Westlake (WLK) 10-Q3 Nov 212021 Q3 Quarterly reportFinancial data

Company Profile

Cover Page

Cover Page - shares	9 Months Ended
Cover Page - shares	Sep. 30, 2021	Oct. 27, 2021
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-32260
Entity Registrant Name	Westlake Chemical Corporation
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	76-0346924
Entity Address, Address Line One	2801 Post Oak Boulevard
Entity Address, Address Line Two	Suite 600
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77056
City Area Code	713
Local Phone Number	960-9111
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		127,821,964
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001262823
Current Fiscal Year End Date	--12-31
Common Stock
Document Information [Line Items]
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	WLK
Security Exchange Name	NYSE
1.625% Senior Notes Due 2029
Document Information [Line Items]
Title of 12(b) Security	1.625% Senior Notes due 2029
Trading Symbol	WLK29
Security Exchange Name	NYSE

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 3,571	$ 1,313
Accounts receivable, net	1,642	1,214
Inventories	1,124	918
Prepaid expenses and other current assets	98	32
Total current assets	6,435	3,477
Property, plant and equipment, net	6,992	6,920
Operating lease right-of-use assets	479	461
Goodwill	1,253	1,083
Customer relationships, net	470	444
Other intangible assets, net	198	168
Equity method investments	1,010	1,059
Other assets, net	271	223
Total assets	17,108	13,835
Current liabilities
Accounts payable	718	536
Accrued and other liabilities	912	821
Current portion of long-term debt, net	268	0
Total current liabilities	1,898	1,357
Long-term debt, net	4,929	3,566
Deferred income taxes	1,445	1,368
Pension and other post-retirement benefits	362	391
Operating lease liabilities	392	376
Other liabilities	213	199
Total liabilities	9,239	7,257
Commitments and contingencies (Note 14)
Stockholders' equity
Preferred stock, $0.01 par value, 50,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $0.01 par value, 300,000,000 shares authorized; 134,651,380 and 134,651,380 shares issued at September 30, 2021 and December 31, 2020, respectively	1	1
Common stock, held in treasury, at cost; 6,830,317 and 6,821,174 shares at September 30, 2021 and December 31, 2020, respectively	(406)	(401)
Additional paid-in capital	576	569
Retained earnings	7,202	5,938
Accumulated other comprehensive loss	(75)	(64)
Total Westlake Chemical Corporation stockholders' equity	7,298	6,043
Noncontrolling interests	571	535
Total equity	7,869	6,578
Total liabilities and equity	$ 17,108	$ 13,835

Consolidated Balance Sheets (_2

Consolidated Balance Sheets (Unaudited) (Parentheticals) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Preferred stock, par value, in dollars per share	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value, in dollars per share	$ 0.01	$ 0.01
Common stock, shares authorized	300,000,000	300,000,000
Common Stock
Common Stock, Shares, Issued	134,651,380	134,651,380
Common Stock, Held in Treasury
Treasury Stock, Shares	6,830,317	6,821,174

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Net sales	$ 3,055	$ 1,898	$ 8,271	$ 5,539
Cost of sales	2,037	1,650	5,872	4,839
Gross profit	1,018	248	2,399	700
Selling, general and administrative expenses	122	108	383	332
Amortization of intangibles	29	27	83	81
Restructuring, transaction and integration-related costs	6	34	6	36
Income from operations	861	79	1,927	251
Other income (expense)
Interest expense	(61)	(37)	(130)	(108)
Other income, net	13	12	35	32
Income before income taxes	813	54	1,832	175
Provision for (benefit from) income taxes	193	(15)	423	(75)
Net income	620	69	1,409	250
Net income attributable to noncontrolling interests	13	12	38	33
Net income attributable to Westlake Chemical Corporation	$ 607	$ 57	$ 1,371	$ 217
Earnings per common share attributable to Westlake Chemical Corporation:
Basic (in dollars per share)	$ 4.71	$ 0.45	$ 10.65	$ 1.69
Diluted (in dollars per share)	$ 4.69	$ 0.45	$ 10.60	$ 1.69
Weighted average common shares outstanding:
Basic (in shares)	128,060,193	127,701,340	128,053,337	127,872,434
Diluted (in shares)	128,765,814	127,953,907	128,710,097	128,073,066

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 620	$ 69	$ 1,409	$ 250
Pension and other post-retirement benefits liability
Pension and other post-retirement benefits reserves adjustment	1	0	1	0
Income tax provision on pension and other post-retirement benefits liability	(1)	0	(1)	0
Foreign currency translation adjustments
Foreign currency translation	(13)	10	2	0
Income tax benefit (provision) on foreign currency translation	(6)	9	(13)	7
Other comprehensive income (loss), net of income taxes	(19)	19	(11)	7
Comprehensive income	601	88	1,398	257
Comprehensive income attributable to noncontrolling interests, net of tax of $1 and $0 for the three months ended September 30, 2021 and 2020; and net of tax of $2 and $1 for the nine months ended September 30, 2021 and 2020, respectively	13	13	38	35
Comprehensive income attributable to Westlake Chemical Corporation	$ 588	$ 75	$ 1,360	$ 222

Consolidated Statements Of Chan

Consolidated Statements Of Changes In Stockholders' Equity Statement - USD ($) $ in Millions	Total	Common Stock	Common Stock, Held in Treasury	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]
Beginning balances at Dec. 31, 2019	$ 6,403	$ 1	$ (377)	$ 553	$ 5,757	$ (74)	$ 543
Beginning balance, shares issued at Dec. 31, 2019		134,651,380
Beginning balance, Treasury shares at Dec. 31, 2019			6,266,609
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to Westlake Chemical Corporation					145
Net income attributable to noncontrolling interests							12
Net income	157
Other comprehensive income	(32)					(32)	0
Common stock repurchased, shares			995,529
Common stock repurchased	(54)		$ (54)
Shares issued—stock- based compensation (in shares)			(282,476)
Shares issued—stock-based compensation	2		$ 18	(8)	(8)
Stock-based compensation	6			6
Dividends declared	(34)				(34)
Distributions to noncontrolling interests	(10)						(10)
Ending balances at Mar. 31, 2020	6,438	$ 1	$ (413)	551	5,860	(106)	545
Ending balance, shares issued at Mar. 31, 2020		134,651,380
Ending balance, Treasury shares at Mar. 31, 2020			6,979,662
Beginning balances at Dec. 31, 2019	6,403	$ 1	$ (377)	553	5,757	(74)	543
Beginning balance, shares issued at Dec. 31, 2019		134,651,380
Beginning balance, Treasury shares at Dec. 31, 2019			6,266,609
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to Westlake Chemical Corporation	217
Net income attributable to noncontrolling interests	33
Net income	250
Other comprehensive income	7
Ending balances at Sep. 30, 2020	6,488	$ 1	$ (409)	563	5,863	(69)	539
Ending balance, shares issued at Sep. 30, 2020		134,651,380
Ending balance, Treasury shares at Sep. 30, 2020			6,930,624
Beginning balances at Mar. 31, 2020	6,438	$ 1	$ (413)	551	5,860	(106)	545
Beginning balance, shares issued at Mar. 31, 2020		134,651,380
Beginning balance, Treasury shares at Mar. 31, 2020			6,979,662
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to Westlake Chemical Corporation					15
Net income attributable to noncontrolling interests							9
Net income	24
Other comprehensive income	20					19	1
Shares issued—stock- based compensation (in shares)			(16,331)
Shares issued—stock-based compensation	0		$ 2	(1)	(1)
Stock-based compensation	8			8
Dividends declared	(34)				(34)
Distributions to noncontrolling interests	(19)						(19)
Ending balances at Jun. 30, 2020	6,437	$ 1	$ (411)	558	5,840	(87)	536
Ending balance, shares issued at Jun. 30, 2020		134,651,380
Ending balance, Treasury shares at Jun. 30, 2020			6,963,331
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to Westlake Chemical Corporation	57				57
Net income attributable to noncontrolling interests	12						12
Net income	69
Other comprehensive income	19					18	1
Shares issued—stock- based compensation (in shares)			(32,707)
Shares issued—stock-based compensation	0		$ 2	(2)	0
Stock-based compensation	7			7
Dividends declared	(34)				(34)
Distributions to noncontrolling interests	(10)						(10)
Ending balances at Sep. 30, 2020	6,488	$ 1	$ (409)	563	5,863	(69)	539
Ending balance, shares issued at Sep. 30, 2020		134,651,380
Ending balance, Treasury shares at Sep. 30, 2020			6,930,624
Beginning balances at Dec. 31, 2020	6,578	$ 1	$ (401)	569	5,938	(64)	535
Beginning balance, shares issued at Dec. 31, 2020		134,651,380
Beginning balance, Treasury shares at Dec. 31, 2020			6,821,174
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to Westlake Chemical Corporation					242
Net income attributable to noncontrolling interests							11
Net income	253
Other comprehensive income	(7)					(6)	(1)
Shares issued—stock- based compensation (in shares)			(301,112)
Shares issued—stock-based compensation	9		$ 22	(13)
Stock-based compensation	8			8
Dividends declared	(35)				(35)
Distributions to noncontrolling interests	(11)						(11)
Noncontrolling Interest, Increase from Consolidating Previously Unconsolidated Subsidiary	30						30
Ending balances at Mar. 31, 2021	6,825	$ 1	$ (379)	564	6,145	(70)	564
Ending balance, shares issued at Mar. 31, 2021		134,651,380
Ending balance, Treasury shares at Mar. 31, 2021			6,520,062
Beginning balances at Dec. 31, 2020	6,578	$ 1	$ (401)	569	5,938	(64)	535
Beginning balance, shares issued at Dec. 31, 2020		134,651,380
Beginning balance, Treasury shares at Dec. 31, 2020			6,821,174
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to Westlake Chemical Corporation	1,371
Net income attributable to noncontrolling interests	38
Net income	1,409
Other comprehensive income	(11)
Ending balances at Sep. 30, 2021	7,869	$ 1	$ (406)	576	7,202	(75)	571
Ending balance, shares issued at Sep. 30, 2021		134,651,380
Ending balance, Treasury shares at Sep. 30, 2021			6,830,317
Beginning balances at Mar. 31, 2021	6,825	$ 1	$ (379)	564	6,145	(70)	564
Beginning balance, shares issued at Mar. 31, 2021		134,651,380
Beginning balance, Treasury shares at Mar. 31, 2021			6,520,062
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to Westlake Chemical Corporation					522
Net income attributable to noncontrolling interests							14
Net income	536
Other comprehensive income	15					14	1
Shares issued—stock- based compensation (in shares)			(18,397)
Shares issued—stock-based compensation	1		$ 1	0	0
Stock-based compensation	7			7
Dividends declared	(34)				(34)
Distributions to noncontrolling interests	(11)						(11)
Ending balances at Jun. 30, 2021	7,339		$ (378)	571	6,633	(56)	568
Ending balance, Treasury shares at Jun. 30, 2021			6,501,665
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to Westlake Chemical Corporation	607				607
Net income attributable to noncontrolling interests	13						13
Net income	620
Other comprehensive income	(19)					(19)	0
Common stock repurchased, shares			355,800
Common stock repurchased	(30)		$ (30)
Shares issued—stock- based compensation (in shares)			(27,148)
Shares issued—stock-based compensation	0		$ 2	(2)	0
Stock-based compensation	7			7
Dividends declared	(38)				(38)
Distributions to noncontrolling interests	(10)						(10)
Ending balances at Sep. 30, 2021	$ 7,869	$ 1	$ (406)	$ 576	$ 7,202	$ (75)	$ 571
Ending balance, shares issued at Sep. 30, 2021		134,651,380
Ending balance, Treasury shares at Sep. 30, 2021			6,830,317

