EQUITY METHOD INVESTMENTS Narrative (Details) $ in Millions	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2021 USD ($)	Sep. 30, 2020	Jun. 30, 2020 USD ($)	Mar. 31, 2020	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2018	Dec. 31, 2020 USD ($)
Schedule of Equity Method Investments [Line Items]
Equity earnings (loss), net of taxes	$ 104		$ 72		$ 153	$ 41
Equity method dividends received					149	151
Reportable Subsegments | Graphic Packaging LLC [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of equity interest							20.50%
Equity method investments, aggregate units exchanged		17,399,414		15,150,784			79,911,591
Equity earnings (loss), net of taxes	$ 3		11		4	18
Equity method dividends received					$ 5	10
Reportable Subsegments | Ilim Holding
Schedule of Equity Method Investments [Line Items]
Percentage of equity interest	50.00%				50.00%
Equity earnings (loss), net of taxes	$ 101		63		$ 150	28
Equity method dividends received					144	141
Foreign currency transaction gain (loss), net of tax			34			(17)
Equity method investments	425				425			$ 393
Equity method investment, difference between carrying amount and underlying equity	128				128			$ 127
Related party transaction, purchases from related party	$ 42		$ 39		$ 83	$ 90