CHARGES FOR INTEGRATION AND RESTRUCTURING, CLOSURES AND ASSET IMPAIRMENTS - Items Included in Our Integration and Restructuring, Closure and Asset Impairment Charges (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Charges related to integration and restructuring
Termination benefits	$ 45
Charges related to closures and other restructuring activities	7	$ 1
Impairments of long-lived assets	0	13
Total charges for integration and restructuring, closures and impairments	117	14
Plum Creek [Member]
Charges related to integration and restructuring
Termination benefits	45	0
Acceleration of share-based compensation related to qualifying terminations	19	0
Acceleration of pension benefits related to qualifying terminations	5	0
Professional services	39	0
Other integration and restructuring costs	2	0
Total integration and restructuring charges related to our merger with Plum Creek	$ 110	$ 0	$ 14