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities
Net income	$ 1,409	$ 250
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	600	577
Stock-based compensation expense	23	21
Loss from disposition and write-off of property, plant and equipment	14	26
Deferred income taxes	50	154
Other losses, net	21	23
Changes in operating assets and liabilities, net of effect of business acquisitions
Accounts receivable	(414)	(251)
Inventories	(180)	108
Prepaid expenses and other current assets	(49)	(8)
Accounts payable	184	17
Accrued and other liabilities	78	14
Other, net	(99)	(65)
Net cash provided by operating activities	1,637	866
Cash flows from investing activities
Acquisition of businesses, net of cash acquired	(428)	0
Additions to property, plant and equipment	(414)	(403)
Return of (additions to) investment from unconsolidated subsidiaries	(19)	44
Other, net	19	(7)
Net cash used for investing activities	(842)	(366)
Cash flows from financing activities
Debt issuance costs	(18)	(3)
Distributions to noncontrolling interests	(32)	(39)
Dividends paid	(107)	(102)
Proceeds from debt issuance and drawdown of revolver, net	1,668	1,299
Proceeds from (repayment of) short-term notes payable, net	5	(17)
Repayment of revolver and senior notes	0	(1,100)
Repurchase of common stock for treasury	(30)	(54)
Other, net	1	2
Net cash provided by (used for) financing activities	1,487	(14)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(9)	4
Net increase in cash, cash equivalents and restricted cash	2,273	490
Cash, cash equivalents and restricted cash at beginning of period	1,337	750
Cash, cash equivalents and restricted cash at end of period	$ 3,610	$ 1,240

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Unaudited) Parenthetical - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Other Comprehensive Income (Loss), Tax, Portion Attributable to Noncontrolling Interest	$ 1	$ 0	$ 2	$ 1

Basis of Financial Statements (

Basis of Financial Statements (Notes)	9 Months Ended
Basis of Financial Statements (Notes)	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Financial Statements	Basis of Financial Statements The accompanying unaudited consolidated interim financial statements were prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the "SEC") for interim periods. Accordingly, certain information and footnotes required for complete financial statements under generally accepted accounting principles in the United States ("U.S. GAAP") have not been included. These interim consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto of Westlake Chemical Corporation (the "Company") included in the annual report on Form 10-K for the fiscal year ended December 31, 2020 (the "2020 Form 10-K"), filed with the SEC on February 24, 2021. These consolidated financial statements have been prepared in conformity with the accounting principles and practices as disclosed in the notes to the consolidated financial statements of the Company for the fiscal year ended December 31, 2020. In the opinion of the Company's management, the accompanying unaudited consolidated interim financial statements reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for a fair statement of the Company's financial position as of September 30, 2021, its results of operations for the three and nine months ended September 30, 2021 and 2020, and the changes in its cash position for the nine months ended September 30, 2021 and 2020. Results of operations and changes in cash position for the interim periods presented are not necessarily indicative of the results that will be realized for the fiscal year ending December 31, 2021 or any other interim period. The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities. Actual results could differ from those estimates. The coronavirus ("COVID-19") pandemic resulted in widespread adverse impacts on the global economy in 2020. As the COVID-19 pandemic and its impacts on the global economy continue, the Company may experience impacts on its business operations. However, the impact that COVID-19 will have on the financial condition, results of operations and cash flows of the Company cannot be estimated with certainty at this time as it will depend on future developments, including, among others, the timing and logistics with respect to the distribution of vaccines globally and the efficacy of the available vaccines (including with respect to the more recent variants of COVID-19) and other treatments, the ultimate duration of the pandemic, geographic spread and severity of the virus, the consequences of governmental and other measures designed to prevent the spread of the virus, actions taken by customers, suppliers and other third parties, workforce availability, and the timing and extent to which normal economic and operating conditions resume. The Company holds a 50% interest in RS Cogen, LLC ("RS Cogen") with Entergy Power RS, LLC ("Entergy") holding the remaining interest. Effective January 2021, the Company consolidated RS Cogen into its consolidated financial statements and classified Entergy's 50% interest in RS Cogen as a component of noncontrolling interest on the consolidated balance sheet. Recent Accounting Pronouncements Reference Rate Reform (ASU No. 2020-04) In March 2020, the Financial Accounting Standards Board ("FASB") issued an accounting standards update to provide optional expedients and exceptions for applying generally accepted accounting principles to contracts, hedging relationships and other transactions affected by reference rate reform, if certain criteria are met. The amendments in this update are effective for all entities from March 12, 2020 through December 31, 2022, and the adoption is not expected to have a material impact on our consolidated financial statements. Certain exceptions provided under this guidance may be applicable to future reference rate reform related transitions. Recently Adopted Accounting Standards Income Taxes (ASU No. 2019-12) In December 2019, the FASB issued an accounting standards update removing certain exceptions for investments, intraperiod allocations and interim calculations and adding guidance to reduce complexity in accounting for income taxes. The accounting standard became effective for reporting periods beginning after December 15, 2020. The Company adopted this accounting standard effective January 1, 2021, and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows.

Acquisitions

Acquisitions	9 Months Ended
Acquisitions	Sep. 30, 2021
Business Combination and Asset Acquisition [Abstract]
Acquisitions	Acquisitions Boral Target Companies in North America. On June 20, 2021, Royal Building Products (USA) Inc. ("RBP"), a wholly-owned subsidiary of Westlake, entered into an Equity Purchase Agreement (the "Boral Purchase Agreement") by and among Boral Building Products Inc., a Michigan corporation, Boral Stone Products LLC, a Delaware limited liability company, Boral Lifetile Inc., a California corporation, Boral Windows LLC, a Utah limited liability company, Boral Industries Inc., a California corporation ("Boral Industries"), RBP and, solely for the limited purposes set forth therein, Westlake and Boral Limited, an Australian corporation ("Boral"). Pursuant to the terms of the Boral Purchase Agreement, RBP agreed to acquire from Boral Industries all of the issued and outstanding equity interests of certain subsidiaries of Boral Industries engaged in Boral's North American building products businesses in roofing, siding, trim and shutters, decorative stone and windows (the "Boral Target Companies") for a purchase price of $2,150 in cash, subject to working capital post-closing adjustments. The Boral Purchase Agreement also includes a potential earn-out payment from RBP to Boral Industries of up to $65 if Boral's windows business generates EBITDA in excess of a specified target in its fiscal year ending June 30, 2024. The acquisition will be accounted for under the acquisition method of accounting. The fair value of the estimated earn-out will be recognized as contingent consideration liability as part of the Company's purchase accounting. On October 1, 2021, the Company completed the acquisition of, and acquired all of the equity interests in, the Boral Target Companies. Due to the recent closing of this acquisition, certain financial information related to this acquisition, including the fair value of total consideration transferred or estimated to be transferred, is not yet finalized. LASCO Fittings, Inc . On July 4, 2021, North American Pipe Corporation ("NAPCO"), a wholly-owned subsidiary of Westlake, entered into an Equity Purchase Agreement with Aalberts U.S. Holding Corp., a Delaware corporation ("Aalberts") and wholly-owned subsidiary of Aalberts N.V., pursuant to which NAPCO agreed to acquire LASCO Fittings, Inc., a Delaware corporation ("LASCO"), from Aalberts. LASCO is a manufacturer of injected-molded PVC fittings that serve the plumbing, pool and spa, industrial, irrigation and retail markets in the United States. On August 19, 2021, the Company completed its acquisition of, and acquired all of the equity interests in, LASCO. The total closing purchase consideration was $277. The acquisition is being accounted for under the acquisition method of accounting. The assets acquired and liabilities assumed and the results of operations of LASCO are included in the Vinyls segment. LASCO net sales and net income since the acquisition date and the acquisition-related costs recognized in the consolidated statement of operations for the three and nine months ended September 30, 2021 were not material to the Company's consolidated statement of operations. The pro forma impact of this acquisition has not been presented as it is not material to the Company's consolidated statements of operations for the nine months ended September 30, 2021 and 2020. The Company recognized intangible assets of $77, of which $50 is included in customer relationships, net on the Company's consolidated balance sheets as of September 30, 2021, and goodwill of $106 with the remainder of the purchase consideration primarily allocated to property, plant, and equipment, net and working capital balances. The goodwill is expected to be deductible for income tax purposes. The goodwill recognized is primarily attributable to the expected value to be achieved from the acquisition. The intangible assets that have been acquired are being amortized over a period of 17 to 18 years. Dimex LLC . On August 2, 2021, Rome Delaware Corp. ("Rome"), a wholly-owned subsidiary of Westlake, entered into a Stock Purchase Agreement with DX Acquisition Corp., a Delaware corporation ("Dimex"), each of Dimex's stockholders, and for limited purposes, Westlake and Grey Mountain Partners Fund III Holdings, L.P., pursuant to which Rome agreed to acquire Dimex. Dimex is a producer of various consumer products made from post-industrial-recycled polyvinyl chloride, polyethylene and thermoplastic elastomer materials, including landscape edging; industrial, home and office matting; marine dock edging; and masonry joint controls. On September 10, 2021, the Company completed its acquisition of, and acquired all of the equity interests in, Dimex. The total closing purchase consideration was $172, subject to working capital post-closing adjustments. The acquisition is being accounted for under the acquisition method of accounting. The assets acquired and liabilities assumed and the results of operations of Dimex are included in the Vinyls segment. Dimex net sales and net income since the acquisition date and the acquisition-related costs recognized in the consolidated statement of operations for the three and nine months ended September 30, 2021 were not material to the Company's consolidated statement of operations. The pro forma impact of this acquisition has not been presented as it is not material to the Company's consolidated statements of operations for the nine months ended September 30, 2021 and 2020. The Company recognized intangible assets of $69, of which $45 is included in customer relationships, net on the Company's consolidated balance sheets as of September 30, 2021, and goodwill of $66 with the remainder of the purchase consideration primarily allocated to property, plant, and equipment, net and working capital balances. The goodwill is not expected to be deductible for income tax purposes and is primarily attributable to the expected value to be achieved from the acquisition. The intangible assets that have been acquired are being amortized over a period of 17 to 19 years.

