LEGAL PROCEEDINGS, COMMITMENTS AND CONTINGENCIES - Changes in the Reserve for Asset Retirement Obligations (Details) $ in Millions	12 Months Ended
Dec. 31, 2017 USD ($)
Loss Contingencies [Line Items]
Reserve balance as of December 31, 2016(1)	$ 29
Reserve charges and adjustments, net	12
Payments	(11)
Other adjustments(2)	2
Reserve balance as of December 31, 2017	$ 32

The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

+ Details

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

- Definition

Amount of cash paid during the period to settle an asset retirement obligation. Amounts paid to settle an asset retirement obligation are generally included in the operating section of the Statement of Cash Flows.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 17
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3367-108585

+ Details

Name:	us-gaap_AssetRetirementObligationCashPaidToSettle
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of asset retirement obligations incurred during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

+ Details

Name:	us-gaap_AssetRetirementObligationLiabilitiesIncurred
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_LossContingenciesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the Increase or Decrease in the amount of asset retirement obligations for the period associated with other adjustments.

+ References

No definition available.

+ Details

Name:	wy_AssetRetirementObligationOtherAdjustments
Namespace Prefix:	wy_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration