Westlake (WLK) 10-Q 3 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	Apr. 26, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Trading Symbol	WLK
Entity Registrant Name	WESTLAKE CHEMICAL CORP
Entity Central Index Key	1,262,823
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		129,594,582

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 851	$ 1,531
Accounts receivable, net	1,135	1,001
Inventories	944	900
Prepaid expenses and other current assets	29	31
Total current assets	2,959	3,463
Property, plant and equipment, net	6,447	6,412
Goodwill	1,010	1,012
Customer relationships, net	594	616
Other intangible assets, net	160	161
Other assets, net	434	412
Total assets	11,604	12,076
Current liabilities
Accounts payable	596	600
Accrued liabilities	596	657
Current portion of long-term debt	461	710
Total current liabilities	1,653	1,967
Long-term debt, net	2,666	3,127
Deferred income taxes	1,125	1,111
Pension and other post-retirement benefits	342	344
Other liabilities	177	158
Total liabilities	5,963	6,707
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 March 31, 2018 and December 31, 2017, respectively	1	1
Common stock, held in treasury, at cost; 5,057,732 and 5,232,875 shares at March 31, 2018 and December 31, 2017, respectively	(292)	(302)
Additional Paid in Capital	555	555
Retained earnings	4,874	4,613
Accumulated other comprehensive income	3	7
Total Westlake Chemical Corporation stockholders' equity	5,141	4,874
Noncontrolling interests	500	495
Total equity	5,641	5,369
Total liabilities and equity	$ 11,604	$ 12,076

Consolidated Balance Sheets (U3

Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Mar. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
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 issued	0	0
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

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Net sales	$ 2,150	$ 1,943
Cost of sales	1,608	1,577
Gross profit	542	366
Selling, general and administrative expenses	108	99
Amortization of Intangible Assets	26	25
Transaction and integration-related costs	7	8
Income (loss) from operations	401	234
Other income (expense)
Interest expense	(37)	(40)
Other income, net	22	7
Income before income taxes	386	201
Provision for income taxes	89	56
Net income	297	145
Net income attributable to noncontrolling interests	10	7
Net income attributable to Westlake Chemical Corporation	$ 287	$ 138
Earnings per common share attributable to Westlake Chemical Corporation:
Basic (usd per share)	$ 2.21	$ 1.07
Diluted (usd per share)	$ 2.20	$ 1.06
Weighted average common shares outstanding:
Basic (in shares)	129,483,968	128,979,357
Diluted (in shares)	130,190,892	129,692,015
Dividends per common share (usd per share)	$ 0.21	$ 0.1906

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 297	$ 145
Foreign Currency Translation Adjustment, by Component [Abstract]
Foreign currency translation	(6)	19
Income tax benefit (provision) on foreign currency translation	4	(2)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(2)	17
Comprehensive income	295	162
Comprehensive income attributable to noncontrolling interests, net of tax of $1 and $1 for the three months ended March 31, 2018 and 2017, respectively	12	6
Comprehensive income attributable to Westlake Chemical Corporation	$ 283	$ 156

Consolidated Statements of Com6

Consolidated Statements of Comprehensive Income (Unaudited) OCI Parenthetical - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
OCI Parenthetical [Abstract]
Other Comprehensive Income (Loss), Tax, Portion Attributable to Noncontrolling Interest	$ 1	$ 1

Consolidated Statements Of Chan

Consolidated Statements Of Changes In Stockholders' Equity Statement - USD ($) $ in Millions	Total	Common Stock [Member]	Common Stock, Held in Treasury [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]
Beginning balances at Dec. 31, 2016	$ 3,892	$ 1	$ 319	$ 551	$ 3,412	$ (121)	$ 368
Beginning balance, shares issued at Dec. 31, 2016		134,651,380
Beginning balance, Treasury shares at Dec. 31, 2016			5,726,377
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	145				138		7
Other comprehensive income (loss)	20					17	3
Shares issued—stock- based compensation (in shares)			(118,065)
Shares issued—stock- based compensation	1		$ 3	(2)
Stock-based compensation, net of tax on stock options exercised	3			3
Dividends declared	(24)				(24)
Distributions to noncontrolling interests	(4)						(4)
Ending balances at Mar. 31, 2017	4,033	$ 1	$ 316	552	3,526	(104)	374
Ending balance, shares issued at Mar. 31, 2017		134,651,380
Ending balance, Treasury shares at Mar. 31, 2017			5,608,312
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of accounting change	1				1
Beginning balances at Dec. 31, 2017	5,369	$ 1	$ (302)	555	4,613	7	495
Beginning balance, shares issued at Dec. 31, 2017		134,651,380
Beginning balance, Treasury shares at Dec. 31, 2017			5,232,875
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	297				287		10
Other comprehensive income (loss)	(2)					(4)	2
Shares issued—stock- based compensation (in shares)			(175,143)
Shares issued—stock- based compensation	6		$ 10	(4)
Stock-based compensation, net of tax on stock options exercised	4			4
Dividends declared	(27)				(27)
Distributions to noncontrolling interests	(7)						(7)
Ending balances at Mar. 31, 2018	$ 5,641	$ 1	$ (292)	$ 555	$ 4,874	$ 3	$ 500
Ending balance, shares issued at Mar. 31, 2018		134,651,380
Ending balance, Treasury shares at Mar. 31, 2018			5,057,732

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities
Net income	$ 297	$ 145
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	156	150
Stock-based compensation expense	6	6
Loss from disposition of property, plant and equipment	6	3
Deferred income taxes	16	(6)
Other gains, net	(7)	0
Changes in operating assets and liabilities
Accounts receivable	(133)	(65)
Inventories	(41)	(19)
Prepaid expenses and other current assets	2	6
Accounts payable	(13)	49
Accrued liabilities	(48)	(122)
Other, net	(16)	10
Net cash provided by operating activities	225	157
Cash flows from investing activities
Additions to property, plant and equipment	(154)	(134)
Additions to investments in unconsolidated subsidiaries	(26)	(15)
Other	2	1
Net cash used for investing activities	(178)	(148)
Cash flows from financing activities
Dividends paid	(27)	(24)
Distributions to noncontrolling interests	(7)	(4)
Proceeds from debt issuance and drawdown of revolver	4	52
Repayment of term loan	0	(150)
Repayment of revolver	0	(125)
Repayment of notes payable	(706)	(2)
Other	5	0
Net cash used for financing activities	(731)	(253)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	4	3
Net decrease in cash, cash equivalents and restricted cash	(680)	(241)
Cash, cash equivalents and restricted cash at beginning of period	1,554	646
Cash, cash equivalents and restricted cash at end of period	$ 874	$ 405

Basis of Financial Statements

Basis of Financial Statements	3 Months Ended
	Mar. 31, 2018
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 December 31, 2017 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, 2017 (the " 2017 Form 10-K"), filed with the SEC on February 21, 2018 . 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, 2017 with the exception of those accounting standards adopted in the first quarter of 2018 as discussed in Note 1. 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 March 31, 2018 , its results of operations for the three months ended March 31, 2018 and 2017 and the changes in its cash position for the three months ended March 31, 2018 and 2017 . 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, 2018 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. Certain reclassifications have been made to the prior-year financial statements to conform to the current-year presentation. Recent Accounting Pronouncements Leases (ASU No. 2016-02) In February 2016, the Financial Accounting Standards Board ("FASB") issued an accounting standards update on a new lease standard that will supersede the existing lease guidance. The standard requires a lessee to recognize assets and liabilities related to long-term leases that are classified as operating leases under current guidance on its balance sheet. An asset would be recognized related to the right to use the underlying asset and a liability would be recognized related to the obligation to make lease payments over the term of the lease. The standard also requires expanded disclosures related to leases. The accounting standard will be effective for reporting periods beginning after December 15, 2018. The Company is in the process of evaluating the impact that the new accounting guidance will have on the Company's consolidated financial position, results of operations and cash flows. Credit Losses (ASU No. 2016-13) In June 2016, the FASB issued an accounting standards update providing new guidance for the accounting for credit losses on loans and other financial instruments. The new guidance introduces an approach based on expected losses to estimate credit losses on certain types of financial instruments. The standard also modifies the impairment model for available-for-sale debt securities and provides for a simplified accounting model for purchased financial assets with credit deterioration since their origination. The accounting standard will be effective for reporting periods beginning after December 15, 2019 and is not expected to have a material impact on the Company's consolidated financial position, results of operations and cash flows. Intangibles - Goodwill and Other (ASU No. 2017-04) In January 2017, the FASB issued an accounting standards update to simplify the subsequent measurement of goodwill. The guidance removes Step 2 of the goodwill impairment test, which requires a hypothetical purchase price allocation. A goodwill impairment will now be the amount by which a reporting unit's carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. The accounting standard will be effective for reporting periods beginning after December 15, 2019 and is not expected to have a material impact on the Company's consolidated financial position, results of operations and cash flows. Income Statement - Reporting Comprehensive Income (ASU 2018-02) In February 2018, the FASB issued an accounting standards update to (1) allow reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the U.S. Tax Cuts and Jobs Act (the "Tax Act"); and (2) require certain disclosures about stranded tax effects. The accounting standard will be effective for reporting periods beginning after December 15, 2018. Early adoption is permitted. The Company is in the process of evaluating the impact that the new accounting guidance will have on the Company's consolidated financial position, results of operations and cash flows. Recently Adopted Accounting Standards Revenue from Contracts with Customers (ASU No. 2014-09) In May 2014, the FASB issued an accounting standards update on a comprehensive new revenue recognition standard that supersedes virtually all previously issued revenue recognition guidance. The new accounting guidance creates a framework by which an entity will allocate the transaction price to separate performance obligations and recognize revenue when each performance obligation is satisfied. Under the new standard, entities are required to use judgment and make estimates, including identifying performance obligations in a contract, estimating the amount of variable consideration to include in the transaction price, allocating the transaction price to each separate performance obligation and determining when an entity satisfies its performance obligations. The standard allows for "modified retrospective" adoption, meaning the standard is applied only to the most current period presented in the financial statements with a cumulative catch-up as of the current period. The Company adopted ASU No. 2014-09, Revenue from Contracts with Customers ("ASC 606"), effective January 1, 2018. The Company applied the modified retrospective transition method to all contracts that were not completed as of the adoption date. Periods prior to January 1, 2018 were not adjusted and are reported under the accounting standards that were in place during those periods. The cumulative effects of changes to the Company’s consolidated January 1, 2018 balance sheet for the adoption of this accounting standard were immaterial. The impact of ASC 606 adoption on the financial statements for the three months ended March 31, 2017 as compared with the guidance that was in effect prior to January 1, 2018 was immaterial. Revenue is recognized when the Company transfers control of inventories to its customers. Amounts recognized as revenues reflect the consideration to which the Company expects to be entitled in exchange for those inventories. Provisions for discounts, rebates and returns are incorporated in the estimate of variable consideration and reflected as reduction to revenue in the same period as the related sales. Control of inventories generally transfers upon shipment for domestic sales. The Company excludes taxes collected on behalf of customers from the estimated contract price. For export contracts, the point at which control passes to the customer varies depending on the terms specified in the customer contract. The Company generally invoices customers and recognizes revenue and accounts receivable upon transferring control of inventories. In limited circumstances, the Company transfers control of inventories shortly before it has an unconditional right to receive consideration, resulting in recognition of contract assets. The Company also receives advance payments from certain customers, resulting in recognition of contract liabilities. Contract assets and liabilities are generally settled within the period and are not material to the consolidated balance sheets. The Company expenses sales commissions when incurred. These costs are recorded within selling, general and administrative expenses. The Company does not disclose the value of unsatisfied performance obligations because its contracts with customers (i) have an original expected duration of one year or less or (ii) have only variable consideration that is calculated based on market prices at specified dates and is allocated to wholly unsatisfied performance obligations. ASC 606 requires disclosure of disaggregated revenue into categories that depict the nature of how the Company's revenue and cash flows are affected by economic factors. The Company discloses revenues by product and segment in Note 13 to this quarterly report on Form 10-Q. Recognition and Measurement of Financial Assets and Financial Liabilities (ASU No. 2016-01) In January 2016, the FASB issued an accounting standards update making certain changes principally to the current guidance for equity investments, financial liabilities under the fair value option and the presentation and disclosure requirements for financial instruments. Among other things, the guidance (1) requires equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value, with changes in fair value recognized in net income; (2) allows entities to elect to measure equity investments without readily determinable fair values at cost, less impairment, adjusted for subsequent observable price changes (changes in the basis of these equity investments to be reported in net income); (3) requires an entity that has elected the fair value option for financial liabilities to recognize changes in fair value due to instrument-specific credit risk separately in other comprehensive income; (4) clarified current guidance related to the valuation allowance assessment when recognizing deferred tax assets resulting from unrealized losses on available-for-sale debt securities; and (5) requires specific disclosure pertaining to financial assets and financial liabilities in the financial statements. The accounting standard became effective for reporting periods beginning after December 15, 2017. The Company adopted this accounting standard effective January 1, 2018 and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows. The Company is party to a joint venture investment with Lotte Chemical USA Corporation to build an ethylene facility, LACC, LLC ("LACC"). The Company measures its investment in LACC at cost, adjusted for observable price changes, because the investment does not have a readily determinable fair value. Cash Flows (ASU No. 2016-15) In August 2016, the FASB issued an accounting standards update providing new guidance on the classification of certain cash receipts and payments including debt extinguishment costs, debt prepayment costs, settlement of zero-coupon debt instruments, contingent consideration payments, proceeds from the settlement of insurance claims and life insurance policies and distributions received from equity method investees in the statement of cash flows. This update is required to be applied using the retrospective transition method to each period presented unless it is impracticable to be applied retrospectively. In such situation, this guidance is to be applied prospectively. The accounting standard became effective for reporting periods beginning after December 15, 2017. The Company adopted this accounting standard effective January 1, 2018 and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows. Cash Flows (ASU No. 2016-18) In November 2016, the FASB issued an accounting standards update to clarify certain existing principles in Accounting Standards Codification ("ASC") 230, Cash flows, including providing additional guidance related to transfers between cash and restricted cash and how entities present, in their statement of cash flows, the cash receipts and cash payments that directly affect the restricted cash accounts. The accounting standard became effective for reporting periods beginning after December 15, 2017. The Company adopted this accounting standard effective January 1, 2018. Upon adoption, the Company retrospectively adjusted its financial statements to reflect restricted cash in the beginning and ending cash and restricted cash balances within the statements of cash flows. As a result of this retrospective adoption and reclassification of restricted cash and cash equivalents, Net cash provided by (used for) financing activities on the consolidated statement of cash flows for the three months ended March 31, 2017 has been adjusted to $(253) from the originally reported $(99) to reflect the retrospective application of the new accounting guidance. Previously reported Cash and cash equivalents at beginning of the period and Cash and cash equivalents at end of the period for the three months ended March 31, 2017 have been adjusted to include restricted cash of $186 and $32 , respectively. Business Combinations (ASU No. 2017-01) In January 2017, the FASB issued an accounting standards update to assist entities with evaluating when a set of transferred assets and activities is a business. The guidance requires an entity to evaluate if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets; if so, the set of transferred assets and activities is not a business. The guidance also requires a business to include at least one substantive process and narrows the definition of outputs by more closely aligning it with how outputs are described in the ASC 606, Revenue from contracts with customers. The accounting standard became effective for reporting periods beginning after December 15, 2017. The Company adopted the accounting standard effective January 1, 2018 and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows. Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets (ASU No. 2017-05) In February 2017, the FASB issued an accounting standards update to clarify the scope of guidance related to other income — gains and losses from the derecognition of nonfinancial assets, and to add guidance for partial sales of nonfinancial assets. The new guidance clarifies that an in substance nonfinancial asset is an asset or group of assets for which substantially all of the fair value consists of nonfinancial assets and the group or subsidiary is not a business. The guidance also outlines that when an entity transfers its controlling interest in a nonfinancial asset, but retains a noncontrolling interest, it will measure the retained interest at fair value resulting in full gain or loss recognition upon sale of the controlling interest. The accounting standard became effective for reporting periods beginning after December 15, 2017. The Company adopted this accounting standard effective January 1, 2018 and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows. Compensation - Retirement Benefits (ASU No. 2017-07) In March 2017, the FASB issued an accounting standards update to improve the presentation of net periodic pension cost and net periodic postretirement benefit cost. The new guidance requires employers to disaggregate the service cost component from the other components of net periodic benefit cost and report the service cost component in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The amendments also allow only the service cost component to be eligible for capitalization when applicable. The accounting standard became effective for reporting periods beginning after December 15, 2017. The Company adopted this accounting standard effective January 1, 2018 and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows. Compensation - Stock Compensation (ASU No. 2017-09) In May 2017, the FASB issued the accounting standards update to provide clarity and reduce both (1) diversity in practice and (2) cost and complexity when applying the guidance in Topic 718, Compensation-Stock Compensation, to a change to the terms or conditions of a share-based payment award. The amendments in this update provide guidance about which changes to the terms or conditions of a share-based payment award require the application of modification accounting in Topic 718. Essentially, an entity will not have to account for the effects of a modification if: (1) the fair value of the modified award is the same immediately before and after the modification; (2) the vesting conditions of the modified award are the same immediately before and after the modification; and (3) the classification of the modified award as either an equity instrument or liability instrument is the same immediately before and after the modification. This update is to be applied prospectively to an award modified on or after the adoption date. The accounting standard became effective for reporting periods beginning after December 15, 2017. The Company adopted this accounting standard effective January 1, 2018 and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows. Derivatives and Hedging - Targeted Improvements to Accounting for Hedging Activities (ASU No. 2017-12) In August 2017, the FASB issued an accounting standards update to improve financial reporting of hedging relationships, to better portray the economic results of an entity's risk management activities in the financial statements and to simplify application of hedge accounting guidance. The accounting standard eliminates certain hedge effectiveness measurement and reporting requirements and expands the types of permissible hedging strategies. The accounting standard will be effective for reporting periods beginning after December 15, 2018, and interim periods within those fiscal years. Early application is permitted in any interim period after issuance, to be applied retrospectively to the beginning of the fiscal year. The Company adopted this accounting standard effective January 1, 2018 and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows. In January 2018, the Company entered into cross-currency swaps to reduce the volatility in stockholders' equity from changes in currency exchange rates associated with the Company's net investments in foreign operations. These cross-currency swaps were designated in a net investment hedge relationship. See Note 7 for additional information.

