(Information By Industry Segment, Capital Spending) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Capital Spending	$ 751	$ 1,276	$ 1,572
Subtotal
Segment Reporting Information [Line Items]
Capital Spending	738	1,256	1,547
Subtotal | Industrial Packaging
Segment Reporting Information [Line Items]
Capital Spending	525	922	1,061
Subtotal | Global Cellulose Fibers
Segment Reporting Information [Line Items]
Capital Spending	97	162	183
Subtotal | Printing Papers
Segment Reporting Information [Line Items]
Capital Spending	116	172	303
Corporate and other
Segment Reporting Information [Line Items]
Capital Spending	$ 13	$ 20	$ 25