Financial Instruments (Notes)

Financial Instruments (Notes)	9 Months Ended
Financial Instruments (Notes)	Sep. 30, 2021
Investments, Debt and Equity Securities [Abstract]
Financial Instruments	Financial Instruments Restricted Cash and Cash Equivalents The Company had restricted cash and cash equivalents of $39 and $24 at September 30, 2021 and December 31, 2020, respectively. The Company's restricted cash and cash equivalents are primarily related to balances that are restricted for payment of distributions to certain of the Company's current and former employees. In addition, the Company's restricted cash and cash equivalents include RS Cogen's cash that is restricted under its senior credit facility. Restricted cash and cash equivalents are reflected primarily in other assets, net in the consolidated balance sheets.

Accounts Receivable (Notes)

Accounts Receivable (Notes)	9 Months Ended
Accounts Receivable (Notes)	Sep. 30, 2021
Accounts Receivable, after Allowance for Credit Loss [Abstract]
Accounts Receivable	Accounts Receivable Accounts receivable consist of the following: September 30, December 31, Trade customers $ 1,553 $ 1,086 Related parties 2 9 Allowance for credit losses (23) (17) 1,532 1,078 Federal and state taxes 49 92 Other 61 44 Accounts receivable, net $ 1,642 $ 1,214

Inventories (Notes)

Inventories (Notes)	9 Months Ended
Inventories (Notes)	Sep. 30, 2021
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consist of the following: September 30, December 31, Finished products $ 639 $ 524 Feedstock, additives, chemicals and other raw materials 316 227 Materials and supplies 169 167 Inventories $ 1,124 $ 918

Goodwill (Notes)

Goodwill (Notes)	9 Months Ended
Goodwill (Notes)	Sep. 30, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill The gross carrying amounts and changes in the carrying amount of goodwill for the nine months ended September 30, 2021 were as follows: Vinyls Segment Olefins Segment Total Balances at December 31, 2020 $ 1,053 $ 30 $ 1,083 Goodwill acquired during the period 172 — 172 Effects of changes in foreign exchange rates (2) — (2) Balances at September 30, 2021 $ 1,223 $ 30 $ 1,253 The Company performed its annual impairment analysis for the Vinyls reporting units during the second quarter of 2021 and determined that it is more likely than not that the fair value of each of the Vinyls reporting units exceeds its carrying value. Factors considered in the qualitative assessment included macroeconomic conditions, industry and market considerations, cost factors, current and projected financial performance, changes in management or strategy and market capitalization.

Accounts Payable (Notes)

Accounts Payable (Notes)	9 Months Ended
Accounts Payable (Notes)	Sep. 30, 2021
Accounts Payable [Abstract]
Accounts and Notes Payable	Accounts Payable Accounts payable consist of the following: September 30, December 31, Accounts payable—third parties $ 687 $ 529 Accounts payable to related parties 17 — Notes payable 14 7 Accounts payable $ 718 $ 536

Long-Term Debt (Notes)

Long-Term Debt (Notes)	9 Months Ended
Long-Term Debt (Notes)	Sep. 30, 2021
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt Long-term debt consists of the following: September 30, 2021 December 31, 2020 Principal Unamortized Net Principal Unamortized Net 3.60% senior notes due 2022 (the "3.60% 2022 Senior Notes") $ 250 $ — $ 250 $ 250 $ (1) $ 249 0.875% senior notes due 2024 (the "0.875% 2024 Senior Notes") 300 (2) 298 — — — 3.60% senior notes due 2026 (the "3.60% 2026 Senior Notes") 750 (6) 744 750 (6) 744 Loan related to tax-exempt waste disposal revenue bonds due 2027 11 11 11 — 11 1.625% senior notes due 2029 (the "1.625% 2029 Senior Notes") 811 (9) 802 859 (10) 849 3.375% senior notes due 2030 (the "3.375% 2030 Senior Notes") 300 (4) 296 300 (4) 296 3.50% senior notes due 2032 (the "3.50% 2032 GO Zone Refunding Senior Notes") 250 (1) 249 250 (1) 249 2.875% senior notes due 2041 (the "2.875% 2041 Senior Notes") 350 (11) 339 — — — 5.0% senior notes due 2046 (the "5.0% 2046 Senior Notes") 700 (22) 678 700 (23) 677 4.375% senior notes due 2047 (the "4.375% 2047 Senior Notes") 500 (8) 492 500 (9) 491 3.125% senior notes due 2051 (the "3.125% 2051 Senior Notes") 600 (23) 577 — — — 3.375% senior notes due 2061 (the "3.375% 2061 Senior Notes") 450 (19) 431 — — — 8.73% RS Cogen debt due 2022 (the "8.73% 2022 RS Cogen Debt") 24 24 — — — Term loans due 2026 (the "2026 Term Loans") 6 — 6 — — — Total long-term debt 5,302 (105) 5,197 3,620 (54) 3,566 Less current portion: 3.60% 2022 Senior Notes (250) — (250) — — — 8.73% 2022 RS Cogen Debt (18) — (18) — — — Long-term debt, net of current portion $ 5,034 $ (105) $ 4,929 $ 3,620 $ (54) $ 3,566 Unamortized debt issuance costs on long-term debt were $43 and $28 at September 30, 2021 and December 31, 2020, respectively. As of September 30, 2021, the Company was in compliance with all of its long-term debt covenants. Credit Agreement The Company has a $1,000 revolving credit facility that is scheduled to mature on July 24, 2023 (the "Credit Agreement"). The Credit Agreement bears interest at either (a) LIBOR plus a spread ranging from 1.00% to 1.75% or (b) Alternate Base Rate plus a spread ranging from 0.00% to 0.75% in each case depending on the credit rating of the Company. At September 30, 2021, the Company had no borrowings outstanding under the Credit Agreement. As of September 30, 2021, the Company had no outstanding letters of credit and had $1,000 of borrowing availability under the Credit Agreement. The Credit Agreement contains certain affirmative and negative covenants, including a quarterly total leverage ratio financial maintenance covenant. As of September 30, 2021, the Company was in compliance with the total leverage ratio financial maintenance covenant. The Credit Agreement also contains certain events of default and if and for so long as certain events of default have occurred and are continuing, any overdue amounts outstanding under the Credit Agreement will accrue interest at an increased rate, the lenders can terminate their commitments thereunder and payments of any outstanding amounts could be accelerated by the lenders. The Credit Agreement includes a $150 sub-limit for letters of credit, and any outstanding letters of credit will be deducted from availability under the facility. The Credit Agreement also provides for a discretionary $50 commitment for swingline loans to be provided on a same-day basis. The Company may also increase the size of the facility, in increments of at least $25, up to a maximum of $500, subject to certain conditions and if certain lenders agree to commit to such an increase . Senior Notes Offering On August 19, 2021, the Company completed the registered public offering of $300 aggregate principal amount of 0.875% senior notes due 2024 (the “0.875% 2024 Senior Notes”), $350 aggregate principal amount of 2.875% senior notes due 2041 (the “2.875% 2041 Senior Notes”), $600 aggregate principal amount of 3.125% senior notes due 2051 (the “3.125% 2051 Senior Notes”) and $450 aggregate principal amount of 3.375% senior notes due 2061 (the “3.375% 2061 Senior Notes” and, together with the 0.875% 2024 Senior Notes, the 2.875% 2041 Senior Notes and the 3.125% 2051 Senior Notes, the “Notes”). There is no sinking fund and no scheduled amortization of each series of Notes prior to maturity of such respective series. The 0.875% 2024 Senior Notes will accrue interest at a rate of 0.875% per annum, the 2.875% 2041 Senior Notes will accrue interest at a rate of 2.875% per annum, the 3.125% 2051 Senior Notes will accrue interest at a rate of 3.125% per annum and the 3.375% 2061 Senior Notes will accrue interest at a rate of 3.375% per annum. Interest on each series of Notes will accrue from August 19, 2021 and will be payable semi-annually in arrears on February 15 and August 15 of each year, beginning February 15, 2022. The indenture and supplemental indenture governing the Notes contain customary events of default and covenants that restrict the Company and certain of its subsidiaries’ ability to (1) incur certain secured indebtedness, (2) engage in certain sale-leaseback transactions and (3) consolidate, merge or transfer all or substantially all of its assets. The Company may optionally redeem each series of Notes in accordance with the terms of such series of Notes. The Notes are unsecured and none of the Company's subsidiaries have guaranteed any series of the Notes. 8.73% 2022 RS Cogen Debt In July 2000, RS Cogen, our 50%-owned joint venture, entered into a $75 aggregate principal amount senior credit facility institutional loan at an interest rate of 8.73%. All of the assets of RS Cogen are pledged as collateral under its senior credit facility. Borrowings under this senior credit facility are repayable quarterly by September 2022. The Company does not guarantee RS Cogen's debt commitments and RS Cogen is not a guarantor for any of the Company's other long-term debt obligations. 2026 Term Loans In March 2021, Taiwan Chlorine Industries, Ltd., our 60%-owned joint venture, entered into five-year loan agreements for a maximum total limit of approximately $23. The interest rate on these loans at September 30, 2021 was 0.20%. The unsecured loans include a government rate subsidy and have a 5-year maturity.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss) (Notes)	9 Months Ended
Accumulated Other Comprehensive Income (Loss) (Notes)	Sep. 30, 2021
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Changes in accumulated other comprehensive income (loss) by component for the nine months ended September 30, 2021 and 2020 were as follows: Pension and Other Post-Retirement Benefits Cumulative Total Balances at December 31, 2020 $ (24) $ (40) $ (64) Other comprehensive loss attributable to Westlake Chemical Corporation — (11) (11) Balances at September 30, 2021 $ (24) $ (51) $ (75) Balances at December 31, 2019 $ 3 $ (77) $ (74) Other comprehensive income attributable to Westlake Chemical Corporation — 5 5 Balances at September 30, 2020 $ 3 $ (72) $ (69)

Fair Value Measurements (Notes)