Financial Instruments

Financial Instruments	3 Months Ended
	Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Financial Instruments	Financial Instruments Cash Equivalents The Company had $205 and $644 of held-to-maturity securities with original maturities of three months or less, primarily consisting of corporate debt securities, classified as cash equivalents at March 31, 2018 and December 31, 2017 , respectively. The Company's investments in held-to-maturity securities were held at amortized cost, which approximates fair value. Restricted Cash and Cash Equivalents The Company had restricted cash and cash equivalents of $23 at March 31, 2018 and December 31, 2017 . The Company's restricted cash and cash equivalents are related to balances that are restricted for payment of distributions to certain of the Company's current and former employees and are reflected primarily in other assets, net in the consolidated balance sheets.

Accounts Receivable

Accounts Receivable	3 Months Ended
	Mar. 31, 2018
Accounts Receivable, Net [Abstract]
Accounts Receivable	Accounts Receivable Accounts receivable consist of the following: March 31, December 31, Trade customers $ 1,116 $ 974 Affiliates 13 9 Allowance for doubtful accounts (24 ) (22 ) 1,105 961 Federal and state taxes 4 7 Other 26 33 Accounts receivable, net $ 1,135 $ 1,001

Inventories

Inventories	3 Months Ended
	Mar. 31, 2018
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consist of the following: March 31, December 31, Finished products $ 592 $ 549 Feedstock, additives and chemicals 209 221 Materials and supplies 143 130 Inventories $ 944 $ 900

Long-Term Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt Long-term debt consists of the following: March 31, 2018 December 31, 2017 Principal Unamortized Discount Net Principal Unamortized Net 3.60% senior notes due 2022 (the "3.60% 2022 Senior Notes") $ 250 $ (1 ) $ 249 $ 250 $ (1 ) $ 249 4.875% senior notes due 2023 (the "4.875% Westlake 2023 Senior Notes") 434 11 445 434 11 445 4.875% senior notes due 2023 (the "4.875% Subsidiary 2023 Senior Notes") 16 — 16 16 — 16 3.60% senior notes due 2026 (the "3.60% 2026 Senior Notes") 750 (10 ) 740 750 (10 ) 740 Loan related to tax-exempt waste disposal revenue bonds due 2027 11 — 11 11 — 11 6 ½% senior notes due 2029 (the "6 ½% 2029 GO Zone Senior Notes") 100 (1 ) 99 100 (1 ) 99 6 ½% senior notes due 2035 (the "6 ½% 2035 GO Zone Senior Notes") 89 (1 ) 88 89 (1 ) 88 6 ½% senior notes due 2035 (the "6 ½% 2035 IKE Zone Senior Notes") 65 — 65 65 — 65 5.0% senior notes due 2046 (the "5.0% 2046 Senior Notes") 700 (25 ) 675 700 (25 ) 675 4.375% senior notes due 2047 (the "4.375% 2047 Senior Notes") 500 (9 ) 491 500 (9 ) 491 3.50% senior notes due 2032 (the "3.50% 2032 GO Zone Refunding Senior Notes") 250 (2 ) 248 250 (2 ) 248 4.625% senior notes due 2021 (the — — — 625 20 645 4.625% senior notes due 2021 — — — 63 2 65 Total Long-term debt 3,165 (38 ) 3,127 3,853 (16 ) 3,837 Less: Current portion - 4.625% Westlake 2021 Senior Notes and 4.625% Subsidiary 2021 Senior Notes — — — 688 22 710 Current portion - 4.875% Westlake 2023 Senior Notes and 4.875% Subsidiary 2023 Senior Notes 450 11 461 — — — Long-term debt, net of current portion $ 2,715 $ (49 ) $ 2,666 $ 3,165 $ (38 ) $ 3,127 Credit Agreement The Company has a $1,000 revolving credit facility that matures on August 23, 2021 (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 March 31, 2018 , the Company had no borrowings outstanding under the Credit Agreement. As of March 31, 2018 , the Company had outstanding letters of credit totaling $5 and borrowing availability of $995 under the Credit Agreement. The obligations of the Company under the Credit Agreement are guaranteed by current and future material domestic subsidiaries of the Company, subject to certain exceptions. The Credit Agreement contains certain affirmative and negative covenants, including a quarterly total leverage ratio financial maintenance covenant. The Credit Agreement also contains certain events of default and if and for so long as an event of default has occurred and is continuing, any 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. As of March 31, 2018 , the Company was in compliance with the total leverage ratio financial maintenance covenant. 4.625% Senior Notes due 2021 In December 2017, the Company delivered irrevocable notices for the optional redemption of all of the outstanding 4.625% Westlake 2021 Senior Notes and 4.625% Subsidiary 2021 Senior Notes (collectively, the "2021 Notes"). The 2021 Notes were redeemed on February 15, 2018 at a redemption price equal to 102.313% of the principal amount of the 2021 Notes plus accrued and unpaid interest on the 2021 Notes to the redemption date. The Company recognized a $6 gain in other income upon redemption of the 2021 Notes. The 2021 Notes were classified as a component of current liabilities in the consolidated balance sheet at December 31, 2017 , based on the terms of the redemption. 4.875% Senior Notes due 2023 In March 2018, the Company delivered irrevocable notices for the optional redemption of all of the outstanding 4.875% Westlake 2023 Senior Notes and 4.875% Subsidiary 2023 Senior Notes (collectively, the "2023 Notes") for redemption on May 15, 2018 at a redemption price equal to 102.438% of the principal amount of the 2023 Notes plus accrued and unpaid interest on the 2023 Notes to the redemption date. The 2023 Notes were classified as a component of current liabilities in the consolidated balance sheet at March 31, 2018, based on the terms of the redemption. As of March 31, 2018 , the Company was in compliance with all of the covenants with respect to the 3.60% 2022 Senior Notes, the 4.875% Westlake 2023 Senior Notes, the 4.875% Subsidiary 2023 Senior Notes, the 3.60% 2026 Senior Notes, the 5.0% 2046 Senior Notes, the 4.375% 2047 Senior Notes, the 6 ½% 2029 GO Zone Senior Notes, the 3.50% 2032 GO Zone Refunding Senior Notes, the 6 ½% 2035 GO Zone Senior Notes, the 6 ½% 2035 IKE Zone Senior Notes, the Credit Agreement and the waste disposal revenue bonds. Unamortized debt issuance costs on long-term debt were $26 at March 31, 2018 and December 31, 2017 .

Derivative Instruments

Derivative Instruments	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	Derivative Instruments In January 2018, the Company entered into cross-currency swaps with an aggregate notional value of 220 million euros to reduce the volatility in stockholders' equity from changes in currency exchange rates associated with the Company's net investments in foreign operations. These cross-currency swaps were designated in a net investment hedge relationship. The Company assesses hedge effectiveness of these cross-currency swaps by comparing the spot rate change in the swaps to the spot rate change in the designated net investment. For the three months ended March 31, 2018 , there was no ineffectiveness recorded with regard to the Company's qualifying net investment hedges. The fair values of derivatives designated as hedging instruments in the Company's consolidated balance sheets were as follows: Derivative Liabilities Balance Sheet Location Fair Value as of Derivatives in Net Investment Hedging Relationships March 31, December 31, Foreign exchange contracts Other liabilities $ 18 $ — The following table summarizes the effect of foreign exchange derivative instruments designated as net investment hedges in the consolidated statements of operations. Gain (Loss) Recognized in Income and Excluded from Hedge Effectiveness Three Months Ended March 31, Derivatives in Net Investment Hedging Relationships Location of Gain (Loss) Recognized in Income on Derivative 2018 2017 Foreign exchange contracts Other income, net $ 1 $ — The following table summarizes the effect of foreign exchange derivative instruments designated as net investment hedges on accumulated other comprehensive income. Gain (Loss) Recognized in Other Comprehensive Income Three Months Ended March 31, Derivatives in Net Investment Hedging Relationships 2018 2017 Foreign exchange contracts $ (14 ) $ —

