MERGER WITH PLUM CREEK Recognized Identified Assets Acquired and Liabilities Assumed (Details) - Plum Creek $ in Billions	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Total assets acquired	$ 10.0
Total liabilities assumed	$ 3.6

Amount of liabilities assumed at the acquisition date.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84161108&loc=d3e4845-128472

Name:	us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant