Interim Financial Results (Footnotes) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill, Impairment Loss									$ 60
Selling and administrative expenses							$ 12		1,647		$ 1,723		$ 1,621
Litigation settlement recovery					$ (5)
Litigation reserves	$ 19	$ 22
Litigation settlement		32						$ 9	32		0		354
Environmental remediation reserve adjustment	10	15				$ 9
(Gain) loss on transfer of business	1	(9)		$ (7)					0		488		0
Restructuring and other charges, net									57		29		67
Multi-employer pension plan exit liability		(7)		16
Abandoned property removal	15	13	$ 11	11	8	6	9	9
Value added tax receivable	(6)								(6)
Corporate special items	3		1						104	[1]	9	[1]	76	[1]
Brazil Packaging impairment						122					122
Non-operating pension expense	9	9	8	10	429	25	36	4	36		494		530
Non-operating pension expense (income)													484
Pre-tax charges (gains)	145	105	173	31	414	167	83	44
U.S. federal tax rate change			9						0		(13)		(1,451)
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount			(3)				9
Effective Income Tax Rate Reconciliation, Tax Settlement, Foreign, Amount			3		25
Internal investment restructuring	(53)				19
Foreign valuation allowance	203								203		0		0
Tax impact of other special items	(28)	(14)	(5)	(6)	3	(46)	(13)	(9)
Tax impact of non-operating pension expense	(2)	(2)	(2)	(2)	(107)	(6)	(9)	(1)
Other Tax Expense (Benefit)	120	(16)	2	(8)	(60)	(88)	(13)	(10)
Tax benefit of Tax Cuts and Jobs Act													(1,220)
Global Cellulose Fibers
Business Acquisition [Line Items]
Goodwill, Impairment Loss	52								52	[2]
North American Consumer Packaging [Member]
Business Acquisition [Line Items]
North American Consumer Packaging transaction costs							2	23
Non-operating pension expense (income)							28	(516)
Pre-tax charges (gains)							30	(493)
Riegelwood mill conversion costs
Business Acquisition [Line Items]
Restructuring and other charges, net													(14)
EMEA packaging restructuring
Business Acquisition [Line Items]
Restructuring and other charges, net	17				(1)		$ 26	$ 22	15	[3]	47	[4]
Riverdale mill conversion
Business Acquisition [Line Items]
Restructuring and other charges, net	2	1	1	$ 1	4	5					3
Early debt extinguishment costs (see Note 13)
Business Acquisition [Line Items]
Restructuring and other charges, net	21				10				21		10		83
Gain on sale of investment in Liaison Technologies Inc.
Business Acquisition [Line Items]
Restructuring and other charges, net					$ (31)						$ (31)
Overhead cost reduction initiative
Business Acquisition [Line Items]
Restructuring and other charges, net		21							21	[5]
Tax Cuts and Jobs Act [Member]
Business Acquisition [Line Items]
Tax benefit of Tax Cuts and Jobs Act						$ (36)							$ (1,454)
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | APPM [Member]
Business Acquisition [Line Items]
Gain (loss) on sale of assets and impairment charge allocated to minority interest		(2)	(7)						(9)
Divestiture costs	3
Brazil Packaging impairment	$ (1)	$ 8	$ 152						$ 159

[1] Includes sales of $15 million, operating profits (losses) of $0 million and corporate special items expense of $9 million in 2017 from previously divested businesses.

[2] Reflects the impairment of the Global Cellulose Fibers reporting unit.

[3] 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 will be paid in 2020.

[4] 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 the year.

[5] 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 will be paid in 2020.