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2018
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 Company has cross-currency swaps that are measured at fair value on a recurring basis. The future cash flows associated with these cross-currency swaps are discounted to present value using observable market-based inputs and published foreign exchange rates. The inputs used to measure the Company's cross-currency swaps are classified as Level 2 inputs within the fair value hierarchy. See Note 7 for the fair value of the Company's cross-currency swaps. The carrying and fair values of the Company's long-term debt (including the current portion of long-term debt) are summarized in the table below. 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. March 31, 2018 December 31, 2017 Carrying Value Fair Value Carrying Value Fair Value 3.60% 2022 Senior Notes $ 249 $ 250 $ 249 $ 255 4.875% Westlake 2023 Senior Notes (1) 445 445 445 449 4.875% Subsidiary 2023 Senior Notes (1) 16 17 16 16 3.60% 2026 Senior Notes 740 727 740 757 Loan related to tax-exempt waste disposal revenue bonds due 2027 11 11 11 11 6 ½% 2029 GO Zone Senior Notes 99 109 99 111 6 ½% 2035 GO Zone Senior Notes 88 97 88 99 6 ½% 2035 IKE Zone Senior Notes 65 71 65 74 5.0% 2046 Senior Notes 675 740 675 787 4.375% 2047 Senior Notes 491 484 491 518 3.50% 2032 GO Zone Refunding Senior Notes 248 246 248 256 4.625% Westlake 2021 Senior Notes (2) — — 645 639 4.625% Subsidiary 2021 Senior Notes (2) — — 65 65 ___________________________ (1) The 4.875% Westlake 2023 Senior Notes and 4.875% Subsidiary 2023 Senior Notes were classified as a component of current liabilities in the consolidated balance sheet at March 31, 2018 . For additional information, see Note 5. (2) The 4.625% Westlake 2021 Senior Notes and 4.625% Subsidiary 2021 Senior Notes were classified as a component of current liabilities in the consolidated balance sheet at December 31, 2017 . For additional information, see Note 5.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The effective income tax rate was 22.9% for the first quarter of 2018 as compared to the effective income tax rate of 27.9% for the first quarter of 2017. The lower tax rate in the first quarter of 2018 as compared to the first quarter of 2017 was a result of the changes enacted under the Tax Act, which was signed into law on December 22, 2017. The effective income tax rate for the first quarter of 2018 was above the U.S. federal statutory rate of 21.0% primarily due to state and foreign taxes. The effective income tax rate for the first quarter of 2017 was below the U.S. federal statutory rate of 35.0% primarily due to certain discrete adjustments, a higher domestic manufacturing deduction, depletion deductions, income attributable to noncontrolling interests, research and development credits and the foreign earnings rate differential, partially offset by state income taxes. The Tax Act, among other changes, reduced U.S. corporate income tax rate from 35% to 21%, effective January 1, 2018, and also required a one-time deemed repatriation of foreign earnings at specified rates. The accounting guidance on income taxes requires that the effect on deferred tax assets and liabilities of a change in tax rates be recognized in the period the tax rate change was enacted. The SEC staff guidance allows registrants to record provisional amounts during a measurement period when it does not have the necessary information available, prepared or analyzed (including computations) in reasonable detail to complete its accounting for the change in tax law. The measurement period ends when a company has obtained, prepared and analyzed the information necessary to finalize its accounting, but cannot extend beyond one year. The corporate income tax rate change resulted in a revaluation of the Company's deferred tax assets and liabilities. At December 31, 2017, under the above guidance, the Company made a provisional adjustment of $591 of income tax benefit in the 2017 consolidated financial statements for items that the Company could reasonably estimate such as revaluation of deferred tax assets and liabilities and a one-time U.S. tax on the mandatory deemed repatriation of the Company's post-1986 foreign earnings. The Company will continue to assess the income tax effects of the Tax Act based on further standard setting activities, any transition provisions, and changes in the facts and circumstances of the Company's tax position, during the measurement period. No measurement period adjustment was made for the three months ended March 31, 2018.

Earnings per Share

Earnings per Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Earnings 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 the periods. Diluted earnings per share includes the effect of certain stock options. Three Months Ended March 31, 2018 2017 Net income attributable to Westlake Chemical Corporation $ 287 $ 138 Less: Net income attributable to participating securities (2 ) (1 ) Net income attributable to common shareholders $ 285 $ 137 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 March 31, 2018 2017 Weighted average common shares—basic 129,483,968 128,979,357 Plus incremental shares from: Assumed exercise of options 706,924 712,658 Weighted average common shares—diluted 130,190,892 129,692,015 Earnings per common share attributable to Westlake Chemical Corporation: Basic $ 2.21 $ 1.07 Diluted $ 2.20 $ 1.06 Excluded from the computation of diluted earnings per share are options to purchase 84,673 and 437,787 shares of common stock for the three months ended March 31, 2018 and 2017 , respectively. These options were outstanding during the periods reported but were excluded because the effect of including them would have been antidilutive.

Supplemental Information

Supplemental Information	3 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Supplemental Information	Supplemental Information Accrued Liabilities Accrued liabilities were $596 and $657 at March 31, 2018 and December 31, 2017 , respectively. Accrued rebates and accrued income taxes, which are components of accrued liabilities, were $108 and $130 , respectively, at December 31, 2017 . No other component of accrued liabilities was more than five percent of total current liabilities at March 31, 2018 and December 31, 2017. Accrued liabilities with affiliates were $31 and $37 at March 31, 2018 and December 31, 2017 , respectively. Non-cash Investing Activity The change in capital expenditure accrual increasing additions to property, plant and equipment was $10 and $8 for the three months ended March 31, 2018 and 2017, respectively. Other Income, net For the three months ended March 31, 2018, other income, net included income from unconsolidated subsidiaries, gain on redemption of the 2021 Notes and interest income on cash and cash equivalents of $9 , $6 and $4 , respectively. For the three months ended March 31, 2017, other income, net included income from unconsolidated subsidiaries of $4 .

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2018
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 outcomes 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, specific outcomes with respect to such matters may be material to the Company's consolidated statements of operations in any particular period in which costs, if any, are recognized. 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. Environmental. As of March 31, 2018 and December 31, 2017 , the Company had reserves for environmental contingencies totaling approximately $49 and $49 , 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, PolyOne Corporation ("PolyOne"). 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 new Technical Impracticability Waiver document dated December 19, 2017. The draft Proposed Plan describes a preferred remedy that includes a containment wall with targeted treatment and supplemental hydraulic containment, as well as active treatment of historical groundwater contamination under the Tennessee River. The EPA has estimated that the total remedy will cost $200 to $250 with an estimated $1 to $3 in annual operation and maintenance (O&M) costs. Each PRP, including the Company, submitted comments to the Proposed Plan and associated documents. The Company’s comments also proposed alternative removal options for the groundwater contamination under the Tennessee River. EPA is reviewing all comments and developing its response to comments. The Company's allocation of liability for remedial or O&M costs, if any, will be determined by the outcome of the contractual dispute with Goodrich/PolyOne, which is the subject of a pending arbitration proceeding as 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 PolyOne, and that predecessor assumed Goodrich's indemnification obligations relating to preexisting contamination. In 2003, litigation arose among the Company, Goodrich and PolyOne 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) PolyOne 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 PolyOne 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, PolyOne filed a demand for arbitration. In this proceeding, PolyOne seeks to readjust the percentage allocation of costs and to recover approximately $17 from the Company in reimbursement of previously paid remediation costs. The Company has filed a cross demand for arbitration seeking unreimbursed remediation costs incurred during the relevant period. On October 6, 2017, PolyOne filed suit against the Company in the U.S. District Court for the Western District of Kentucky seeking for the court — instead of the arbitration panel — to resolve claims asserted by the Company in the arbitration proceedings related to reimbursement of costs incurred by the Company at the Calvert City complex. PolyOne is seeking a declaratory judgment from the court that costs claimed by the Company in the arbitration are not covered under the 2007 settlement agreement and thus are not within the jurisdiction of the arbitration panel. In response, the Company has filed a motion to dismiss asserting that PolyOne's jurisdictional claims are unfounded and that the arbitration panel has jurisdiction over Westlake's claims for cost reimbursement under the arbitration agreement contained within the 2007 settlement agreement. At this time, since the proceedings are in an early stage, the Company is not able to estimate the impact, if any, that the arbitration proceeding could have on the Company's consolidated financial statements in three months ended March 31, 2018 and later years. 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 $55 to $110 . Commitments. The Company became a party to a joint venture investment with Lotte Chemical USA Corporation to build an ethylene facility, LACC. The ethylene facility is located adjacent to the Company's vinyls facility in Lake Charles. Pursuant to the contribution and subscription agreement, the Company agreed to make a maximum capital commitment to LACC of up to $225 to fund the construction costs of the ethylene plant, which represents approximately 10% of the interests in LACC. The construction of the ethylene plant commenced in January 2016, with an anticipated start-up in 2019. As of March 31, 2018 , the Company had funded approximately $141 of the Company's portion of the construction costs of the ethylene plant.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Segment Information	Segment Information The Company operates in two principal operating segments: Olefins and Vinyls. 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 March 31, 2018 2017 Net external sales Olefins Polyethylene $ 369 $ 386 Styrene, feedstock and other 134 157 Total Olefins 503 543 Vinyls PVC, caustic soda and other 1,358 1,131 Building products 289 269 Total Vinyls 1,647 1,400 $ 2,150 $ 1,943 Intersegment sales Olefins $ 120 $ 86 Vinyls — — $ 120 $ 86 Three Months Ended March 31, 2018 2017 Income (loss) from operations Olefins $ 163 $ 180 Vinyls 266 70 Corporate and other (28 ) (16 ) $ 401 $ 234 Depreciation and amortization Olefins $ 34 $ 41 Vinyls 118 107 Corporate and other 4 2 $ 156 $ 150 Other income, net Olefins $ 2 $ 1 Vinyls 12 6 Corporate and other 8 — $ 22 $ 7 Provision for (benefit from) income taxes Olefins $ 37 $ 58 Vinyls 61 15 Corporate and other (9 ) (17 ) $ 89 $ 56 Capital expenditures Olefins $ 22 $ 25 Vinyls 130 108 Corporate and other 2 1 $ 154 $ 134 A reconciliation of total segment income from operations to consolidated income before income taxes is as follows: Three Months Ended March 31, 2018 2017 Income from operations $ 401 $ 234 Interest expense (37 ) (40 ) Other income, net 22 7 Income before income taxes $ 386 $ 201 March 31, December 31, Total assets Olefins $ 1,986 $ 2,006 Vinyls 9,081 8,853 Corporate and other 537 1,217 $ 11,604 $ 12,076

