Goodwill And Other Intangibles (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2020
Goodwill [Line Items]
Intangibles subject to amortization, estimated amortization expense, next 12 months			$ 51
Intangibles subject to amortization, estimated amortization expense, year 2			46
Intangibles subject to amortization, estimated amortization expense, year 3			41
Intangibles subject to amortization, estimated amortization expense, year 4			41
Intangibles subject to amortization, estimated amortization expense, year 5			36
Intangibles subject to amortization, estimated amortization expense cumulatively thereafter			$ 96
Global Cellulose Fibers
Goodwill [Line Items]
Goodwill, Impairment Loss	$ (52)	$ (52)