Fair Value Measurements (Notes)	9 Months Ended
Fair Value Measurements (Notes)	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Company reports certain assets and liabilities at fair value, which is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). Under the accounting guidance for fair value measurements, inputs used to measure fair value are classified in one of three levels: Level 1: Quoted market prices in active markets for identical assets or liabilities. Level 2: Observable market-based inputs or unobservable inputs that are corroborated by market data. Level 3: Unobservable inputs that are not corroborated by market data. The Company has financial assets and liabilities subject to fair value measures. These financial assets and liabilities include cash and cash equivalents, accounts receivable, net, accounts payable and long-term debt, all of which are recorded at carrying value. The amounts reported in the consolidated balance sheets for cash and cash equivalents, accounts receivable, net and accounts payable approximate their fair value due to the short maturities of these instruments. The majority of the Company's long-term debt instruments are publicly-traded. A market approach, based upon quotes from financial reporting services, is used to measure the fair value of the Company's long-term debt. Because the Company's long-term debt instruments may not be actively traded, the inputs used to measure the fair value of the Company's long-term debt are classified as Level 2 inputs within the fair value hierarchy. The carrying and fair values of the Company's long-term debt are summarized in the table below. September 30, 2021 December 31, 2020 Carrying Fair Carrying Fair 3.60% 2022 Senior Notes $ 250 $ 254 $ 249 $ 259 0.875% 2024 Senior Notes 298 301 — — 3.60% 2026 Senior Notes 744 825 744 846 Loan related to tax-exempt waste disposal revenue bonds due 2027 11 11 11 11 1.625% 2029 Senior Notes 802 860 849 897 3.375% 2030 Senior Notes 296 325 296 332 3.50% 2032 GO Zone Refunding Senior Notes 249 276 249 276 2.875% 2041 Senior Notes 339 337 — — 5.0% 2046 Senior Notes 678 872 677 905 4.375% 2047 Senior Notes 492 577 491 597 3.125% 2051 Senior Notes 577 571 — — 3.375% 2061 Senior Notes 431 427 — — 8.73% 2022 RS Cogen Debt 24 24 — — 2026 Term Loans 6 6 — —

Income Taxes (Notes)

Income Taxes (Notes)	9 Months Ended
Income Taxes (Notes)	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The effective income tax rate was an expense of 23.7% for the three months ended September 30, 2021 as compared to a benefit of 27.8% for the three months ended September 30, 2020. The effective income tax rate for the three months ended September 30, 2021 was above the statutory rate of 21.0% primarily due to state and foreign taxes. The effective income tax rate for the three months ended September 30, 2020 was a benefit and below the statutory rate of 21.0% primarily due to the income tax rate benefit resulting from the carryback of additional federal net operating loss ("NOL") to taxable years that were taxed at the U.S. corporate tax rate of 35.0% as permitted under the Coronavirus Aid, Relief, and Economic Security Act (the "CARES Act"), partially offset by the reduction in the Internal Revenue Code Section 199 ("Section 199") domestic manufacturing deduction as a result of the NOL carryback. The effective income tax rate was an expense of 23.1% for the nine months ended September 30, 2021 as compared to a benefit of 42.9% for the nine months ended September 30, 2020. The effective income tax rate for the nine months ended September 30, 2021 was above the statutory rate of 21.0% primarily due to state and foreign taxes. The effective income tax rate for the nine months ended September 30, 2020 was a benefit and below the statutory rate of 21.0% primarily due to the income tax rate benefit resulting from the carryback of federal NOL to taxable years that were taxed at the U.S. corporate tax rate of 35.0% as permitted under the CARES Act, partially offset by the reduction in the Section 199 domestic manufacturing deduction as a result of the NOL carryback, the depletion deduction, the foreign earnings rate differential and the state income tax benefit.

Earnings and Dividends per Shar

Earnings and Dividends per Share (Notes)	9 Months Ended
Earnings and Dividends per Share (Notes)	Sep. 30, 2021
Earnings and Dividends Per Share [Abstract]
Earnings per Share	Earnings and Dividends per Share Earnings per Share The Company has unvested restricted stock units outstanding that are considered participating securities and, therefore, computes basic and diluted earnings per share under the two-class method. Basic earnings per share for the periods are based upon the weighted average number of shares of common stock outstanding during each period. Diluted earnings per share include the effects of certain stock options and performance stock units. Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Net income attributable to Westlake Chemical Corporation $ 607 $ 57 $ 1,371 $ 217 Less: Net income attributable to participating securities (3) — (7) (1) Net income attributable to common shareholders $ 604 $ 57 $ 1,364 $ 216 The following table reconciles the denominator for the basic and diluted earnings per share computations shown in the consolidated statements of operations: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Weighted average common shares—basic 128,060,193 127,701,340 128,053,337 127,872,434 Plus incremental shares from: Assumed exercise of options and vesting of performance stock units 705,621 252,567 656,760 200,632 Weighted average common shares—diluted 128,765,814 127,953,907 128,710,097 128,073,066 Earnings per common share attributable to Westlake Chemical Corporation: Basic $ 4.71 $ 0.45 $ 10.65 $ 1.69 Diluted $ 4.69 $ 0.45 $ 10.60 $ 1.69 Excluded from the computation of diluted earnings per share are options to purchase 426,918 and 1,298,659 shares of common stock for the three months ended September 30, 2021 and 2020, respectively; and 476,162 and 1,234,126 shares of common stock for the nine months ended September 30, 2021 and 2020, respectively. These options were outstanding during the periods reported but were excluded because the effect of including them would have been antidilutive. Dividends per Share Dividends per common share for the three and nine months ended September 30, 2021 and 2020 were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Dividends per common share $ 0.2975 $ 0.2700 $ 0.8375 $ 0.7950

Supplemental Information (Notes

Supplemental Information (Notes)	9 Months Ended
Supplemental Information (Notes)	Sep. 30, 2021
Supplemental Cash Flow Information [Abstract]
Supplemental Information	Supplemental Information Equity Method Investments LACC, LLC The Company's investment in LACC, LLC ("LACC"), a related party, was $947 and $961 at September 30, 2021 and December 31, 2020, respectively. The Company made capital contributions to LACC of $10 and $17 during the three and nine months ended September 30, 2021, respectively. Accrued and Other Liabilities Accrued and other liabilities were $912 and $821 at September 30, 2021 and December 31, 2020, respectively. Accrued rebates, a component of accrued and other liabilities, was $152 at September 30, 2021, and $128 at December 31, 2020. No other component of accrued and other liabilities was more than five percent of total current liabilities. Accrued liabilities with related parties were $30 and $61 at September 30, 2021 and December 31, 2020, respectively. Restructuring, Transaction and Integration-Related Costs For the three and nine months ended September 30, 2021, the restructuring, transaction and integration-related costs of $6 primarily consisted of integration-related consulting fees and costs associated with Company's recent acquisitions. For the three and nine months ended September 30, 2020, the restructuring, transaction and integration-related costs of $34 and $36, respectively, primarily consisted of restructuring expenses related to the closure of a non-integrated plant located in Germany. Non-cash Investing Activity The change in capital expenditure accruals increasing additions to property, plant and equipment was $14 and $49 for t