Guarantor Disclosures

Guarantor Disclosures	3 Months Ended
	Mar. 31, 2018
Guarantees [Abstract]
Guarantor Disclosures	Guarantor Disclosures The Company's payment obligations under the 4.375% 2047 Senior Notes, the 3.60% 2022 Senior Notes, the 3.60% 2026 Senior Notes, the 5.0% 2046 Senior Notes and the 4.875% Westlake 2023 Senior Notes are fully and unconditionally guaranteed by each of its current and future domestic subsidiaries that guarantee other debt of the Company or of another guarantor of those notes in excess of $5 (the "Guarantor Subsidiaries"). Each Guarantor Subsidiary is 100% owned by Westlake Chemical Corporation (the " 100% Owned Guarantor Subsidiaries"). During 2016 and 2017, the Company executed a Joinder Agreement with the Administrative Agent of the Credit Agreement, whereby certain subsidiaries of the Company were added as Guarantor Subsidiaries. These guarantees are the joint and several obligations of the Guarantor Subsidiaries. The following unaudited condensed consolidating financial information presents the financial condition, results of operations and cash flows of Westlake Chemical Corporation, the 100% Owned Guarantor Subsidiaries, and the remaining subsidiaries that do not guarantee the 4.375% 2047 Senior Notes, the 3.60% 2022 Senior Notes, the 3.60% 2026 Senior Notes, the 5.0% 2046 Senior Notes and the 4.875% Westlake 2023 Senior Notes (the "Non-Guarantor Subsidiaries"), together with consolidating eliminations necessary to present the Company's results on a consolidated basis. Condensed Consolidating Financial Information as of March 31, 2018 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Balance Sheet Current assets Cash and cash equivalents $ 412 $ 59 $ 380 $ — $ 851 Accounts receivable, net 4,076 4,651 633 (8,225 ) 1,135 Inventories — 678 266 — 944 Prepaid expenses and other current assets 88 25 19 (103 ) 29 Total current assets 4,576 5,413 1,298 (8,328 ) 2,959 Property, plant and equipment, net — 4,407 2,040 — 6,447 Goodwill — 855 155 — 1,010 Customer relationships, net — 463 131 — 594 Other intangible assets, net — 87 73 — 160 Other assets, net 11,003 793 1,304 (12,666 ) 434 Total assets $ 15,579 $ 12,018 $ 5,001 $ (20,994 ) $ 11,604 Current liabilities Accounts payable $ 7,142 $ 1,246 $ 232 $ (8,024 ) $ 596 Accrued liabilities 173 488 238 (303 ) 596 Current portion of long-term debt, net 445 16 — — 461 Total current liabilities 7,760 1,750 470 (8,327 ) 1,653 Long-term debt, net 2,655 4,183 224 (4,396 ) 2,666 Deferred income taxes — 1,042 97 (14 ) 1,125 Pension and other liabilities 23 340 156 — 519 Total liabilities 10,438 7,315 947 (12,737 ) 5,963 Total Westlake Chemical Corporation stockholders' equity 5,141 4,703 3,554 (8,257 ) 5,141 Noncontrolling interests — — 500 — 500 Total equity 5,141 4,703 4,054 (8,257 ) 5,641 Total liabilities and equity $ 15,579 $ 12,018 $ 5,001 $ (20,994 ) $ 11,604 Condensed Consolidating Financial Information as of December 31, 2017 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Balance Sheet Current assets Cash and cash equivalents $ 1,089 $ 57 $ 385 $ — $ 1,531 Accounts receivable, net 3,331 4,128 580 (7,038 ) 1,001 Inventories — 654 246 — 900 Prepaid expenses and other current assets 52 27 31 (79 ) 31 Total current assets 4,472 4,866 1,242 (7,117 ) 3,463 Property, plant and equipment, net — 4,374 2,038 — 6,412 Goodwill — 855 157 — 1,012 Customer relationships, net — 479 137 — 616 Other intangible assets, net — 88 73 — 161 Other assets, net 10,706 798 1,271 (12,363 ) 412 Total assets $ 15,178 $ 11,460 $ 4,918 $ (19,480 ) $ 12,076 Current liabilities Accounts payable $ 6,367 $ 864 $ 224 $ (6,855 ) $ 600 Accrued liabilities 189 484 246 (262 ) 657 Current portion of long-term debt, net 710 — — — 710 Total current liabilities 7,266 1,348 470 (7,117 ) 1,967 Long-term debt, net 3,034 4,242 220 (4,369 ) 3,127 Deferred income taxes — 1,026 92 (7 ) 1,111 Pension and other liabilities 4 347 151 — 502 Total liabilities 10,304 6,963 933 (11,493 ) 6,707 Total Westlake Chemical Corporation stockholders' equity 4,874 4,497 3,490 (7,987 ) 4,874 Noncontrolling interests — — 495 — 495 Total equity 4,874 4,497 3,985 (7,987 ) 5,369 Total liabilities and equity $ 15,178 $ 11,460 $ 4,918 $ (19,480 ) $ 12,076 Condensed Consolidating Financial Information for the Three Months Ended March 31, 2018 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Operations Net sales $ — $ 1,746 $ 839 $ (435 ) $ 2,150 Cost of sales — 1,405 632 (429 ) 1,608 Gross profit — 341 207 (6 ) 542 Selling, general and administrative expenses — 77 37 (6 ) 108 Amortization of intangibles — 19 7 — 26 Transaction and integration-related costs — 7 — — 7 Income from operations — 238 163 — 401 Other income (expense) Interest expense (38 ) (32 ) (11 ) 44 (37 ) Other income (expense), net 45 (8 ) 29 (44 ) 22 Income before income taxes 7 198 181 — 386 Provision for income taxes 2 63 24 — 89 Equity in net income of subsidiaries 282 — — (282 ) — Net income 287 135 157 (282 ) 297 Net income attributable to noncontrolling interests — — 10 — 10 Net income attributable to Westlake Chemical Corporation $ 287 $ 135 $ 147 $ (282 ) $ 287 Comprehensive income attributable to Westlake Chemical Corporation $ 283 $ 135 $ 145 $ (280 ) $ 283 Condensed Consolidating Financial Information for the Three Months Ended March 31, 2017 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Operations Net sales $ — $ 1,580 $ 736 $ (373 ) $ 1,943 Cost of sales — 1,362 582 (367 ) 1,577 Gross profit — 218 154 (6 ) 366 Selling, general and administrative expenses 1 73 31 (6 ) 99 Amortization of intangibles — 19 6 — 25 Transaction and integration-related costs — 8 — — 8 Income (loss) from operations (1 ) 118 117 — 234 Other income (expense) Interest expense (38 ) (46 ) (1 ) 45 (40 ) Other income (expense), net 37 3 12 (45 ) 7 Income (loss) before income taxes (2 ) 75 128 — 201 Provision for (benefit from) income taxes (5 ) 53 8 — 56 Equity in net income of subsidiaries 135 — — (135 ) — Net income 138 22 120 (135 ) 145 Net income attributable to noncontrolling interests — — 7 — 7 Net income attributable to Westlake Chemical Corporation $ 138 $ 22 $ 113 $ (135 ) $ 138 Comprehensive income attributable to Westlake Chemical Corporation $ 156 $ 5 $ 122 $ (127 ) $ 156 Condensed Consolidating Financial Information for the Three Months Ended March 31, 2018 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Cash Flows Cash flows from operating activities Net income $ 287 $ 135 $ 157 $ (282 ) $ 297 Adjustments to reconcile net income to net cash provided by operating activities Depreciation and amortization — 103 53 — 156 Deferred income taxes — 12 4 — 16 Net changes in working capital and other (220 ) (211 ) (95 ) 282 (244 ) Net cash provided by operating activities 67 39 119 — 225 Cash flows from investing activities Additions to property, plant and equipment — (122 ) (32 ) — (154 ) Additions to investments in unconsolidated subsidiaries — (16 ) (10 ) — (26 ) Other — 2 — — 2 Net cash used for investing activities — (136 ) (42 ) — (178 ) Cash flows from financing activities Intercompany financing (18 ) 2 16 — — Dividends paid (27 ) — — — (27 ) Distributions to noncontrolling interests — 97 (104 ) — (7 ) Proceeds from debt issuance and drawdown of revolver — — 4 — 4 Repayment of notes payable (704 ) — (2 ) — (706 ) Other 5 — — — 5 Net cash provided by (used for) financing activities (744 ) 99 (86 ) — (731 ) Effect of exchange rate changes on cash, cash equivalents and restricted cash — — 4 — 4 Net increase (decrease) in cash, cash equivalents and restricted cash (677 ) 2 (5 ) — (680 ) Cash, cash equivalents and restricted cash at beginning of period 1,089 79 386 — 1,554 Cash, cash equivalents and restricted cash at end of period $ 412 $ 81 $ 381 $ — $ 874 Condensed Consolidating Financial Information for the Three Months Ended March 31, 2017 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Cash Flows Cash flows from operating activities Net income $ 138 $ 22 $ 120 $ (135 ) $ 145 Adjustments to reconcile net income to net cash provided by (used for) operating activities Depreciation and amortization — 98 52 — 150 Deferred income taxes — (3 ) (3 ) — (6 ) Net changes in working capital and other (213 ) (29 ) (25 ) 135 (132 ) Net cash provided by (used for) operating activities (75 ) 88 144 — 157 Cash flows from investing activities Additions to property, plant and equipment — (121 ) (13 ) — (134 ) Additions to investments in unconsolidated subsidiaries — (15 ) — — (15 ) Other — 1 — — 1 Net cash used for investing activities — (135 ) (13 ) — (148 ) Cash flows from financing activities Intercompany financing 78 (96 ) 18 — — Dividends paid (24 ) — — — (24 ) Distributions to noncontrolling interests — 95 (99 ) — (4 ) Proceeds from debt issuance and drawdown of revolver 50 — 2 — 52 Repayment of term loan — — (150 ) — (150 ) Repayment of revolver (125 ) — — — (125 ) Repayment of notes payable — — (2 ) — (2 ) Net cash used for financing activities (21 ) (1 ) (231 ) — (253 ) Effect of exchange rate changes on cash, cash equivalents and restricted cash — — 3 — 3 Net decrease in cash, cash equivalents and restricted cash (96 ) (48 ) (97 ) — (241 ) Cash, cash equivalents and restricted cash at beginning of period 147 78 421 — 646 Cash, cash equivalents and restricted cash at end of period $ 51 $ 30 $ 324 $ — $ 405

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss) (Notes)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Comprehensive Income (Loss) Note [Text Block]	Accumulated Other Comprehensive Income (Loss) Changes in accumulated other comprehensive income (loss) by component for the three months ended March 31, 2018 and 2017 were as follows: Benefits Liability, Net of Tax Cumulative Foreign Currency Exchange, Net of Tax Total Balances at December 31, 2016 $ 29 $ (150 ) $ (121 ) Other comprehensive income before reclassifications — 17 17 Net other comprehensive income attributable — 17 17 Balances at March 31, 2017 $ 29 $ (133 ) $ (104 ) Balances at December 31, 2017 $ 43 $ (36 ) $ 7 Other comprehensive loss before reclassifications — (4 ) (4 ) Net other comprehensive loss attributable to Westlake Chemical Corporation — (4 ) (4 ) Balances at March 31, 2018 $ 43 $ (40 ) $ 3

Basis of Financial Statements (

Basis of Financial Statements (Policies)	3 Months Ended
	Mar. 31, 2018
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 December 31, 2017 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, 2017 (the " 2017 Form 10-K"), filed with the SEC on February 21, 2018 . 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, 2017 with the exception of those accounting standards adopted in the first quarter of 2018 as discussed in Note 1. 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 March 31, 2018 , its results of operations for the three months ended March 31, 2018 and 2017 and the changes in its cash position for the three months ended March 31, 2018 and 2017 . 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, 2018 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. Certain reclassifications have been made to the prior-year financial statements to conform to the current-year presentation.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Leases (ASU No. 2016-02) In February 2016, the Financial Accounting Standards Board ("FASB") issued an accounting standards update on a new lease standard that will supersede the existing lease guidance. The standard requires a lessee to recognize assets and liabilities related to long-term leases that are classified as operating leases under current guidance on its balance sheet. An asset would be recognized related to the right to use the underlying asset and a liability would be recognized related to the obligation to make lease payments over the term of the lease. The standard also requires expanded disclosures related to leases. The accounting standard will be effective for reporting periods beginning after December 15, 2018. The Company is in the process of evaluating the impact that the new accounting guidance will have on the Company's consolidated financial position, results of operations and cash flows. Credit Losses (ASU No. 2016-13) In June 2016, the FASB issued an accounting standards update providing new guidance for the accounting for credit losses on loans and other financial instruments. The new guidance introduces an approach based on expected losses to estimate credit losses on certain types of financial instruments. The standard also modifies the impairment model for available-for-sale debt securities and provides for a simplified accounting model for purchased financial assets with credit deterioration since their origination. The accounting standard will be effective for reporting periods beginning after December 15, 2019 and is not expected to have a material impact on the Company's consolidated financial position, results of operations and cash flows. Intangibles - Goodwill and Other (ASU No. 2017-04) In January 2017, the FASB issued an accounting standards update to simplify the subsequent measurement of goodwill. The guidance removes Step 2 of the goodwill impairment test, which requires a hypothetical purchase price allocation. A goodwill impairment will now be the amount by which a reporting unit's carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. The accounting standard will be effective for reporting periods beginning after December 15, 2019 and is not expected to have a material impact on the Company's consolidated financial position, results of operations and cash flows. Income Statement - Reporting Comprehensive Income (ASU 2018-02) In February 2018, the FASB issued an accounting standards update to (1) allow reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the U.S. Tax Cuts and Jobs Act (the "Tax Act"); and (2) require certain disclosures about stranded tax effects. The accounting standard will be effective for reporting periods beginning after December 15, 2018. Early adoption is permitted. The Company is in the process of evaluating the impact that the new accounting guidance will have on the Company's consolidated financial position, results of operations and cash flows. Recently Adopted Accounting Standards Revenue from Contracts with Customers (ASU No. 2014-09) In May 2014, the FASB issued an accounting standards update on a comprehensive new revenue recognition standard that supersedes virtually all previously issued revenue recognition guidance. The new accounting guidance creates a framework by which an entity will allocate the transaction price to separate performance obligations and recognize revenue when each performance obligation is satisfied. Under the new standard, entities are required to use judgment and make estimates, including identifying performance obligations in a contract, estimating the amount of variable consideration to include in the transaction price, allocating the transaction price to each separate performance obligation and determining when an entity satisfies its performance obligations. The standard allows for "modified retrospective" adoption, meaning the standard is applied only to the most current period presented in the financial statements with a cumulative catch-up as of the current period. The Company adopted ASU No. 2014-09, Revenue from Contracts with Customers ("ASC 606"), effective January 1, 2018. The Company applied the modified retrospective transition method to all contracts that were not completed as of the adoption date. Periods prior to January 1, 2018 were not adjusted and are reported under the accounting standards that were in place during those periods. The cumulative effects of changes to the Company’s consolidated January 1, 2018 balance sheet for the adoption of this accounting standard were immaterial. The impact of ASC 606 adoption on the financial statements for the three months ended March 31, 2017 as compared with the guidance that was in effect prior to January 1, 2018 was immaterial. Revenue is recognized when the Company transfers control of inventories to its customers. Amounts recognized as revenues reflect the consideration to which the Company expects to be entitled in exchange for those inventories. Provisions for discounts, rebates and returns are incorporated in the estimate of variable consideration and reflected as reduction to revenue in the same period as the related sales. Control of inventories generally transfers upon shipment for domestic sales. The Company excludes taxes collected on behalf of customers from the estimated contract price. For export contracts, the point at which control passes to the customer varies depending on the terms specified in the customer contract. The Company generally invoices customers and recognizes revenue and accounts receivable upon transferring control of inventories. In limited circumstances, the Company transfers control of inventories shortly before it has an unconditional right to receive consideration, resulting in recognition of contract assets. The Company also receives advance payments from certain customers, resulting in recognition of contract liabilities. Contract assets and liabilities are generally settled within the period and are not material to the consolidated balance sheets. The Company expenses sales commissions when incurred. These costs are recorded within selling, general and administrative expenses. The Company does not disclose the value of unsatisfied performance obligations because its contracts with customers (i) have an original expected duration of one year or less or (ii) have only variable consideration that is calculated based on market prices at specified dates and is allocated to wholly unsatisfied performance obligations. ASC 606 requires disclosure of disaggregated revenue into categories that depict the nature of how the Company's revenue and cash flows are affected by economic factors. The Company discloses revenues by product and segment in Note 13 to this quarterly report on Form 10-Q. Recognition and Measurement of Financial Assets and Financial Liabilities (ASU No. 2016-01) In January 2016, the FASB issued an accounting standards update making certain changes principally to the current guidance for equity investments, financial liabilities under the fair value option and the presentation and disclosure requirements for financial instruments. Among other things, the guidance (1) requires equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value, with changes in fair value recognized in net income; (2) allows entities to elect to measure equity investments without readily determinable fair values at cost, less impairment, adjusted for subsequent observable price changes (changes in the basis of these equity investments to be reported in net income); (3) requires an entity that has elected the fair value option for financial liabilities to recognize changes in fair value due to instrument-specific credit risk separately in other comprehensive income; (4) clarified current guidance related to the valuation allowance assessment when recognizing deferred tax assets resulting from unrealized losses on available-for-sale debt securities; and (5) requires specific disclosure pertaining to financial assets and financial liabilities in the financial statements. The accounting standard became effective for reporting periods beginning after December 15, 2017. The Company adopted this accounting standard effective January 1, 2018 and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows. The Company is party to a joint venture investment with Lotte Chemical USA Corporation to build an ethylene facility, LACC, LLC ("LACC"). The Company measures its investment in LACC at cost, adjusted for observable price changes, because the investment does not have a readily determinable fair value. Cash Flows (ASU No. 2016-15) In August 2016, the FASB issued an accounting standards update providing new guidance on the classification of certain cash receipts and payments including debt extinguishment costs, debt prepayment costs, settlement of zero-coupon debt instruments, contingent consideration payments, proceeds from the settlement of insurance claims and life insurance policies and distributions received from equity method investees in the statement of cash flows. This update is required to be applied using the retrospective transition method to each period presented unless it is impracticable to be applied retrospectively. In such situation, this guidance is to be applied prospectively. The accounting standard became effective for reporting periods beginning after December 15, 2017. The Company adopted this accounting standard effective January 1, 2018 and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows. Cash Flows (ASU No. 2016-18) In November 2016, the FASB issued an accounting standards update to clarify certain existing principles in Accounting Standards Codification ("ASC") 230, Cash flows, including providing additional guidance related to transfers between cash and restricted cash and how entities present, in their statement of cash flows, the cash receipts and cash payments that directly affect the restricted cash accounts. The accounting standard became effective for reporting periods beginning after December 15, 2017. The Company adopted this accounting standard effective January 1, 2018. Upon adoption, the Company retrospectively adjusted its financial statements to reflect restricted cash in the beginning and ending cash and restricted cash balances within the statements of cash flows. As a result of this retrospective adoption and reclassification of restricted cash and cash equivalents, Net cash provided by (used for) financing activities on the consolidated statement of cash flows for the three months ended March 31, 2017 has been adjusted to $(253) from the originally reported $(99) to reflect the retrospective application of the new accounting guidance. Previously reported Cash and cash equivalents at beginning of the period and Cash and cash equivalents at end of the period for the three months ended March 31, 2017 have been adjusted to include restricted cash of $186 and $32 , respectively. Business Combinations (ASU No. 2017-01) In January 2017, the FASB issued an accounting standards update to assist entities with evaluating when a set of transferred assets and activities is a business. The guidance requires an entity to evaluate if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets; if so, the set of transferred assets and activities is not a business. The guidance also requires a business to include at least one substantive process and narrows the definition of outputs by more closely aligning it with how outputs are described in the ASC 606, Revenue from contracts with customers. The accounting standard became effective for reporting periods beginning after December 15, 2017. The Company adopted the accounting standard effective January 1, 2018 and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows. Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets (ASU No. 2017-05) In February 2017, the FASB issued an accounting standards update to clarify the scope of guidance related to other income — gains and losses from the derecognition of nonfinancial assets, and to add guidance for partial sales of nonfinancial assets. The new guidance clarifies that an in substance nonfinancial asset is an asset or group of assets for which substantially all of the fair value consists of nonfinancial assets and the group or subsidiary is not a business. The guidance also outlines that when an entity transfers its controlling interest in a nonfinancial asset, but retains a noncontrolling interest, it will measure the retained interest at fair value resulting in full gain or loss recognition upon sale of the controlling interest. The accounting standard became effective for reporting periods beginning after December 15, 2017. The Company adopted this accounting standard effective January 1, 2018 and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows. Compensation - Retirement Benefits (ASU No. 2017-07) In March 2017, the FASB issued an accounting standards update to improve the presentation of net periodic pension cost and net periodic postretirement benefit cost. The new guidance requires employers to disaggregate the service cost component from the other components of net periodic benefit cost and report the service cost component in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The amendments also allow only the service cost component to be eligible for capitalization when applicable. The accounting standard became effective for reporting periods beginning after December 15, 2017. The Company adopted this accounting standard effective January 1, 2018 and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows. Compensation - Stock Compensation (ASU No. 2017-09) In May 2017, the FASB issued the accounting standards update to provide clarity and reduce both (1) diversity in practice and (2) cost and complexity when applying the guidance in Topic 718, Compensation-Stock Compensation, to a change to the terms or conditions of a share-based payment award. The amendments in this update provide guidance about which changes to the terms or conditions of a share-based payment award require the application of modification accounting in Topic 718. Essentially, an entity will not have to account for the effects of a modification if: (1) the fair value of the modified award is the same immediately before and after the modification; (2) the vesting conditions of the modified award are the same immediately before and after the modification; and (3) the classification of the modified award as either an equity instrument or liability instrument is the same immediately before and after the modification. This update is to be applied prospectively to an award modified on or after the adoption date. The accounting standard became effective for reporting periods beginning after December 15, 2017. The Company adopted this accounting standard effective January 1, 2018 and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows. Derivatives and Hedging - Targeted Improvements to Accounting for Hedging Activities (ASU No. 2017-12) In August 2017, the FASB issued an accounting standards update to improve financial reporting of hedging relationships, to better portray the economic results of an entity's risk management activities in the financial statements and to simplify application of hedge accounting guidance. The accounting standard eliminates certain hedge effectiveness measurement and reporting requirements and expands the types of permissible hedging strategies. The accounting standard will be effective for reporting periods beginning after December 15, 2018, and interim periods within those fiscal years. Early application is permitted in any interim period after issuance, to be applied retrospectively to the beginning of the fiscal year. The Company adopted this accounting standard effective January 1, 2018 and the adoption did not have a material impact on the Company's consolidated financial position, results of operations and cash flows. In January 2018, the Company entered into cross-currency swaps to reduce the volatility in stockholders' equity from changes in currency exchange rates associated with the Company's net investments in foreign operations. These cross-currency swaps were designated in a net investment hedge relationship. See Note 7 for additional information.

