Face (par) amount of debt instrument at time of issuance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 55

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

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

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(2))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum Debt Amount Guaranteed By Subsidiaries

+ References

No definition available.

+ Details

Name:	wlk_MinimumDebtAmountGuaranteedBySubsidiaries
Namespace Prefix:	wlk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage of the principal required in the event bonds are redeemed

+ References

No definition available.

+ Details

Name:	wlk_PercentageOfPrincipalRequiredIfCalled
Namespace Prefix:	wlk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DebtInstrumentAxis=wlk_GulfOpportunityZoneActOfTwoThousandFiveMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=wlk_DebtInstrumentRedemptionPeriodEightMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=wlk_DebtInstrumentRedemptionPeriodSevenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=wlk_GoZoneSixAndThreeQuartersPercentSeniorNotesDueTwentyThirtyTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Long-Term Debt (GO Zone Act Senior Notes Due 2032) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended	1 Months Ended
	Dec. 31, 2014	Jul. 31, 2010	Dec. 31, 2007	Dec. 31, 2013	Jul. 02, 2010	Dec. 13, 2007
Debt Instrument [Line Items]
Stated interest rate	6.50%
Minimum debt amount guaranteed by subsidiaries	5,000
GO Zone 6 3/4% Senior Notes Due 2032 [Member]
Debt Instrument [Line Items]
Stated interest rate	6.75%			6.75%
Redeemed Prior To November 1, 2017 [Member] \| GO Zone 6 3/4% Senior Notes Due 2032 [Member]
Debt Instrument [Line Items]
Percentage of principal required if called	100.00%
Redeemed On Or After November 1, 2017 [Member] \| GO Zone 6 3/4% Senior Notes Due 2032 [Member]
Debt Instrument [Line Items]
Percentage of principal required if called	100.00%
Gulf Opportunity Zone Act Of 2005 [Member]
Debt Instrument [Line Items]
Senior notes, principal amount issued					100,000
Maturity date		Aug. 01, 2029
Gulf Opportunity Zone Act Of 2005 [Member] \| GO Zone 6 3/4% Senior Notes Due 2032 [Member]
Debt Instrument [Line Items]
Senior notes, principal amount issued						$ 250,000
Stated interest rate						6.75%
Maturity date			Nov. 01, 2032