Commitments and Contingencies (

Commitments and Contingencies (Notes)	9 Months Ended
Commitments and Contingencies (Notes)	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies The Company is involved in a number of legal and regulatory matters, principally environmental in nature, that are incidental to the normal conduct of its business, including lawsuits, investigations and claims. The outcome of these matters are inherently unpredictable. The Company believes that, in the aggregate, the outcome of all known legal and regulatory matters will not have a material adverse effect on its consolidated financial statements; however, under certain circumstances, if required to recognize costs in a specific period, when combined with other factors, outcomes with respect to such matters may be material to the Company's consolidated statements of operations in such period. The Company's assessment of the potential impact of environmental matters, in particular, is subject to uncertainty due to the complex, ongoing and evolving process of investigation and remediation of such environmental matters, and the potential for technological and regulatory developments. In addition, the impact of evolving claims and programs, such as natural resource damage claims, industrial site reuse initiatives and state remediation programs creates further uncertainty of the ultimate resolution of these matters. The Company anticipates that the resolution of many legal and regulatory matters, and in particular environmental matters, will occur over an extended period of time. Antitrust Proceedings. The Company and other caustic soda producers were named as defendants in multiple purported class action civil lawsuits filed since March 2019 in the U.S. District Court for the Western District of New York. The lawsuits allege the defendants conspired to fix, raise, maintain and stabilize the price of caustic soda, restrict domestic (U.S.) supply of caustic soda and allocate caustic soda customers. The other defendants named in the lawsuits are Olin Corporation, K.A. Steel Chemicals (a wholly-owned subsidiary of Olin), Occidental Petroleum Corporation, Occidental Chemical Corporation d/b/a OxyChem, Shin-Etsu Chemical Co., Ltd., Shintech Incorporated, Formosa Plastics Corporation, and Formosa Plastics Corporation, U.S.A. Each of the lawsuits is filed on behalf of the respective named plaintiff or plaintiffs and a putative class comprised of either direct purchasers or indirect purchasers of caustic soda in the U.S. The plaintiffs seek an unspecified amount of damages and injunctive relief. The defendants' joint motion to dismiss the direct purchaser lawsuits was denied and the cases have proceeded to discovery. Beginning in October 2020, similar class action proceedings were also filed in Canada before the Superior Court of Quebec as well as before the Federal Court. These proceedings seek the certification or authorization of a class action on behalf of all residents of Canada who purchased caustic soda (including, in one of the cases, those who merely purchased products containing caustic soda) from October 1, 2015 through the present or such date deemed appropriate by the court. At this time, the Company is not able to estimate the impact, if any, that these lawsuits could have on the Company's consolidated financial statements either in the current period or in future periods. Environmental. As of September 30, 2021 and December 31, 2020, the Company had reserves for environmental contingencies totaling approximately $55 and $53, respectively, most of which was classified as noncurrent liabilities. The Company's assessment of the potential impact of these environmental contingencies is subject to considerable uncertainty due to the complex, ongoing and evolving process of investigation and remediation, if necessary, of such environmental contingencies, and the potential for technological and regulatory developments. Calvert City Proceedings. For several years, the Environmental Protection Agency (the "EPA") has been conducting remedial investigation and feasibility studies at the Company's Calvert City, Kentucky facility pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 ("CERCLA"). As the current owner of the Calvert City facility, the Company was named by the EPA as a potentially responsible party ("PRP") along with Goodrich Corporation ("Goodrich") and its successor-in-interest, Avient Corporation (formerly known as PolyOne Corporation, "Avient"). On November 30, 2017, the EPA published a draft Proposed Plan, incorporating by reference an August 2015 draft Remedial Investigation ("RI") report, an October 2017 draft Feasibility Study ("FS") report and a Technical Impracticability Waiver document dated December 19, 2017. On June 18, 2018, the EPA published an amendment to its Proposed Plan. The amended Proposed Plan describes a final remedy for the onshore portion of the site comprised of a containment wall, targeted treatment and supplemental hydraulic containment. The amended Proposed Plan also describes an interim approach to address the contamination under the river that would include recovery of any mobile contaminants by an extraction well along with further study of the extent of the contamination and potential treatment options. The EPA's estimated cost of implementation is $107, with an estimated $1 to $3 in annual operation and maintenance ("O&M") costs. In September 2018, the EPA published the Record of Decision ("ROD") for the site, formally selecting the preferred final and interim remedies outlined in the amended Proposed Plan. In October 2018, the EPA issued Special Notice letters to the PRPs for the remedial design phase of work under the ROD. In April 2019, the PRPs and the EPA entered into an administrative settlement agreement and order on consent for remedial design. In October 2019, the PRPs received special notice letters for the remedial action phase of work at the site. The Company, jointly with the other PRPs, submitted a good faith offer response in December 2019. On September 17, 2020, the EPA and the Department of Justice filed a proposed consent decree for the remedial action with the U.S. District Court for the Western District of Kentucky. On November 16, 2020, the Department of Justice filed a motion to approve and enter the consent decree. On January 28, 2021, the Court granted the unopposed motion to enter the consent decree, which became effective the same day. The Company's allocation of liability for remedial and O&M costs at the Calvert City site, if any, is governed by a series of agreements between the Company, Goodrich and Avient. These agreements and the associated litigation are described below. In connection with the 1990 and 1997 acquisitions of the Goodrich chemical manufacturing complex in Calvert City, Goodrich agreed to indemnify the Company for any liabilities related to preexisting contamination at the complex. For its part, the Company agreed to indemnify Goodrich for post-closing contamination caused by the Company's operations. The soil and groundwater at the complex, which does not include the Company's nearby PVC facility, had been extensively contaminated by Goodrich's operations. In 1993, Goodrich spun off the predecessor of Avient, and that predecessor assumed Goodrich's indemnification obligations relating to preexisting contamination. In 2003, litigation arose among the Company, Goodrich and Avient with respect to the allocation of the cost of remediating contamination at the site. The parties settled this litigation in December 2007 and the case was dismissed. In the settlement, the parties agreed that, among other things: (1) Avient would pay 100% of the costs (with specified exceptions), net of recoveries or credits from third parties, incurred with respect to environmental issues at the Calvert City site from August 1, 2007 forward; and (2) either the Company or Avient might, from time to time in the future (but not more than once every five years), institute an arbitration proceeding to adjust that percentage. In May 2017, Avient filed a demand for arbitration. In this proceeding, Avient sought to readjust the percentage allocation of future costs and to recover approximately $11 from the Company in reimbursement of previously paid remediation costs. The Company's cross demand for arbitration seeking unreimbursed remediation costs incurred during the relevant period was dismissed from the proceedings when Avient paid such costs in full at the beginning of the arbitration hearing. On July 10, 2018, Avient sued the Company in the U.S. District Court for the Western District of Kentucky, and sought to invalidate the arbitration provisions in the parties' 2007 settlement agreement and enjoin the arbitration it had initiated in 2017. On July 30, 2018, the district court refused to enjoin the arbitration and, on January 15, 2019, the court granted the Company's motion to dismiss Avient's suit. On February 13, 2019, Avient appealed those decisions to the U.S. Court of Appeals for the Sixth Circuit. The court of appeals issued an opinion and final order on September 6, 2019, affirming the district court. The arbitration hearing began in August 2018 and concluded in December 2018. On May 22, 2019, the arbitration panel issued its final award. It determined that Avient was responsible for 100% of the allocable costs at issue in the proceeding and that Avient would remain responsible for 100% of the costs to operate the existing groundwater remedy at the Calvert City site. In August 2019, Avient filed a motion to vacate before the U.S. District Court for the Western District of Kentucky, seeking to invalidate the final award under the Federal Arbitration Act. On February 11, 2020, the U.S. District Court for the Western District of Kentucky denied Avient's motion to vacate and affirmed the arbitration final award. Avient did not file a notice of appeal before the March 10, 2020 deadline to contest the court's decision. Accordingly, the final award was affirmed and the arbitration proceeding is fully and finally resolved. At this time, the Company is not able to estimate the impact, if any, that any subsequent arbitration or judicial proceeding could have on the Company's consolidated financial statements either in the current period or in later periods. Any cash expenditures that the Company might incur in the future with respect to the remediation of contamination at the Calvert City complex would likely be spread out over an extended period. As a result, the Company believes it is unlikely that any remediation costs allocable to it will be material in terms of expenditures made in any individual reporting period. Environmental Remediation: Reasonably Possible Matters. The Company's assessment of the potential impact of environmental contingencies is subject to considerable uncertainty due to the complex, ongoing and evolving process of investigation and remediation, if necessary, of such environmental contingencies, and the potential for technological and regulatory developments. As such, in addition to the amounts currently reserved, the Company may be subject to reasonably possible loss contingencies related to environmental matters in the range of $65 to $130.

Segment Information (Notes)

Segment Information (Notes)	9 Months Ended
Segment Information (Notes)	Sep. 30, 2021
Segment Reporting [Abstract]
Segment Information	Segment Information The Company operates in two principal operating segments: Vinyls and Olefins. These segments are strategic business units that offer a variety of different products. The Company manages each segment separately as each business requires different technology and marketing strategies. Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Net external sales Vinyls PVC, caustic soda and other $ 1,834 $ 1,116 $ 4,950 $ 3,333 Building products 514 413 1,406 1,049 Total Vinyls 2,348 1,529 6,356 4,382 Olefins Polyethylene 559 302 1,488 914 Styrene, feedstock and other 148 67 427 243 Total Olefins 707 369 1,915 1,157 $ 3,055 $ 1,898 $ 8,271 $ 5,539 Intersegment sales Vinyls $ — $ — $ — $ 1 Olefins 163 79 447 183 $ 163 $ 79 $ 447 $ 184 Income (loss) from operations Vinyls $ 601 $ 42 $ 1,236 $ 135 Olefins 281 51 738 138 Corporate and other (21) (14) (47) (22) $ 861 $ 79 $ 1,927 $ 251 Depreciation and amortization Vinyls $ 166 $ 160 $ 486 $ 467 Olefins 36 34 109 104 Corporate and other 1 2 5 6 $ 203 $ 196 $ 600 $ 577 Other income, net Vinyls $ 10 $ 7 $ 27 $ 21 Olefins — 1 2 2 Corporate and other 3 4 6 9 $ 13 $ 12 $ 35 $ 32 Provision for (benefit from) income taxes Vinyls $ 141 $ (25) $ 279 $ (121) Olefins 66 4 170 41 Corporate and other (14) 6 (26) 5 $ 193 $ (15) $ 423 $ (75) Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Capital expenditures Vinyls $ 124 $ 94 $ 346 $ 338 Olefins 19 16 66 60 Corporate and other 1 2 2 5 $ 144 $ 112 $ 414 $ 403 A reconciliation of total segment income from operations to consolidated income before income taxes is as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Income from operations $ 861 $ 79 $ 1,927 $ 251 Interest expense (61) (37) (130) (108) Other income, net 13 12 35 32 Income before income taxes $ 813 $ 54 $ 1,832 $ 175 September 30, December 31, Total assets Vinyls $ 11,655 $ 10,680 Olefins 2,153 1,923 Corporate and other 3,300 1,232 $ 17,108 $ 13,835

Westlake Chemical Partners LP (

Westlake Chemical Partners LP (Notes)	9 Months Ended
Westlake Chemical Partners LP (Notes)	Sep. 30, 2021
Partners' Capital [Abstract]
Westlake Chemical Partners LP	Westlake Chemical Partners LP In 2014, the Company formed Westlake Chemical Partners LP ("Westlake Partners") to operate, acquire and develop ethylene production facilities and related assets. Also in 2014, Westlake Partners completed its initial public offering of 12,937,500 common units. At September 30, 2021, Westlake Partners had a 22.8% limited partner interest in Westlake Chemical OpCo LP ("OpCo"), and the Company retained a 77.2% limited partner interest in OpCo and a significant interest in Westlake Partners through the Company's ownership of Westlake Partners' general partner, 40.1% of the limited partner interests (consisting of 14,122,230 common units) and incentive distribution rights. On October 4, 2018, Westlake Partners and Westlake Partners GP, the general partner of Westlake Partners, entered into an Equity Distribution Agreement with UBS Securities LLC, Barclays Capital Inc., Citigroup Global Markets Inc., Deutsche Bank Securities Inc., RBC Capital Markets, LLC, Merrill Lynch, Pierce, Fenner & Smith Incorporated and Wells Fargo Securities, LLC to offer and sell Westlake Partners' common units, from time to time, up to an aggregate offering amount of $50. This Equity Distribution Agreement was amended on February 28, 2020 to reference a new shelf registration for utilization under this agreement. No common units were issued under this program as of September 30, 2021.

Basis of Financial Statements_2

Basis of Financial Statements (Policies)	9 Months Ended
Basis of Financial Statements (Policies)	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Financial Statements	The accompanying unaudited consolidated interim financial statements were prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the "SEC") for interim periods. Accordingly, certain information and footnotes required for complete financial statements under generally accepted accounting principles in the United States ("U.S. GAAP") have not been included. These interim consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto of Westlake Chemical Corporation (the "Company") included in the annual report on Form 10-K for the fiscal year ended December 31, 2020 (the "2020 Form 10-K"), filed with the SEC on February 24, 2021. These consolidated financial statements have been prepared in conformity with the accounting principles and practices as disclosed in the notes to the consolidated financial statements of the Company for the fiscal year ended December 31, 2020. In the opinion of the Company's management, the accompanying unaudited consolidated interim financial statements reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for a fair statement of the Company's financial position as of September 30, 2021, its results of operations for the three and nine months ended September 30, 2021 and 2020, and the changes in its cash position for the nine months ended September 30, 2021 and 2020.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Reference Rate Reform (ASU No. 2020-04) In March 2020, the Financial Accounting Standards Board ("FASB") issued an accounting standards update to provide optional expedients and exceptions for applying generally accepted accounting principles to contracts, hedging relationships and other transactions affected by reference rate reform, if certain criteria are met. The amendments in this update are effective for all entities from March 12, 2020 through December 31, 2022, and the adoption is not expected to have a material impact on our consolidated financial statements. Certain exceptions provided under this guidance may be applicable to future reference rate reform related transitions. Recently Adopted Accounting Standards Income Taxes (ASU No. 2019-12) In December 2019, the FASB issued an accounting standards update removing certain exceptions for investments, intraperiod allocations and interim calculations and adding guidance to reduce complexity in accounting for income taxes. The accounting standard became effective for reporting periods beginning after December 15, 2020. The Company adopted this accounting standard effective January 1, 2021, and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows.