Accounts Receivable (Tables)

Accounts Receivable (Tables)	3 Months Ended
	Mar. 31, 2018
Accounts Receivable, Net [Abstract]
Schedule Of Accounts Receivable	Accounts receivable consist of the following: March 31, December 31, Trade customers $ 1,116 $ 974 Affiliates 13 9 Allowance for doubtful accounts (24 ) (22 ) 1,105 961 Federal and state taxes 4 7 Other 26 33 Accounts receivable, net $ 1,135 $ 1,001

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2018
Inventory Disclosure [Abstract]
Schedule Of Inventory	Inventories consist of the following: March 31, December 31, Finished products $ 592 $ 549 Feedstock, additives and chemicals 209 221 Materials and supplies 143 130 Inventories $ 944 $ 900

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Schedule Of Long-Term Debt	Long-term debt consists of the following: March 31, 2018 December 31, 2017 Principal Unamortized Discount Net Principal Unamortized Net 3.60% senior notes due 2022 (the "3.60% 2022 Senior Notes") $ 250 $ (1 ) $ 249 $ 250 $ (1 ) $ 249 4.875% senior notes due 2023 (the "4.875% Westlake 2023 Senior Notes") 434 11 445 434 11 445 4.875% senior notes due 2023 (the "4.875% Subsidiary 2023 Senior Notes") 16 — 16 16 — 16 3.60% senior notes due 2026 (the "3.60% 2026 Senior Notes") 750 (10 ) 740 750 (10 ) 740 Loan related to tax-exempt waste disposal revenue bonds due 2027 11 — 11 11 — 11 6 ½% senior notes due 2029 (the "6 ½% 2029 GO Zone Senior Notes") 100 (1 ) 99 100 (1 ) 99 6 ½% senior notes due 2035 (the "6 ½% 2035 GO Zone Senior Notes") 89 (1 ) 88 89 (1 ) 88 6 ½% senior notes due 2035 (the "6 ½% 2035 IKE Zone Senior Notes") 65 — 65 65 — 65 5.0% senior notes due 2046 (the "5.0% 2046 Senior Notes") 700 (25 ) 675 700 (25 ) 675 4.375% senior notes due 2047 (the "4.375% 2047 Senior Notes") 500 (9 ) 491 500 (9 ) 491 3.50% senior notes due 2032 (the "3.50% 2032 GO Zone Refunding Senior Notes") 250 (2 ) 248 250 (2 ) 248 4.625% senior notes due 2021 (the — — — 625 20 645 4.625% senior notes due 2021 — — — 63 2 65 Total Long-term debt 3,165 (38 ) 3,127 3,853 (16 ) 3,837 Less: Current portion - 4.625% Westlake 2021 Senior Notes and 4.625% Subsidiary 2021 Senior Notes — — — 688 22 710 Current portion - 4.875% Westlake 2023 Senior Notes and 4.875% Subsidiary 2023 Senior Notes 450 11 461 — — — Long-term debt, net of current portion $ 2,715 $ (49 ) $ 2,666 $ 3,165 $ (38 ) $ 3,127

Derivative Instruments (Tables)

Derivative Instruments (Tables)	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Fair Value of Derivative Instruments in Statement of Financial Position	The fair values of derivatives designated as hedging instruments in the Company's consolidated balance sheets were as follows: Derivative Liabilities Balance Sheet Location Fair Value as of Derivatives in Net Investment Hedging Relationships March 31, December 31, Foreign exchange contracts Other liabilities $ 18 $ —
Derivative Instruments, Gain (Loss)	The following table summarizes the effect of foreign exchange derivative instruments designated as net investment hedges in the consolidated statements of operations. Gain (Loss) Recognized in Income and Excluded from Hedge Effectiveness Three Months Ended March 31, Derivatives in Net Investment Hedging Relationships Location of Gain (Loss) Recognized in Income on Derivative 2018 2017 Foreign exchange contracts Other income, net $ 1 $ —
Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss)	The following table summarizes the effect of foreign exchange derivative instruments designated as net investment hedges on accumulated other comprehensive income. Gain (Loss) Recognized in Other Comprehensive Income Three Months Ended March 31, Derivatives in Net Investment Hedging Relationships 2018 2017 Foreign exchange contracts $ (14 ) $ —

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Summary Of Carrying And Fair Values Of Long-Term Debt	March 31, 2018 December 31, 2017 Carrying Value Fair Value Carrying Value Fair Value 3.60% 2022 Senior Notes $ 249 $ 250 $ 249 $ 255 4.875% Westlake 2023 Senior Notes (1) 445 445 445 449 4.875% Subsidiary 2023 Senior Notes (1) 16 17 16 16 3.60% 2026 Senior Notes 740 727 740 757 Loan related to tax-exempt waste disposal revenue bonds due 2027 11 11 11 11 6 ½% 2029 GO Zone Senior Notes 99 109 99 111 6 ½% 2035 GO Zone Senior Notes 88 97 88 99 6 ½% 2035 IKE Zone Senior Notes 65 71 65 74 5.0% 2046 Senior Notes 675 740 675 787 4.375% 2047 Senior Notes 491 484 491 518 3.50% 2032 GO Zone Refunding Senior Notes 248 246 248 256 4.625% Westlake 2021 Senior Notes (2) — — 645 639 4.625% Subsidiary 2021 Senior Notes (2) — — 65 65 ___________________________ (1) The 4.875% Westlake 2023 Senior Notes and 4.875% Subsidiary 2023 Senior Notes were classified as a component of current liabilities in the consolidated balance sheet at March 31, 2018 . For additional information, see Note 5. (2) The 4.625% Westlake 2021 Senior Notes and 4.625% Subsidiary 2021 Senior Notes were classified as a component of current liabilities in the consolidated balance sheet at December 31, 2017 . For additional information, see Note 5.

Earnings per Share (Tables)

Earnings per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Schedule Of Net Income Attributable To Common Stockholders	Diluted earnings per share includes the effect of certain stock options. Three Months Ended March 31, 2018 2017 Net income attributable to Westlake Chemical Corporation $ 287 $ 138 Less: Net income attributable to participating securities (2 ) (1 ) Net income attributable to common shareholders $ 285 $ 137
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 March 31, 2018 2017 Weighted average common shares—basic 129,483,968 128,979,357 Plus incremental shares from: Assumed exercise of options 706,924 712,658 Weighted average common shares—diluted 130,190,892 129,692,015 Earnings per common share attributable to Westlake Chemical Corporation: Basic $ 2.21 $ 1.07 Diluted $ 2.20 $ 1.06

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Segment Reporting Information	Three Months Ended March 31, 2018 2017 Net external sales Olefins Polyethylene $ 369 $ 386 Styrene, feedstock and other 134 157 Total Olefins 503 543 Vinyls PVC, caustic soda and other 1,358 1,131 Building products 289 269 Total Vinyls 1,647 1,400 $ 2,150 $ 1,943 Intersegment sales Olefins $ 120 $ 86 Vinyls — — $ 120 $ 86 Three Months Ended March 31, 2018 2017 Income (loss) from operations Olefins $ 163 $ 180 Vinyls 266 70 Corporate and other (28 ) (16 ) $ 401 $ 234 Depreciation and amortization Olefins $ 34 $ 41 Vinyls 118 107 Corporate and other 4 2 $ 156 $ 150 Other income, net Olefins $ 2 $ 1 Vinyls 12 6 Corporate and other 8 — $ 22 $ 7 Provision for (benefit from) income taxes Olefins $ 37 $ 58 Vinyls 61 15 Corporate and other (9 ) (17 ) $ 89 $ 56 Capital expenditures Olefins $ 22 $ 25 Vinyls 130 108 Corporate and other 2 1 $ 154 $ 134
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 March 31, 2018 2017 Income from operations $ 401 $ 234 Interest expense (37 ) (40 ) Other income, net 22 7 Income before income taxes $ 386 $ 201
Total Assets	March 31, December 31, Total assets Olefins $ 1,986 $ 2,006 Vinyls 9,081 8,853 Corporate and other 537 1,217 $ 11,604 $ 12,076

