(Restructuring and Related Costs Tables) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net									$ 195	$ 57		$ 29
Overhead cost reduction initiative
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net						$ 21				21	[1]
EMEA packaging restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net					$ 17					15	[2]	47	[3]
Early debt extinguishment costs (see Note 16)
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net	$ 65	$ 105	$ 18	$ 8	21				196	$ 21		10
Gain on sale of investment in Liaison Technologies Inc.
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net												(31)
Riverdale mill conversion severance
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net				$ 1	$ 2	$ 1	$ 1	$ 1				$ 3
Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net									$ (1)

[1] Includes pre-tax charges of $11 million, $6 million and $4 million in Corporate, the Printing Papers segment and the Global Cellulose Fibers segment, respectively, for severance related to an overhead cost reduction initiative. The majority of the severance charges were paid in 2020.

[2] Includes $14 million of severance and $1 million in other charges in conjunction with the restructuring of our EMEA Packaging business. The majority of the severance charges were paid in 2020.

[3] Includes $33 million of severance, $6 million in accelerated depreciation, $2 million in accelerated amortization and $6 million in other charges in conjunction with the optimization of our EMEA Packaging business. The majority of the severance charges recorded were paid throughout 2018.