Accounts Receivable (Tables)

Accounts Receivable (Tables)	9 Months Ended
Accounts Receivable (Tables)	Sep. 30, 2021
Accounts Receivable, after Allowance for Credit Loss [Abstract]
Schedule Of Accounts Receivable	Accounts receivable consist of the following: September 30, December 31, Trade customers $ 1,553 $ 1,086 Related parties 2 9 Allowance for credit losses (23) (17) 1,532 1,078 Federal and state taxes 49 92 Other 61 44 Accounts receivable, net $ 1,642 $ 1,214

Inventories (Tables)

Inventories (Tables)	9 Months Ended
Inventories (Tables)	Sep. 30, 2021
Inventory Disclosure [Abstract]
Schedule Of Inventory	Inventories consist of the following: September 30, December 31, Finished products $ 639 $ 524 Feedstock, additives, chemicals and other raw materials 316 227 Materials and supplies 169 167 Inventories $ 1,124 $ 918

Goodwill (Tables)

Goodwill (Tables)	9 Months Ended
Goodwill (Tables)	Sep. 30, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The gross carrying amounts and changes in the carrying amount of goodwill for the nine months ended September 30, 2021 were as follows: Vinyls Segment Olefins Segment Total Balances at December 31, 2020 $ 1,053 $ 30 $ 1,083 Goodwill acquired during the period 172 — 172 Effects of changes in foreign exchange rates (2) — (2) Balances at September 30, 2021 $ 1,223 $ 30 $ 1,253

Accounts Payable (Tables)

Accounts Payable (Tables)	9 Months Ended
Accounts Payable (Tables)	Sep. 30, 2021
Accounts Payable [Abstract]
Schedule of Accounts Payable and Accrued Liabilities	Accounts payable consist of the following: September 30, December 31, Accounts payable—third parties $ 687 $ 529 Accounts payable to related parties 17 — Notes payable 14 7 Accounts payable $ 718 $ 536

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended
Long-Term Debt (Tables)	Sep. 30, 2021
Debt Disclosure [Abstract]
Schedule Of Long-Term Debt	Long-term debt consists of the following: September 30, 2021 December 31, 2020 Principal Unamortized Net Principal Unamortized Net 3.60% senior notes due 2022 (the "3.60% 2022 Senior Notes") $ 250 $ — $ 250 $ 250 $ (1) $ 249 0.875% senior notes due 2024 (the "0.875% 2024 Senior Notes") 300 (2) 298 — — — 3.60% senior notes due 2026 (the "3.60% 2026 Senior Notes") 750 (6) 744 750 (6) 744 Loan related to tax-exempt waste disposal revenue bonds due 2027 11 11 11 — 11 1.625% senior notes due 2029 (the "1.625% 2029 Senior Notes") 811 (9) 802 859 (10) 849 3.375% senior notes due 2030 (the "3.375% 2030 Senior Notes") 300 (4) 296 300 (4) 296 3.50% senior notes due 2032 (the "3.50% 2032 GO Zone Refunding Senior Notes") 250 (1) 249 250 (1) 249 2.875% senior notes due 2041 (the "2.875% 2041 Senior Notes") 350 (11) 339 — — — 5.0% senior notes due 2046 (the "5.0% 2046 Senior Notes") 700 (22) 678 700 (23) 677 4.375% senior notes due 2047 (the "4.375% 2047 Senior Notes") 500 (8) 492 500 (9) 491 3.125% senior notes due 2051 (the "3.125% 2051 Senior Notes") 600 (23) 577 — — — 3.375% senior notes due 2061 (the "3.375% 2061 Senior Notes") 450 (19) 431 — — — 8.73% RS Cogen debt due 2022 (the "8.73% 2022 RS Cogen Debt") 24 24 — — — Term loans due 2026 (the "2026 Term Loans") 6 — 6 — — — Total long-term debt 5,302 (105) 5,197 3,620 (54) 3,566 Less current portion: 3.60% 2022 Senior Notes (250) — (250) — — — 8.73% 2022 RS Cogen Debt (18) — (18) — — — Long-term debt, net of current portion $ 5,034 $ (105) $ 4,929 $ 3,620 $ (54) $ 3,566

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
Accumulated Other Comprehensive Income (Loss) (Tables)	Sep. 30, 2021
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	Changes in accumulated other comprehensive income (loss) by component for the nine months ended September 30, 2021 and 2020 were as follows: Pension and Other Post-Retirement Benefits Cumulative Total Balances at December 31, 2020 $ (24) $ (40) $ (64) Other comprehensive loss attributable to Westlake Chemical Corporation — (11) (11) Balances at September 30, 2021 $ (24) $ (51) $ (75) Balances at December 31, 2019 $ 3 $ (77) $ (74) Other comprehensive income attributable to Westlake Chemical Corporation — 5 5 Balances at September 30, 2020 $ 3 $ (72) $ (69)

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
Fair Value Measurements (Tables)	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Summary Of Carrying And Fair Values Of Long-Term Debt	The carrying and fair values of the Company's long-term debt are summarized in the table below. September 30, 2021 December 31, 2020 Carrying Fair Carrying Fair 3.60% 2022 Senior Notes $ 250 $ 254 $ 249 $ 259 0.875% 2024 Senior Notes 298 301 — — 3.60% 2026 Senior Notes 744 825 744 846 Loan related to tax-exempt waste disposal revenue bonds due 2027 11 11 11 11 1.625% 2029 Senior Notes 802 860 849 897 3.375% 2030 Senior Notes 296 325 296 332 3.50% 2032 GO Zone Refunding Senior Notes 249 276 249 276 2.875% 2041 Senior Notes 339 337 — — 5.0% 2046 Senior Notes 678 872 677 905 4.375% 2047 Senior Notes 492 577 491 597 3.125% 2051 Senior Notes 577 571 — — 3.375% 2061 Senior Notes 431 427 — — 8.73% 2022 RS Cogen Debt 24 24 — — 2026 Term Loans 6 6 — —

Earnings and Dividends per Sh_2

Earnings and Dividends per Share (Tables)	9 Months Ended
Earnings and Dividends per Share (Tables)	Sep. 30, 2021
Earnings and Dividends Per Share [Abstract]
Schedule Of Net Income Attributable To Common Stockholders	Diluted earnings per share include the effects of certain stock options and performance stock units. Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Net income attributable to Westlake Chemical Corporation $ 607 $ 57 $ 1,371 $ 217 Less: Net income attributable to participating securities (3) — (7) (1) Net income attributable to common shareholders $ 604 $ 57 $ 1,364 $ 216
Reconciliation Of Denominator For Basic And Diluted Earnings Per Share	The following table reconciles the denominator for the basic and diluted earnings per share computations shown in the consolidated statements of operations: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Weighted average common shares—basic 128,060,193 127,701,340 128,053,337 127,872,434 Plus incremental shares from: Assumed exercise of options and vesting of performance stock units 705,621 252,567 656,760 200,632 Weighted average common shares—diluted 128,765,814 127,953,907 128,710,097 128,073,066 Earnings per common share attributable to Westlake Chemical Corporation: Basic $ 4.71 $ 0.45 $ 10.65 $ 1.69 Diluted $ 4.69 $ 0.45 $ 10.60 $ 1.69
Dividends Per Share	Dividends per Share Dividends per common share for the three and nine months ended September 30, 2021 and 2020 were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Dividends per common share $ 0.2975 $ 0.2700 $ 0.8375 $ 0.7950

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
Segment Information (Tables)	Sep. 30, 2021
Segment Reporting [Abstract]
Segment Reporting Information	Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Net external sales Vinyls PVC, caustic soda and other $ 1,834 $ 1,116 $ 4,950 $ 3,333 Building products 514 413 1,406 1,049 Total Vinyls 2,348 1,529 6,356 4,382 Olefins Polyethylene 559 302 1,488 914 Styrene, feedstock and other 148 67 427 243 Total Olefins 707 369 1,915 1,157 $ 3,055 $ 1,898 $ 8,271 $ 5,539 Intersegment sales Vinyls $ — $ — $ — $ 1 Olefins 163 79 447 183 $ 163 $ 79 $ 447 $ 184 Income (loss) from operations Vinyls $ 601 $ 42 $ 1,236 $ 135 Olefins 281 51 738 138 Corporate and other (21) (14) (47) (22) $ 861 $ 79 $ 1,927 $ 251 Depreciation and amortization Vinyls $ 166 $ 160 $ 486 $ 467 Olefins 36 34 109 104 Corporate and other 1 2 5 6 $ 203 $ 196 $ 600 $ 577 Other income, net Vinyls $ 10 $ 7 $ 27 $ 21 Olefins — 1 2 2 Corporate and other 3 4 6 9 $ 13 $ 12 $ 35 $ 32 Provision for (benefit from) income taxes Vinyls $ 141 $ (25) $ 279 $ (121) Olefins 66 4 170 41 Corporate and other (14) 6 (26) 5 $ 193 $ (15) $ 423 $ (75) Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Capital expenditures Vinyls $ 124 $ 94 $ 346 $ 338 Olefins 19 16 66 60 Corporate and other 1 2 2 5 $ 144 $ 112 $ 414 $ 403
Reconciliation Of Total Segment Income From Operations To Consolidated Income Before Income Taxes	A reconciliation of total segment income from operations to consolidated income before income taxes is as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Income from operations $ 861 $ 79 $ 1,927 $ 251 Interest expense (61) (37) (130) (108) Other income, net 13 12 35 32 Income before income taxes $ 813 $ 54 $ 1,832 $ 175
Total Assets	September 30, December 31, Total assets Vinyls $ 11,655 $ 10,680 Olefins 2,153 1,923 Corporate and other 3,300 1,232 $ 17,108 $ 13,835

Basis of Financial Statements_3

Basis of Financial Statements (Details)	Sep. 30, 2021
RS Cogen
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Noncontrolling interest, ownership percentage	50.00%
Entergy
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	50.00%

Acquisitions (Details)

Acquisitions (Details) - USD ($) $ in Millions	Oct. 01, 2021	Sep. 10, 2021	Aug. 19, 2021	Sep. 30, 2021
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Goodwill acquired during the period				$ 172
Boral Target Companies \| Subsequent Event
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Payments to acquire business	$ 2,150
Business Combination, Contingent Consideration, Liability, Noncurrent	$ 65
Lasco Fittings, Inc.
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Total purchase consideration			$ 277
Intangible assets			77
Goodwill acquired during the period			106
Lasco Fittings, Inc. \| Customer Relationships
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Intangible assets			$ 50
Lasco Fittings, Inc. \| Minimum
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Finite-lived intangible asset useful life			17 years
Lasco Fittings, Inc. \| Maximum
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Finite-lived intangible asset useful life			18 years
Dimex, LLC
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Total purchase consideration		$ 172
Intangible assets		69
Goodwill acquired during the period		66
Dimex, LLC \| Customer Relationships
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Intangible assets		$ 45
Dimex, LLC \| Minimum
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Finite-lived intangible asset useful life		17 years
Dimex, LLC \| Maximum
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Finite-lived intangible asset useful life		19 years

