BUSINESS SEGMENTS - Total Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 16,311	$ 16,406
Operating segments | Timberlands and Real Estate & ENR
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	12,874	13,130
Operating segments | Wood Products
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	2,619	2,452
Unallocated Items
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 818	$ 824