(Information By Industry Segment, Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Assets	$ 31,718	$ 33,471
Operating Segments [Member] | Industrial Packaging
Segment Reporting Information [Line Items]
Assets	15,976	16,338
Operating Segments [Member] | Global Cellulose Fibers
Segment Reporting Information [Line Items]
Assets	3,507	3,733
Operating Segments [Member] | Printing Papers
Segment Reporting Information [Line Items]
Assets	2,855	3,476
Corporate and other | Corporate and Other
Segment Reporting Information [Line Items]
Assets	$ 9,380	$ 9,924