Financial Instruments (Narrativ

Financial Instruments (Narrative) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Restricted Cash and Cash Equivalents	$ 39	$ 24

Accounts Receivable (Details)

Accounts Receivable (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Accounts Receivable, after Allowance for Credit Loss [Abstract]
Trade customers	$ 1,553	$ 1,086
Related parties	2	9
Allowance for credit losses	(23)	(17)
Accounts receivable from trade customers, net	1,532	1,078
Federal and state taxes	49	92
Other	61	44
Accounts receivable, net	$ 1,642	$ 1,214

Inventories (Details)

Inventories (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Finished products	$ 639	$ 524
Feedstock, additives, chemicals and other raw materials	316	227
Materials and supplies	169	167
Inventories	$ 1,124	$ 918

Goodwill (Details)

Goodwill (Details) $ in Millions	9 Months Ended
Goodwill (Details) $ in Millions	Sep. 30, 2021USD ($)
Goodwill [Roll Forward]
Beginning Balance	$ 1,083
Goodwill acquired during the period	172
Effects of changes in foreign exchange rates	(2)
Ending Balance	1,253
Olefins
Goodwill [Roll Forward]
Beginning Balance	30
Goodwill acquired during the period	0
Effects of changes in foreign exchange rates	0
Ending Balance	30
Vinyls
Goodwill [Roll Forward]
Beginning Balance	1,053
Goodwill acquired during the period	172
Effects of changes in foreign exchange rates	(2)
Ending Balance	$ 1,223

Accounts Payable (Details)

Accounts Payable (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Accounts Payable [Abstract]
Accounts payable—third parties	$ 687	$ 529
Accounts payable to related parties	17	0
Notes payable	14	7
Accounts payable	$ 718	$ 536

Long-Term Debt (Schedule of Lon

Long-Term Debt (Schedule of Long-term Debt) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Aug. 19, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Principal Amount	$ 5,302		$ 3,620
Unamortized Discount and Debt Issuance Costs	(105)		(54)
Net Long-term Debt	5,197		3,566
Long-term Debt, Current Maturities	(268)		0
Debt Instrument Unamortized Discount Premium and Debt Issuance Cost Net Excluding Current Maturities	(105)		(54)
Long term Debt Gross Excluding Current Maturities	5,034		3,620
Long-term debt, net of current portion	$ 4,929		3,566
Senior Notes \| 3.60% Senior Notes Due 2022
Debt Instrument [Line Items]
Stated interest rate (percent)	3.60%
Principal Amount	$ 250		250
Unamortized Discount and Debt Issuance Costs	0		(1)
Net Long-term Debt	250		249
Debt Instrument Unamortized Discount Premium and debt issuance cost net Current Maturities	0		0
Long Term Debt Gross Current Maturities	(250)		0
Long-term Debt, Current Maturities	$ (250)		0
Senior Notes \| 0.875% Senior Notes Due 2024
Debt Instrument [Line Items]
Stated interest rate (percent)	0.875%	0.875%
Principal Amount	$ 300		0
Unamortized Discount and Debt Issuance Costs	(2)		0
Net Long-term Debt	$ 298		0
Senior Notes \| 3.6% Senior Notes Due 2026
Debt Instrument [Line Items]
Stated interest rate (percent)	3.60%
Principal Amount	$ 750		750
Unamortized Discount and Debt Issuance Costs	(6)		(6)
Net Long-term Debt	744		744
Senior Notes \| Loan related to tax-exempt waste disposal revenue bonds due 2027
Debt Instrument [Line Items]
Principal Amount	11		11
Unamortized Discount and Debt Issuance Costs			0
Net Long-term Debt	$ 11		11
Senior Notes \| 1.625% Senior Notes Due 2029
Debt Instrument [Line Items]
Stated interest rate (percent)	1.625%
Principal Amount	$ 811		859
Unamortized Discount and Debt Issuance Costs	(9)		(10)
Net Long-term Debt	$ 802		849
Senior Notes \| 3.375% Senior Notes Due 2030
Debt Instrument [Line Items]
Stated interest rate (percent)	3.375%
Principal Amount	$ 300		300
Unamortized Discount and Debt Issuance Costs	(4)		(4)
Net Long-term Debt	$ 296		296
Senior Notes \| 3.50% Senior Notes Due 2032
Debt Instrument [Line Items]
Stated interest rate (percent)	3.50%
Principal Amount	$ 250		250
Unamortized Discount and Debt Issuance Costs	(1)		(1)
Net Long-term Debt	$ 249		249
Senior Notes \| 2.875% Senior Notes Due 2041
Debt Instrument [Line Items]
Stated interest rate (percent)	2.875%	2.875%
Principal Amount	$ 350		0
Unamortized Discount and Debt Issuance Costs	(11)		0
Net Long-term Debt	$ 339		0
Senior Notes \| 5.0% Senior Notes Due 2046
Debt Instrument [Line Items]
Stated interest rate (percent)	5.00%
Principal Amount	$ 700		700
Unamortized Discount and Debt Issuance Costs	(22)		(23)
Net Long-term Debt	$ 678		677
Senior Notes \| 4.375% Senior Notes Due 2047
Debt Instrument [Line Items]
Stated interest rate (percent)	4.375%
Principal Amount	$ 500		500
Unamortized Discount and Debt Issuance Costs	(8)		(9)
Net Long-term Debt	$ 492		491
Senior Notes \| 8.73% Senior Notes Due 2022
Debt Instrument [Line Items]
Stated interest rate (percent)	8.73%
Principal Amount	$ 24		0
Unamortized Discount and Debt Issuance Costs			0
Net Long-term Debt	24		0
Debt Instrument Unamortized Discount Premium and debt issuance cost net Current Maturities	0		0
Long Term Debt Gross Current Maturities	(18)		0
Long-term Debt, Current Maturities	$ (18)		0
Senior Notes \| Term Loan Due 2026
Debt Instrument [Line Items]
Stated interest rate (percent)	0.20%
Principal Amount	$ 6		0
Unamortized Discount and Debt Issuance Costs	0		0
Net Long-term Debt	$ 6		0
Senior Notes \| 3.125% Senior Notes Due 2051
Debt Instrument [Line Items]
Stated interest rate (percent)	3.125%	3.125%
Principal Amount	$ 600		0
Unamortized Discount and Debt Issuance Costs	(23)		0
Net Long-term Debt	$ 577		0
Senior Notes \| 3.75% Senior Notes Due 2061
Debt Instrument [Line Items]
Stated interest rate (percent)	3.375%	3.375%
Principal Amount	$ 450		0
Unamortized Discount and Debt Issuance Costs	(19)		0
Net Long-term Debt	$ 431		$ 0

Long-Term Debt (Credit Agreemen

Long-Term Debt (Credit Agreement) (Details) - USD ($) $ in Millions	Jul. 24, 2018	Sep. 30, 2021	Aug. 19, 2021
Credit Agreement \| Line of Credit \| Minimum
Debt Instrument [Line Items]
Line of credit permitted increase	$ 25
Credit Agreement \| Line of Credit \| Maximum
Debt Instrument [Line Items]
Line of credit permitted increase	500
Credit Agreement \| Revolving Credit Facility
Debt Instrument [Line Items]
Remaining borrowing capacity		$ 1,000
Credit Agreement \| Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity		1,000
Borrowing outstanding		0
Outstanding letters of credit		$ 0
Credit Agreement \| Letter of Credit \| Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity	150
Credit Agreement \| Swingline Loan \| Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 50
Credit Agreement \| Alternate Base Rate [Domain] \| Revolving Credit Facility \| Line of Credit \| Minimum
Debt Instrument [Line Items]
Spread on variable rate	0.00%
Credit Agreement \| Alternate Base Rate [Domain] \| Revolving Credit Facility \| Line of Credit \| Maximum
Debt Instrument [Line Items]
Spread on variable rate	0.75%
Credit Agreement \| London Interbank Offered Rate (LIBOR) \| Revolving Credit Facility \| Line of Credit \| Minimum
Debt Instrument [Line Items]
Spread on variable rate	1.00%
Credit Agreement \| London Interbank Offered Rate (LIBOR) \| Revolving Credit Facility \| Line of Credit \| Maximum
Debt Instrument [Line Items]
Spread on variable rate	1.75%
3.125% Senior Notes Due 2051 \| Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount			$ 600

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended
	Mar. 31, 2021	Sep. 30, 2021	Aug. 19, 2021	Dec. 31, 2020	Jul. 31, 2000
Debt Instrument [Line Items]
Unamortized debt issuance cost		$ 43		$ 28
RS Cogen
Debt Instrument [Line Items]
Noncontrolling interest, ownership percentage		50.00%
Senior Notes \| 8.73% Senior Notes Due 2022
Debt Instrument [Line Items]
Stated interest rate (percent)		8.73%
Senior Notes \| Term Loan Due 2026
Debt Instrument [Line Items]
Stated interest rate (percent)		0.20%
Maximum borrowing capacity		$ 23
Debt instrument term	5 years
Senior Notes \| Term Loan Due 2026 \| Taiwan Chlorine Industries, Ltd.
Debt Instrument [Line Items]
Noncontrolling interest, ownership percentage		60.00%
Senior Notes \| 0.875% Senior Notes Due 2024
Debt Instrument [Line Items]
Stated interest rate (percent)		0.875%	0.875%
Aggregate principal amount			$ 300
Senior Notes \| 2.875% Senior Notes Due 2041
Debt Instrument [Line Items]
Stated interest rate (percent)		2.875%	2.875%
Aggregate principal amount			$ 350
Senior Notes \| 3.75% Senior Notes Due 2061
Debt Instrument [Line Items]
Stated interest rate (percent)		3.375%	3.375%
Aggregate principal amount			$ 450
Line of Credit \| 8.73% Senior Notes Due 2022 \| RS Cogen
Debt Instrument [Line Items]
Stated interest rate (percent)		8.73%
Noncontrolling interest, ownership percentage		50.00%
Maximum borrowing capacity					$ 75

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) (Schedule of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 6,043
Ending balance	7,298
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(24)	$ 3
Net other comprehensive income (loss) attributable to Westlake Chemical Corporation	0	0
Ending balance	(24)	3
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(40)	(77)
Net other comprehensive income (loss) attributable to Westlake Chemical Corporation	(11)	5
Ending balance	(51)	(72)
Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(64)	(74)
Net other comprehensive income (loss) attributable to Westlake Chemical Corporation	(11)	5
Ending balance	$ (75)	$ (69)

Fair Value Measurements (Summar

Fair Value Measurements (Summary of Carrying and Fair Values of Long Term Debt) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Aug. 19, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 5,197		$ 3,566
3.60% Senior Notes Due 2022 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 250		249
Stated interest rate (percent)	3.60%
3.6% Senior Notes Due 2026 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 744		744
Stated interest rate (percent)	3.60%
Loan related to tax-exempt waste disposal revenue bonds due 2027 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 11		11
1.625% Senior Notes Due 2029 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 802		849
Stated interest rate (percent)	1.625%
3.375% Senior Notes Due 2030 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 296		296
Stated interest rate (percent)	3.375%
3.50% Senior Notes Due 2032 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 249		249
Stated interest rate (percent)	3.50%
5.0% Senior Notes Due 2046 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 678		677
Stated interest rate (percent)	5.00%
4.375% Senior Notes Due 2047 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 492		491
Stated interest rate (percent)	4.375%
8.73% Senior Notes Due 2022 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 24		0
Stated interest rate (percent)	8.73%
Term Loan Due 2026 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 6		0
Stated interest rate (percent)	0.20%
0.875% Senior Notes Due 2024 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 298		0
Stated interest rate (percent)	0.875%	0.875%
2.875% Senior Notes Due 2041 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 339		0
Stated interest rate (percent)	2.875%	2.875%
3.125% Senior Notes Due 2051 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 577		0
Stated interest rate (percent)	3.125%	3.125%
3.75% Senior Notes Due 2061 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 431		0
Stated interest rate (percent)	3.375%	3.375%
Fair Value [Member] \| 3.60% Senior Notes Due 2022 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	$ 254		259
Fair Value [Member] \| 3.6% Senior Notes Due 2026 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	825		846
Fair Value [Member] \| Loan related to tax-exempt waste disposal revenue bonds due 2027 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	11		11
Fair Value [Member] \| 1.625% Senior Notes Due 2029 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	860		897
Fair Value [Member] \| 3.375% Senior Notes Due 2030 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	325		332
Fair Value [Member] \| 3.50% Senior Notes Due 2032 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	276		276
Fair Value [Member] \| 5.0% Senior Notes Due 2046 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	872		905
Fair Value [Member] \| 4.375% Senior Notes Due 2047 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	577		597
Fair Value [Member] \| 8.73% Senior Notes Due 2022 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	24		0
Fair Value [Member] \| Term Loan Due 2026 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	6		0
Fair Value [Member] \| 0.875% Senior Notes Due 2024 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	301		0
Fair Value [Member] \| 2.875% Senior Notes Due 2041 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	337		$ 0
Fair Value [Member] \| 3.125% Senior Notes Due 2051 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	571
Fair Value [Member] \| 3.75% Senior Notes Due 2061 \| Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	$ 427

Income Taxes (Details)

Income Taxes (Details)	3 Months Ended		9 Months Ended
Income Taxes (Details)	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Effective income tax rate	23.70%	(27.80%)	23.10%	(42.90%)
U.S. federal statutory income tax rate	21.00%	21.00%	21.00%	21.00%

Earnings and Dividends per Sh_3

Earnings and Dividends per Share (Schedule of Net Income Attributable to Common Stockholders) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings and Dividends Per Share [Abstract]
Net income attributable to Westlake Chemical Corporation	$ 607	$ 57	$ 1,371	$ 217
Net income attributable to participating securities	(3)	0	(7)	(1)
Net income attributable to common shareholders	$ 604	$ 57	$ 1,364	$ 216

Earnings and Dividends per Sh_4

Earnings and Dividends per Share (Reconciliation of Denominator for Basic and Diluted Earnings Per Share) (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings and Dividends Per Share [Abstract]
Weighted average common shares—basic	128,060,193	127,701,340	128,053,337	127,872,434
Weighted Average Number Diluted Shares Outstanding Adjustment	705,621	252,567	656,760	200,632
Weighted average common shares-diluted	128,765,814	127,953,907	128,710,097	128,073,066
Earnings per share attributable to Westlake Chemical Corporation: Basic (in dollars per share)	$ 4.71	$ 0.45	$ 10.65	$ 1.69
Earnings per share attributable to Westlake Chemical Corporation: Diluted (in dollars per share)	$ 4.69	$ 0.45	$ 10.60	$ 1.69

Earnings and Dividends per Sh_5

Earnings and Dividends per Share (Additional Information) (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings and Dividends Per Share [Abstract]
Number of options excluded from computation of diluted earnings per share	426,918	1,298,659	476,162	1,234,126

Earnings and Dividends per Sh_6

Earnings and Dividends per Share Dividends Per Share (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings and Dividends Per Share [Abstract]
Dividends per common share (in usd per share)	$ 0.2975	$ 0.2700	$ 0.8375	$ 0.7950

Supplemental Information (Equit

Supplemental Information (Equity Method Investments) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Dec. 31, 2020
Schedule of Equity Method Investments [Line Items]
Payments to Acquire Interest in Subsidiaries and Affiliates	$ 10	$ 17
LACC, LLC
Schedule of Equity Method Investments [Line Items]
Investments in and Advances to Affiliates, at Fair Value	$ 947	$ 947	$ 961

Supplemental Information (Addit

Supplemental Information (Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Accrued Liabilities and Other Liabilities [Abstract]
Accrued and other liabilities	$ 912		$ 912		$ 821
Accrued rebates	152		152		128
Accrued liabilities with related parties	30		30		$ 61
Noncash Investing and Financing Items [Abstract]
Restructuring, transaction and integration-related costs	$ 6	$ 34	6	$ 36
Accruals for Capital Expenditure			$ (14)	$ (49)

Commitments and Contingencies_2

Commitments and Contingencies (Additional Information) (Detail) - USD ($) $ in Millions	May 22, 2019	Jun. 18, 2018	May 31, 2017	Sep. 30, 2021	Dec. 31, 2020
Environmental Loss Contingencies [Line Items]
Environmental Loss contingency accrual				$ 55	$ 53
Site Contingency, Percentage of Cost Potentially of Other Responsible Parties [Line Items]				100.00%
Avient
Environmental Loss Contingencies [Line Items]
Site Contingency, Percentage of Cost Potentially of Other Responsible Parties [Line Items]	100.00%
Avient \| Pending Litigation
Environmental Loss Contingencies [Line Items]
Loss Contingency, Damages Sought, Value			$ 11
Minimum
Environmental Loss Contingencies [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss				$ 65
Maximum
Environmental Loss Contingencies [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss				130
EPA \| Operation and Maintenance
Environmental Loss Contingencies [Line Items]
Environmental Remediation Expense		$ 107
EPA \| Operation and Maintenance \| Minimum
Environmental Loss Contingencies [Line Items]
Environmental Exit Costs, Anticipated Cost				1
EPA \| Operation and Maintenance \| Maximum
Environmental Loss Contingencies [Line Items]
Environmental Exit Costs, Anticipated Cost				$ 3

Segment Information (Additional

Segment Information (Additional Information) (Detail)	9 Months Ended
Segment Information (Additional Information) (Detail)	Sep. 30, 2021Segment
Segment Reporting [Abstract]
Number of segments	2

Segment Information (Segment Re

Segment Information (Segment Reporting Information) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Net sales	$ 3,055	$ 1,898	$ 8,271	$ 5,539
Income (loss) from operations	861	79	1,927	251
Depreciation and amortization	203	196	600	577
Other income, net	13	12	35	32
Provision for (benefit from) income taxes	193	(15)	423	(75)
Capital expenditures	144	112	414	403
Operating Segments [Member] \| Olefins
Segment Reporting Information [Line Items]
Net sales	707	369	1,915	1,157
Income (loss) from operations	281	51	738	138
Depreciation and amortization	36	34	109	104
Other income, net	0	1	2	2
Provision for (benefit from) income taxes	66	4	170	41
Capital expenditures	19	16	66	60
Operating Segments [Member] \| Vinyls
Segment Reporting Information [Line Items]
Net sales	2,348	1,529	6,356	4,382
Income (loss) from operations	601	42	1,236	135
Depreciation and amortization	166	160	486	467
Other income, net	10	7	27	21
Provision for (benefit from) income taxes	141	(25)	279	(121)
Capital expenditures	124	94	346	338
Operating Segments [Member] \| Polyethylene [Member] \| Olefins
Segment Reporting Information [Line Items]
Net sales	559	302	1,488	914
Operating Segments [Member] \| Styrene, Feedstock And Other [Member] \| Olefins
Segment Reporting Information [Line Items]
Net sales	148	67	427	243
Operating Segments [Member] \| PVC, Caustic Soda And Other [Member] \| Vinyls
Segment Reporting Information [Line Items]
Net sales	1,834	1,116	4,950	3,333
Operating Segments [Member] \| Building Products [Member] \| Vinyls
Segment Reporting Information [Line Items]
Net sales	514	413	1,406	1,049
Corporate and other [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations	(21)	(14)	(47)	(22)
Depreciation and amortization	1	2	5	6
Other income, net	3	4	6	9
Provision for (benefit from) income taxes	(14)	6	(26)	5
Capital expenditures	1	2	2	5
Intersegment sales [Member]
Segment Reporting Information [Line Items]
Net sales	163	79	447	184
Intersegment sales [Member] \| Olefins
Segment Reporting Information [Line Items]
Net sales	163	79	447	183
Intersegment sales [Member] \| Vinyls
Segment Reporting Information [Line Items]
Net sales	$ 0	$ 0	$ 0	$ 1

Segment Information (Reconcilia

Segment Information (Reconciliation of Total Segment Income from Operations to Consolidated Income before Income Taxes) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting [Abstract]
Income from operations	$ 861	$ 79	$ 1,927	$ 251
Interest expense	(61)	(37)	(130)	(108)
Other income (expense), net	13	12	35	32
Income before income taxes	$ 813	$ 54	$ 1,832	$ 175

Segment Information (Total Asse

Segment Information (Total Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 17,108	$ 13,835
Operating Segments [Member] \| Olefins
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	2,153	1,923
Operating Segments [Member] \| Vinyls
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	11,655	10,680
Corporate and other [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 3,300	$ 1,232

Westlake Chemical Partners LP_2

Westlake Chemical Partners LP (Details) - USD ($) $ in Millions	Oct. 04, 2018	Sep. 30, 2021	Dec. 31, 2015
Related Party Transaction [Line Items]
Partners' Capital Account, Units, Sold in Public Offering			12,937,500
Partners' Units, Maximum Aggregate Offering Amount, ATM	$ 50
Westlake Chemical OpCo LP [Member] \| Subsidiary of Common Parent [Member] \| Limited Partner [Member]
Related Party Transaction [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest		22.80%
Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest		77.20%
Westlake Chemical Partners LP [Member] \| Subsidiary of Common Parent [Member] \| Limited Partner [Member]
Related Party Transaction [Line Items]
Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest		40.10%
Ownership interest (in units)		14,122,230