Guarantor Disclosures (Tables)

Guarantor Disclosures (Tables)	3 Months Ended
	Mar. 31, 2018
Guarantees [Abstract]
Condensed Consolidating Financial Information Balance Sheet	Condensed Consolidating Financial Information as of March 31, 2018 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Balance Sheet Current assets Cash and cash equivalents $ 412 $ 59 $ 380 $ — $ 851 Accounts receivable, net 4,076 4,651 633 (8,225 ) 1,135 Inventories — 678 266 — 944 Prepaid expenses and other current assets 88 25 19 (103 ) 29 Total current assets 4,576 5,413 1,298 (8,328 ) 2,959 Property, plant and equipment, net — 4,407 2,040 — 6,447 Goodwill — 855 155 — 1,010 Customer relationships, net — 463 131 — 594 Other intangible assets, net — 87 73 — 160 Other assets, net 11,003 793 1,304 (12,666 ) 434 Total assets $ 15,579 $ 12,018 $ 5,001 $ (20,994 ) $ 11,604 Current liabilities Accounts payable $ 7,142 $ 1,246 $ 232 $ (8,024 ) $ 596 Accrued liabilities 173 488 238 (303 ) 596 Current portion of long-term debt, net 445 16 — — 461 Total current liabilities 7,760 1,750 470 (8,327 ) 1,653 Long-term debt, net 2,655 4,183 224 (4,396 ) 2,666 Deferred income taxes — 1,042 97 (14 ) 1,125 Pension and other liabilities 23 340 156 — 519 Total liabilities 10,438 7,315 947 (12,737 ) 5,963 Total Westlake Chemical Corporation stockholders' equity 5,141 4,703 3,554 (8,257 ) 5,141 Noncontrolling interests — — 500 — 500 Total equity 5,141 4,703 4,054 (8,257 ) 5,641 Total liabilities and equity $ 15,579 $ 12,018 $ 5,001 $ (20,994 ) $ 11,604 Condensed Consolidating Financial Information as of December 31, 2017 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Balance Sheet Current assets Cash and cash equivalents $ 1,089 $ 57 $ 385 $ — $ 1,531 Accounts receivable, net 3,331 4,128 580 (7,038 ) 1,001 Inventories — 654 246 — 900 Prepaid expenses and other current assets 52 27 31 (79 ) 31 Total current assets 4,472 4,866 1,242 (7,117 ) 3,463 Property, plant and equipment, net — 4,374 2,038 — 6,412 Goodwill — 855 157 — 1,012 Customer relationships, net — 479 137 — 616 Other intangible assets, net — 88 73 — 161 Other assets, net 10,706 798 1,271 (12,363 ) 412 Total assets $ 15,178 $ 11,460 $ 4,918 $ (19,480 ) $ 12,076 Current liabilities Accounts payable $ 6,367 $ 864 $ 224 $ (6,855 ) $ 600 Accrued liabilities 189 484 246 (262 ) 657 Current portion of long-term debt, net 710 — — — 710 Total current liabilities 7,266 1,348 470 (7,117 ) 1,967 Long-term debt, net 3,034 4,242 220 (4,369 ) 3,127 Deferred income taxes — 1,026 92 (7 ) 1,111 Pension and other liabilities 4 347 151 — 502 Total liabilities 10,304 6,963 933 (11,493 ) 6,707 Total Westlake Chemical Corporation stockholders' equity 4,874 4,497 3,490 (7,987 ) 4,874 Noncontrolling interests — — 495 — 495 Total equity 4,874 4,497 3,985 (7,987 ) 5,369 Total liabilities and equity $ 15,178 $ 11,460 $ 4,918 $ (19,480 ) $ 12,076
Condensed Consolidating Financial Information Statement Of Operations	Condensed Consolidating Financial Information for the Three Months Ended March 31, 2018 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Operations Net sales $ — $ 1,746 $ 839 $ (435 ) $ 2,150 Cost of sales — 1,405 632 (429 ) 1,608 Gross profit — 341 207 (6 ) 542 Selling, general and administrative expenses — 77 37 (6 ) 108 Amortization of intangibles — 19 7 — 26 Transaction and integration-related costs — 7 — — 7 Income from operations — 238 163 — 401 Other income (expense) Interest expense (38 ) (32 ) (11 ) 44 (37 ) Other income (expense), net 45 (8 ) 29 (44 ) 22 Income before income taxes 7 198 181 — 386 Provision for income taxes 2 63 24 — 89 Equity in net income of subsidiaries 282 — — (282 ) — Net income 287 135 157 (282 ) 297 Net income attributable to noncontrolling interests — — 10 — 10 Net income attributable to Westlake Chemical Corporation $ 287 $ 135 $ 147 $ (282 ) $ 287 Comprehensive income attributable to Westlake Chemical Corporation $ 283 $ 135 $ 145 $ (280 ) $ 283 Condensed Consolidating Financial Information for the Three Months Ended March 31, 2017 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Operations Net sales $ — $ 1,580 $ 736 $ (373 ) $ 1,943 Cost of sales — 1,362 582 (367 ) 1,577 Gross profit — 218 154 (6 ) 366 Selling, general and administrative expenses 1 73 31 (6 ) 99 Amortization of intangibles — 19 6 — 25 Transaction and integration-related costs — 8 — — 8 Income (loss) from operations (1 ) 118 117 — 234 Other income (expense) Interest expense (38 ) (46 ) (1 ) 45 (40 ) Other income (expense), net 37 3 12 (45 ) 7 Income (loss) before income taxes (2 ) 75 128 — 201 Provision for (benefit from) income taxes (5 ) 53 8 — 56 Equity in net income of subsidiaries 135 — — (135 ) — Net income 138 22 120 (135 ) 145 Net income attributable to noncontrolling interests — — 7 — 7 Net income attributable to Westlake Chemical Corporation $ 138 $ 22 $ 113 $ (135 ) $ 138 Comprehensive income attributable to Westlake Chemical Corporation $ 156 $ 5 $ 122 $ (127 ) $ 156
Condensed Consolidating Financial Information Statement Of Cash Flows	Condensed Consolidating Financial Information for the Three Months Ended March 31, 2018 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Cash Flows Cash flows from operating activities Net income $ 287 $ 135 $ 157 $ (282 ) $ 297 Adjustments to reconcile net income to net cash provided by operating activities Depreciation and amortization — 103 53 — 156 Deferred income taxes — 12 4 — 16 Net changes in working capital and other (220 ) (211 ) (95 ) 282 (244 ) Net cash provided by operating activities 67 39 119 — 225 Cash flows from investing activities Additions to property, plant and equipment — (122 ) (32 ) — (154 ) Additions to investments in unconsolidated subsidiaries — (16 ) (10 ) — (26 ) Other — 2 — — 2 Net cash used for investing activities — (136 ) (42 ) — (178 ) Cash flows from financing activities Intercompany financing (18 ) 2 16 — — Dividends paid (27 ) — — — (27 ) Distributions to noncontrolling interests — 97 (104 ) — (7 ) Proceeds from debt issuance and drawdown of revolver — — 4 — 4 Repayment of notes payable (704 ) — (2 ) — (706 ) Other 5 — — — 5 Net cash provided by (used for) financing activities (744 ) 99 (86 ) — (731 ) Effect of exchange rate changes on cash, cash equivalents and restricted cash — — 4 — 4 Net increase (decrease) in cash, cash equivalents and restricted cash (677 ) 2 (5 ) — (680 ) Cash, cash equivalents and restricted cash at beginning of period 1,089 79 386 — 1,554 Cash, cash equivalents and restricted cash at end of period $ 412 $ 81 $ 381 $ — $ 874 Condensed Consolidating Financial Information for the Three Months Ended March 31, 2017 Westlake Chemical Corporation 100% Owned Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations Consolidated Statement of Cash Flows Cash flows from operating activities Net income $ 138 $ 22 $ 120 $ (135 ) $ 145 Adjustments to reconcile net income to net cash provided by (used for) operating activities Depreciation and amortization — 98 52 — 150 Deferred income taxes — (3 ) (3 ) — (6 ) Net changes in working capital and other (213 ) (29 ) (25 ) 135 (132 ) Net cash provided by (used for) operating activities (75 ) 88 144 — 157 Cash flows from investing activities Additions to property, plant and equipment — (121 ) (13 ) — (134 ) Additions to investments in unconsolidated subsidiaries — (15 ) — — (15 ) Other — 1 — — 1 Net cash used for investing activities — (135 ) (13 ) — (148 ) Cash flows from financing activities Intercompany financing 78 (96 ) 18 — — Dividends paid (24 ) — — — (24 ) Distributions to noncontrolling interests — 95 (99 ) — (4 ) Proceeds from debt issuance and drawdown of revolver 50 — 2 — 52 Repayment of term loan — — (150 ) — (150 ) Repayment of revolver (125 ) — — — (125 ) Repayment of notes payable — — (2 ) — (2 ) Net cash used for financing activities (21 ) (1 ) (231 ) — (253 ) Effect of exchange rate changes on cash, cash equivalents and restricted cash — — 3 — 3 Net decrease in cash, cash equivalents and restricted cash (96 ) (48 ) (97 ) — (241 ) Cash, cash equivalents and restricted cash at beginning of period 147 78 421 — 646 Cash, cash equivalents and restricted cash at end of period $ 51 $ 30 $ 324 $ — $ 405

Accumulated Other Comprehensi32

Accumulated Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	Changes in accumulated other comprehensive income (loss) by component for the three months ended March 31, 2018 and 2017 were as follows: Benefits Liability, Net of Tax Cumulative Foreign Currency Exchange, Net of Tax Total Balances at December 31, 2016 $ 29 $ (150 ) $ (121 ) Other comprehensive income before reclassifications — 17 17 Net other comprehensive income attributable — 17 17 Balances at March 31, 2017 $ 29 $ (133 ) $ (104 ) Balances at December 31, 2017 $ 43 $ (36 ) $ 7 Other comprehensive loss before reclassifications — (4 ) (4 ) Net other comprehensive loss attributable to Westlake Chemical Corporation — (4 ) (4 ) Balances at March 31, 2018 $ 43 $ (40 ) $ 3

Basis of Financial Statements A

Basis of Financial Statements Adoption Adjustments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2016
Item Effected [Line Items]
Net Cash Provided by (Used in) Financing Activities	$ (731)	$ (253)
Accounting Standards Update 2016-18 [Member]
Item Effected [Line Items]
Net Cash Provided by (Used in) Financing Activities		(99)
Restricted Cash		$ 32	$ 186

Financial Instruments (Cash Equ

Financial Instruments (Cash Equivalent) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Cash and Cash Equivalents [Abstract]
Held-to-maturity Securities	$ 205	$ 644

Financial Instruments (Restrict

Financial Instruments (Restricted Cash Equivalents) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Restricted Cash and Cash Equivalents	$ 23	$ 23

Accounts Receivable (Details)

Accounts Receivable (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Accounts Receivable, Net [Abstract]
Trade customers	$ 1,116	$ 974
Affiliates	13	9
Allowance for doubtful accounts	(24)	(22)
Accounts receivable from trade customers, net	1,105	961
Federal and state taxes	4	7
Other	26	33
Accounts receivable, net	$ 1,135	$ 1,001

Inventories (Inventories) (Deta

Inventories (Inventories) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Finished products	$ 592	$ 549
Feedstock, additives and chemicals	209	221
Materials and supplies	143	130
Inventories	$ 944	$ 900

Long-Term Debt (Schedule of Lon

Long-Term Debt (Schedule of Long-term Debt) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Principal Amount	$ 3,165	$ 3,853
Unamortized Premium (Discount) and Debt Issuance Costs	(38)	(16)
Net, Long-term Debt	3,127	3,837
Long-term Debt, Current Maturities	461	710
Long-term Debt, Gross Excluding Current Maturities	2,715	3,165
Debt Instrument, Unamortized Premium (Discount) and Debt Issuance Cost, Net, Excluding Current Maturities	(49)	(38)
Long-term Debt, Excluding Current Maturities	$ 2,666	3,127
Senior Notes [Member] | 3.60% Senior Notes Due 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,022
Stated interest rate (percent)	3.60%
Principal Amount	$ 250	250
Unamortized Premium (Discount) and Debt Issuance Costs	(1)	(1)
Net, Long-term Debt	$ 249	249
Senior Notes [Member] | 4.875% Senior Notes Due 2023 (New Westlake 2023 Notes) [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,023
Stated interest rate (percent)	4.875%
Principal Amount	$ 434	434
Unamortized Premium (Discount) and Debt Issuance Costs	11	11
Net, Long-term Debt	$ 445	445
Senior Notes [Member] | 4.875% Senior Notes Due 2023 (Existing Axiall 2023 Notes) [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,023
Stated interest rate (percent)	4.875%
Principal Amount	$ 16	16
Unamortized Premium (Discount) and Debt Issuance Costs	0	0
Net, Long-term Debt	$ 16	16
Senior Notes [Member] | 3.6% Senior Notes Due 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,026
Stated interest rate (percent)	3.60%
Principal Amount	$ 750	750
Unamortized Premium (Discount) and Debt Issuance Costs	(10)	(10)
Net, Long-term Debt	$ 740	740
Senior Notes [Member] | Loan related to tax-exempt waste disposal revenue bonds due 2027 [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,027
Principal Amount	$ 11	11
Unamortized Premium (Discount) and Debt Issuance Costs	0	0
Net, Long-term Debt	$ 11	11
Senior Notes [Member] | 6 1/2% Senior Notes Due 2029 [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,029
Stated interest rate (percent)	6.50%
Principal Amount	$ 100	100
Unamortized Premium (Discount) and Debt Issuance Costs	(1)	(1)
Net, Long-term Debt	$ 99	99
Senior Notes [Member] | 2035 GO Zone 6 1/2% Notes [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,035
Stated interest rate (percent)	6.50%
Principal Amount	$ 89	89
Unamortized Premium (Discount) and Debt Issuance Costs	(1)	(1)
Net, Long-term Debt	$ 88	88
Senior Notes [Member] | 2035 IKE Zone 6 1/2% Notes [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,035
Stated interest rate (percent)	6.50%
Principal Amount	$ 65	65
Unamortized Premium (Discount) and Debt Issuance Costs	0	0
Net, Long-term Debt	$ 65	65
Senior Notes [Member] | 5% Senior Notes Due 2046 [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,046
Stated interest rate (percent)	5.00%
Principal Amount	$ 700	700
Unamortized Premium (Discount) and Debt Issuance Costs	(25)	(25)
Net, Long-term Debt	$ 675	675
Senior Notes [Member] | 4.375% Senior Notes Due 2047 [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,047
Stated interest rate (percent)	4.375%
Principal Amount	$ 500	500
Unamortized Premium (Discount) and Debt Issuance Costs	(9)	(9)
Net, Long-term Debt	$ 491	491
Senior Notes [Member] | 3.50% Senior Notes Due 2032 [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,032
Stated interest rate (percent)	3.50%
Principal Amount	$ 250	250
Unamortized Premium (Discount) and Debt Issuance Costs	(2)	(2)
Net, Long-term Debt	$ 248	248
Senior Notes [Member] | 4.625% Senior Notes Due 2021 (New Westlake 2021 Notes) [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,021
Stated interest rate (percent)	4.625%
Principal Amount	$ 0	625
Unamortized Premium (Discount) and Debt Issuance Costs	0	20
Net, Long-term Debt	$ 0	645
Senior Notes [Member] | 4.625% Senior Notes Due 2021 (Existing Axiall 2021 Notes) [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity	2,021
Stated interest rate (percent)	4.625%
Principal Amount	$ 0	63
Unamortized Premium (Discount) and Debt Issuance Costs	0	2
Net, Long-term Debt	0	65
Senior Notes [Member] | 4.625% Senior Notes Due 2021 [Member]
Debt Instrument [Line Items]
Long-Term Debt, Gross, Current Maturities	0	688
Debt Instrument, Unamortized Premium (Discount) and debt issuance cost, net, Current Maturities	0	22
Long-term Debt, Current Maturities	0	710
Senior Notes [Member] | 4.875% Percent Senior Notes Due 2023 [Member]
Debt Instrument [Line Items]
Long-Term Debt, Gross, Current Maturities	450	0
Debt Instrument, Unamortized Premium (Discount) and debt issuance cost, net, Current Maturities	11	0
Long-term Debt, Current Maturities	$ 461	$ 0

Long-Term Debt (Credit Agreemen

Long-Term Debt (Credit Agreement) (Details) - Revolving Credit Facility [Member] $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)
Minimum [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.00%
Minimum [Member] | Alternate Base Rate [Domain]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.00%
Maximum [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.75%
Maximum [Member] | Alternate Base Rate [Domain]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.75%
Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,000
Line of Credit Facility, Fair Value of Amount Outstanding	0
Letters of Credit Outstanding, Amount	5
Line of Credit Facility, Remaining Borrowing Capacity	$ 995

Long-Term Debt (Senior Notes Du

Long-Term Debt (Senior Notes Due 2021) (Details) - 2021 Notes [Member] - USD ($) $ in Millions	Feb. 15, 2018	Mar. 31, 2018
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage	102.313%
Gain on debt redemption		$ 6

Long-Term Debt (Senior Notes 41

Long-Term Debt (Senior Notes Due 2023) (Details)	Mar. 15, 2018
2023 Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage	102.438%

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Unamortized Debt Issuance Cost	$ 26	$ 26

Derivative Instruments (Narrati

Derivative Instruments (Narrative) (Details) € in Millions	Jan. 31, 2018EUR (€)
Net Investment Hedging [Member] | Cross Currency Interest Rate Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount	€ 220

Derivative Instruments Derivati

Derivative Instruments Derivative Table (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Net Investment Hedging [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	$ (14)	$ 0
Net Investment Hedging [Member] | Other Income [Member]
Derivative [Line Items]
Gain (Loss) on Derivative Used in Net Investment Hedge, Net of Tax	1	$ 0
Designated as Hedging Instrument [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivative Liability	$ 18		$ 0

Fair Value Measurements (Summar

Fair Value Measurements (Summary of Carrying and Fair Values of Long Term Debt) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 3,127	$ 3,837
3.60% Senior Notes Due 2022 [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 249	249
Debt Instrument Maturity	2,022
Stated interest rate (percent)	3.60%
4.875% Senior Notes Due 2023 (New Westlake 2023 Notes) [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 445	445
Debt Instrument Maturity	2,023
Stated interest rate (percent)	4.875%
4.875% Senior Notes Due 2023 (Existing Axiall 2023 Notes) [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 16	16
Debt Instrument Maturity	2,023
Stated interest rate (percent)	4.875%
3.6% Senior Notes Due 2026 [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 740	740
Debt Instrument Maturity	2,026
Stated interest rate (percent)	3.60%
Loan related to tax-exempt waste disposal revenue bonds due 2027 [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 11	11
Debt Instrument Maturity	2,027
6 1/2% Senior Notes Due 2029 [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 99	99
Debt Instrument Maturity	2,029
Stated interest rate (percent)	6.50%
2035 GO Zone 6 1/2% Notes [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 88	88
Debt Instrument Maturity	2,035
Stated interest rate (percent)	6.50%
2035 IKE Zone 6 1/2% Notes [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 65	65
Debt Instrument Maturity	2,035
Stated interest rate (percent)	6.50%
5% Senior Notes Due 2046 [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 675	675
Debt Instrument Maturity	2,046
Stated interest rate (percent)	5.00%
4.375% Senior Notes Due 2047 [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 491	491
Debt Instrument Maturity	2,047
Stated interest rate (percent)	4.375%
3.50% Senior Notes Due 2032 [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 248	248
Debt Instrument Maturity	2,032
Stated interest rate (percent)	3.50%
4.625% Senior Notes Due 2021 (New Westlake 2021 Notes) [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 0	645
Debt Instrument Maturity	2,021
Stated interest rate (percent)	4.625%
4.625% Senior Notes Due 2021 (Existing Axiall 2021 Notes) [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 0	65
Debt Instrument Maturity	2,021
Stated interest rate (percent)	4.625%
Fair Value [Member] | 3.60% Senior Notes Due 2022 [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	$ 250	255
Fair Value [Member] | 4.875% Senior Notes Due 2023 (New Westlake 2023 Notes) [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	445	449
Fair Value [Member] | 4.875% Senior Notes Due 2023 (Existing Axiall 2023 Notes) [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	17	16
Fair Value [Member] | 3.6% Senior Notes Due 2026 [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	727	757
Fair Value [Member] | Loan related to tax-exempt waste disposal revenue bonds due 2027 [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	11	11
Fair Value [Member] | 6 1/2% Senior Notes Due 2029 [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	109	111
Fair Value [Member] | 2035 GO Zone 6 1/2% Notes [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	97	99
Fair Value [Member] | 2035 IKE Zone 6 1/2% Notes [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	71	74
Fair Value [Member] | 5% Senior Notes Due 2046 [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	740	787
Fair Value [Member] | 4.375% Senior Notes Due 2047 [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	484	518
Fair Value [Member] | 3.50% Senior Notes Due 2032 [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	246	256
Fair Value [Member] | 4.625% Senior Notes Due 2021 (New Westlake 2021 Notes) [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	0	639
Fair Value [Member] | 4.625% Senior Notes Due 2021 (Existing Axiall 2021 Notes) [Member] | Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	$ 0	$ 65

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective income tax rate	22.90%	27.90%
U.S. federal statutory income tax rate	21.00%	35.00%
Provisional adjustment of income tax benefit			$ 591

Earnings per Share (Schedule of

Earnings per Share (Schedule of Net Income Attributable to Common Stockholders) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Net income attributable to Westlake Chemical Corporation	$ 287	$ 138
Net income attributable to participating securities	(2)	(1)
Net income attributable to common shareholders	$ 285	$ 137

Earnings per Share (Reconciliat

Earnings per Share (Reconciliation of Denominator for Basic and Diluted Earnings Per Share) (Details) - $ / shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Weighted average common shares—basic	129,483,968	128,979,357
Incremental Shares From Assumed exercise of options	706,924	712,658
Weighted average common shares-diluted	130,190,892	129,692,015
Earnings per share attributable to Westlake Chemical Corporation: Basic	$ 2.21	$ 1.07
Earnings per share attributable to Westlake Chemical Corporation: Diluted	$ 2.20	$ 1.06

Earnings per Share (Additional

Earnings per Share (Additional Information) (Detail) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Number of options excluded from computation of diluted earnings per share	84,673	437,787

Supplemental Information ( Addi

Supplemental Information ( Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Accrued Liabilities [Abstract]
Accrued liabilities	$ 596		$ 657
Accrued Rebates, Current			108
Accrued Income Taxes			130
Due to Affiliate, Current	31		$ 37
Increase (Decrease) in Capital Expenditure Accrual	10	$ 8
Income from Unconsolidated Subsidiaries	9	$ 4
2021 Notes [Member]
Other Income [Line Items]
Gain on debt redemption	6
Cash and Cash Equivalents [Member]
Other Income [Line Items]
Interest Income, Other	$ 4

Commitments and Contingencies (

Commitments and Contingencies (Additional Information) (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	May 31, 2017	Mar. 31, 2018	Dec. 31, 2017
Environmental Loss Contingencies [Line Items]
Environmental Loss contingency accrual		$ 49	$ 49
Ownership interest (in percent)		100.00%
PolyOne [Member] | Pending Litigation [Member]
Environmental Loss Contingencies [Line Items]
Maximum Expected Damages	$ 17
Minimum [Member]
Environmental Loss Contingencies [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss		$ 55
Maximum [Member]
Environmental Loss Contingencies [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss		110
Environmental Protection Agency [Member] | Minimum [Member]
Environmental Loss Contingencies [Line Items]
Environmental Remediation Expense		200
Environmental Protection Agency [Member] | Maximum [Member]
Environmental Loss Contingencies [Line Items]
Environmental Remediation Expense		250
Environmental Protection Agency [Member] | Operation and Maintenance [Member] | Minimum [Member]
Environmental Loss Contingencies [Line Items]
Environmental Exit Costs, Anticipated Cost		1
Environmental Protection Agency [Member] | Operation and Maintenance [Member] | Maximum [Member]
Environmental Loss Contingencies [Line Items]
Environmental Exit Costs, Anticipated Cost		3
Affiliated Entity [Member] | LACC [Member]
Environmental Loss Contingencies [Line Items]
Maximum Capital Commitment		$ 225
Ownership interest (in percent)		10.00%
Funding to related parties		$ 141

Segment Information (Additional

Segment Information (Additional Information) (Detail)	3 Months Ended
	Mar. 31, 2018Segment
Segment Reporting [Abstract]
Number of segments	2

Segment Information (Segment Re

Segment Information (Segment Reporting Information) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Net sales	$ 2,150	$ 1,943
Income (loss) from operations	401	234
Depreciation and amortization	156	150
Other income (expense), net	22	7
Provision for (benefit from) income taxes	89	56
Additions to property, plant and equipment	(154)	(134)
Operating Segments [Member] | Olefins [Member]
Segment Reporting Information [Line Items]
Net sales	503	543
Income (loss) from operations	163	180
Depreciation and amortization	34	41
Other income (expense), net	2	1
Provision for (benefit from) income taxes	37	58
Additions to property, plant and equipment	(22)	(25)
Operating Segments [Member] | Vinyls [Member]
Segment Reporting Information [Line Items]
Net sales	1,647	1,400
Income (loss) from operations	266	70
Depreciation and amortization	118	107
Other income (expense), net	12	6
Provision for (benefit from) income taxes	61	15
Additions to property, plant and equipment	(130)	(108)
Operating Segments [Member] | Polyethylene [Member] | Olefins [Member]
Segment Reporting Information [Line Items]
Net sales	369	386
Operating Segments [Member] | Styrene, Feedstock And Other [Member] | Olefins [Member]
Segment Reporting Information [Line Items]
Net sales	134	157
Operating Segments [Member] | PVC, Caustic Soda And Other [Member] | Vinyls [Member]
Segment Reporting Information [Line Items]
Net sales	1,358	1,131
Operating Segments [Member] | Building Products [Member] | Vinyls [Member]
Segment Reporting Information [Line Items]
Net sales	289	269
Corporate and other [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations	(28)	(16)
Depreciation and amortization	4	2
Other income (expense), net	8	0
Provision for (benefit from) income taxes	(9)	(17)
Additions to property, plant and equipment	(2)	(1)
Intersegment sales [Member]
Segment Reporting Information [Line Items]
Net sales	120	86
Intersegment sales [Member] | Olefins [Member]
Segment Reporting Information [Line Items]
Net sales	120	86
Intersegment sales [Member] | Vinyls [Member]
Segment Reporting Information [Line Items]
Net sales	$ 0	$ 0

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
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting [Abstract]
Income from operations	$ 401	$ 234
Interest expense	(37)	(40)
Other income (expense), net	22	7
Income before income taxes	$ 386	$ 201

Segment Information (Total Asse

Segment Information (Total Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 11,604	$ 12,076
Operating Segments [Member] | Olefins [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,986	2,006
Operating Segments [Member] | Vinyls [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	9,081	8,853
Corporate and other [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 537	$ 1,217

