.4
Unrelated To Agreements
Related Party Transaction [Line Items]
Payments to suppliers	$ 0.6	$ 3.0

Payments of cash to suppliers for goods and services during the current period.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 17
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3367-108585

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 17
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3367-108585

Name:	us-gaap_PaymentsToSuppliers
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration