Consolidated Statements Of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities
Net income	$ 462	$ 1,034	$ 1,339
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	713	641	601
Stock-based compensation expense	25	22	23
Loss from disposition and write-off of property, plant and equipment	49	44	22
Deferred income taxes	54	62	(534)
Other losses (gains), net	1	(20)	(3)
Changes in operating assets and liabilities, net of effect of business acquisitions
Accounts receivable	59	(58)	(40)
Inventories	112	(123)	(32)
Prepaid expenses and other current assets	(1)	(1)	26
Accounts payable	(89)	(100)	86
Accrued and other liabilities	(13)	(8)	115
Other, net	(71)	(84)	(75)
Net cash provided by operating activities	1,301	1,409	1,528
Cash flows from investing activities
Acquisition of businesses, net of cash acquired	(314)	0	(13)
Additions to property, plant and equipment	(787)	(702)	(577)
Additions to investments in unconsolidated subsidiaries	(862)	(68)	(66)
Other, net	9	16	4
Net cash used for investing activities	(1,954)	(754)	(652)
Cash flows from financing activities
Dividends paid	(132)	(120)	(103)
Distributions to noncontrolling interests	(50)	(45)	(28)
Proceeds from Issuance of Debt	784	0	0
Proceeds from notes payable	20	14	978
Net proceeds from issuance of Westlake Chemical Partners LP common units	63	0	111
Repayment of term loan	0	0	(150)
Repayment of revolver	0	0	(550)
Redemption and repayment of notes payable	(18)	(1,179)	(257)
Repurchase of common stock for treasury	(30)	(106)	0
Other	(7)	9	5
Net cash provided by (used for) financing activities	630	(1,427)	6
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(2)	(7)	26
Net increase (decrease) in cash, cash equivalents and restricted cash	(25)	(779)	908
Cash, cash equivalents and restricted cash at beginning of the year	775	1,554	646
Cash, cash equivalents and restricted cash at end of the year	$ 750	$ 775	$ 1,554