Guarantor Disclosures (Addition

Guarantor Disclosures (Additional Information) (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)
Condensed Financial Statements, Captions [Line Items]
Ownership interest (in percent)	100.00%
3.60%, 5.0%, 4.625%, 4.875% Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Minimum debt amount guaranteed by subsidiaries	$ 5
4.375% Senior Notes Due 2047 [Member] | Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Stated interest rate (percent)	4.375%
Debt Instrument Maturity	2,047
3.60% Senior Notes Due 2022 [Member] | Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Stated interest rate (percent)	3.60%
Debt Instrument Maturity	2,022
3.6% Senior Notes Due 2026 [Member] | Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Stated interest rate (percent)	3.60%
Debt Instrument Maturity	2,026
5% Senior Notes Due 2046 [Member] | Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Stated interest rate (percent)	5.00%
Debt Instrument Maturity	2,046
4.875% Senior Notes Due 2023 (New Westlake 2023 Notes) [Member] | Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Stated interest rate (percent)	4.875%
Debt Instrument Maturity	2,023

Guarantor Disclosures (Condense

Guarantor Disclosures (Condensed Consolidating Financial Information Balance Sheets) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	$ 851	$ 1,531
Accounts receivable, net	1,135	1,001
Inventories	944	900
Prepaid expenses and other current assets	29	31
Total current assets	2,959	3,463
Property, plant and equipment, net	6,447	6,412
Goodwill	1,010	1,012
Customer relationships, net	594	616
Other intangible assets, net	160	161
Other assets, net	434	412
Total assets	11,604	12,076
Accounts payable	596	600
Accrued liabilities	596	657
Current portion of long-term debt	461	710
Total current liabilities	1,653	1,967
Long-term debt, net	2,666	3,127
Deferred income taxes	1,125	1,111
Pension and other liabilities	519	502
Total liabilities	5,963	6,707
Total Westlake Chemical Corporation stockholders' equity	5,141	4,874
Noncontrolling interests	500	495
Total equity	5,641	5,369	$ 4,033	$ 3,892
Total liabilities and equity	11,604	12,076
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	0	0
Accounts receivable, net	(8,225)	(7,038)
Inventories	0	0
Prepaid expenses and other current assets	(103)	(79)
Total current assets	(8,328)	(7,117)
Property, plant and equipment, net	0	0
Goodwill	0	0
Customer relationships, net	0	0
Other intangible assets, net	0	0
Other assets, net	(12,666)	(12,363)
Total assets	(20,994)	(19,480)
Accounts payable	(8,024)	(6,855)
Accrued liabilities	(303)	(262)
Current portion of long-term debt	0	0
Total current liabilities	(8,327)	(7,117)
Long-term debt, net	(4,396)	(4,369)
Deferred income taxes	(14)	(7)
Pension and other liabilities	0	0
Total liabilities	(12,737)	(11,493)
Total Westlake Chemical Corporation stockholders' equity	(8,257)	(7,987)
Noncontrolling interests	0	0
Total equity	(8,257)	(7,987)
Total liabilities and equity	(20,994)	(19,480)
Westlake Chemical Corporation [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	412	1,089
Accounts receivable, net	4,076	3,331
Inventories	0	0
Prepaid expenses and other current assets	88	52
Total current assets	4,576	4,472
Property, plant and equipment, net	0	0
Goodwill	0	0
Customer relationships, net	0	0
Other intangible assets, net	0	0
Other assets, net	11,003	10,706
Total assets	15,579	15,178
Accounts payable	7,142	6,367
Accrued liabilities	173	189
Current portion of long-term debt	445	710
Total current liabilities	7,760	7,266
Long-term debt, net	2,655	3,034
Deferred income taxes	0	0
Pension and other liabilities	23	4
Total liabilities	10,438	10,304
Total Westlake Chemical Corporation stockholders' equity	5,141	4,874
Noncontrolling interests	0	0
Total equity	5,141	4,874
Total liabilities and equity	15,579	15,178
100% Owned Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	59	57
Accounts receivable, net	4,651	4,128
Inventories	678	654
Prepaid expenses and other current assets	25	27
Total current assets	5,413	4,866
Property, plant and equipment, net	4,407	4,374
Goodwill	855	855
Customer relationships, net	463	479
Other intangible assets, net	87	88
Other assets, net	793	798
Total assets	12,018	11,460
Accounts payable	1,246	864
Accrued liabilities	488	484
Current portion of long-term debt	16	0
Total current liabilities	1,750	1,348
Long-term debt, net	4,183	4,242
Deferred income taxes	1,042	1,026
Pension and other liabilities	340	347
Total liabilities	7,315	6,963
Total Westlake Chemical Corporation stockholders' equity	4,703	4,497
Noncontrolling interests	0	0
Total equity	4,703	4,497
Total liabilities and equity	12,018	11,460
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	380	385
Accounts receivable, net	633	580
Inventories	266	246
Prepaid expenses and other current assets	19	31
Total current assets	1,298	1,242
Property, plant and equipment, net	2,040	2,038
Goodwill	155	157
Customer relationships, net	131	137
Other intangible assets, net	73	73
Other assets, net	1,304	1,271
Total assets	5,001	4,918
Accounts payable	232	224
Accrued liabilities	238	246
Current portion of long-term debt	0	0
Total current liabilities	470	470
Long-term debt, net	224	220
Deferred income taxes	97	92
Pension and other liabilities	156	151
Total liabilities	947	933
Total Westlake Chemical Corporation stockholders' equity	3,554	3,490
Noncontrolling interests	500	495
Total equity	4,054	3,985
Total liabilities and equity	$ 5,001	$ 4,918

Guarantor Disclosures (Conden58

Guarantor Disclosures (Condensed Consolidating Financial Information Statement of Operations) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 2,150	$ 1,943
Cost of sales	1,608	1,577
Gross profit	542	366
Selling, general and administrative expenses	108	99
Amortization of Intangible Assets	26	25
Transaction and integration-related costs	7	8
Income (loss) from operations	401	234
Interest expense	(37)	(40)
Other income (expense), net	22	7
Income before income taxes	386	201
Provision for (benefit from) income taxes	89	56
Equity in net income of subsidiaries	0	0
Net income	297	145
Net income attributable to noncontrolling interests	10	7
Net income attributable to Westlake Chemical Corporation	287	138
Comprehensive income attributable to Westlake Chemical Corporation	283	156
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	(435)	(373)
Cost of sales	(429)	(367)
Gross profit	(6)	(6)
Selling, general and administrative expenses	(6)	(6)
Amortization of Intangible Assets	0	0
Transaction and integration-related costs	0	0
Income (loss) from operations	0	0
Interest expense	44	45
Other income (expense), net	(44)	(45)
Income before income taxes	0	0
Provision for (benefit from) income taxes	0	0
Equity in net income of subsidiaries	(282)	(135)
Net income	(282)	(135)
Net income attributable to noncontrolling interests	0	0
Net income attributable to Westlake Chemical Corporation	(282)	(135)
Comprehensive income attributable to Westlake Chemical Corporation	(280)	(127)
Westlake Chemical Corporation [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	0	0
Cost of sales	0	0
Gross profit	0	0
Selling, general and administrative expenses	0	1
Amortization of Intangible Assets	0	0
Transaction and integration-related costs	0	0
Income (loss) from operations	0	(1)
Interest expense	(38)	(38)
Other income (expense), net	45	37
Income before income taxes	7	(2)
Provision for (benefit from) income taxes	2	(5)
Equity in net income of subsidiaries	282	135
Net income	287	138
Net income attributable to noncontrolling interests	0	0
Net income attributable to Westlake Chemical Corporation	287	138
Comprehensive income attributable to Westlake Chemical Corporation	283	156
100% Owned Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	1,746	1,580
Cost of sales	1,405	1,362
Gross profit	341	218
Selling, general and administrative expenses	77	73
Amortization of Intangible Assets	19	19
Transaction and integration-related costs	7	8
Income (loss) from operations	238	118
Interest expense	(32)	(46)
Other income (expense), net	(8)	3
Income before income taxes	198	75
Provision for (benefit from) income taxes	63	53
Equity in net income of subsidiaries	0	0
Net income	135	22
Net income attributable to noncontrolling interests	0	0
Net income attributable to Westlake Chemical Corporation	135	22
Comprehensive income attributable to Westlake Chemical Corporation	135	5
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	839	736
Cost of sales	632	582
Gross profit	207	154
Selling, general and administrative expenses	37	31
Amortization of Intangible Assets	7	6
Transaction and integration-related costs	0	0
Income (loss) from operations	163	117
Interest expense	(11)	(1)
Other income (expense), net	29	12
Income before income taxes	181	128
Provision for (benefit from) income taxes	24	8
Equity in net income of subsidiaries	0	0
Net income	157	120
Net income attributable to noncontrolling interests	10	7
Net income attributable to Westlake Chemical Corporation	147	113
Comprehensive income attributable to Westlake Chemical Corporation	$ 145	$ 122

Guarantor Disclosures (Conden59

Guarantor Disclosures (Condensed Consolidating Financial Information Statement of Cash Flows) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 874	$ 405	$ 1,554	$ 646
Net income	297	145
Depreciation and amortization	156	150
Deferred income taxes	16	(6)
Net changes in working capital and other	(244)	(132)
Net cash provided by operating activities	225	157
Additions to property, plant and equipment	(154)	(134)
Payments to Acquire Additional Interest in Subsidiaries	(26)	(15)
Other	2	1
Net cash used for investing activities	(178)	(148)
Intercompany financing	0	0
Dividends paid	(27)	(24)
Distributions to noncontrolling interests	(7)	(4)
Proceeds from debt issuance and drawdown of revolver	4	52
Repayment of term loan	0	(150)
Repayment of revolver	0	(125)
Repayment of notes payable	(706)	(2)
Other	5	0
Net cash used for financing activities	(731)	(253)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	4	3
Net decrease in cash, cash equivalents and restricted cash	(680)	(241)
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	0	0	0	0
Net income	(282)	(135)
Depreciation and amortization	0	0
Deferred income taxes	0	0
Net changes in working capital and other	282	135
Net cash provided by operating activities	0	0
Additions to property, plant and equipment	0	0
Payments to Acquire Additional Interest in Subsidiaries	0	0
Other	0	0
Net cash used for investing activities	0	0
Intercompany financing	0	0
Dividends paid	0	0
Distributions to noncontrolling interests	0	0
Proceeds from debt issuance and drawdown of revolver	0	0
Repayment of term loan		0
Repayment of revolver		0
Repayment of notes payable	0	0
Other	0
Net cash used for financing activities	0	0
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0	0
Net decrease in cash, cash equivalents and restricted cash	0	0
Westlake Chemical Corporation [Member]
Condensed Financial Statements, Captions [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	412	51	1,089	147
Net income	287	138
Depreciation and amortization	0	0
Deferred income taxes	0	0
Net changes in working capital and other	(220)	(213)
Net cash provided by operating activities	67	(75)
Additions to property, plant and equipment	0	0
Payments to Acquire Additional Interest in Subsidiaries	0	0
Other	0	0
Net cash used for investing activities	0	0
Intercompany financing	(18)	78
Dividends paid	(27)	(24)
Distributions to noncontrolling interests	0	0
Proceeds from debt issuance and drawdown of revolver	0	50
Repayment of term loan		0
Repayment of revolver		(125)
Repayment of notes payable	(704)	0
Other	5
Net cash used for financing activities	(744)	(21)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0	0
Net decrease in cash, cash equivalents and restricted cash	(677)	(96)
100% Owned Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	81	30	79	78
Net income	135	22
Depreciation and amortization	103	98
Deferred income taxes	12	(3)
Net changes in working capital and other	(211)	(29)
Net cash provided by operating activities	39	88
Additions to property, plant and equipment	(122)	(121)
Payments to Acquire Additional Interest in Subsidiaries	(16)	(15)
Other	2	1
Net cash used for investing activities	(136)	(135)
Intercompany financing	2	(96)
Dividends paid	0	0
Distributions to noncontrolling interests	97	95
Proceeds from debt issuance and drawdown of revolver	0	0
Repayment of term loan		0
Repayment of revolver		0
Repayment of notes payable	0	0
Other	0
Net cash used for financing activities	99	(1)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0	0
Net decrease in cash, cash equivalents and restricted cash	2	(48)
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	381	324	$ 386	$ 421
Net income	157	120
Depreciation and amortization	53	52
Deferred income taxes	4	(3)
Net changes in working capital and other	(95)	(25)
Net cash provided by operating activities	119	144
Additions to property, plant and equipment	(32)	(13)
Payments to Acquire Additional Interest in Subsidiaries	(10)	0
Other	0	0
Net cash used for investing activities	(42)	(13)
Intercompany financing	16	18
Dividends paid	0	0
Distributions to noncontrolling interests	(104)	(99)
Proceeds from debt issuance and drawdown of revolver	4	2
Repayment of term loan		(150)
Repayment of revolver		0
Repayment of notes payable	(2)	(2)
Other	0
Net cash used for financing activities	(86)	(231)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	4	3
Net decrease in cash, cash equivalents and restricted cash	$ (5)	$ (97)

Accumulated Other Comprehensi60

Accumulated Other Comprehensive Income (Loss) (Schedule of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 5,641	$ 4,033	$ 5,369	$ 3,892
Accumulated other comprehensive income	3	(104)	7	(121)
Other comprehensive income (loss)	(2)	20
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	43	29	43	29
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0
Other comprehensive income (loss)	0	0
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(40)	(133)	(36)	(150)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(4)	17
Other comprehensive income (loss)	(4)	17
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	3	(104)	$ 7	$ (121)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(4)	17
Other comprehensive income (loss)	$ (4)	$ 17