Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities
Net income	$ 181	$ 211
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	381	347
Stock-based compensation expense	14	13
Loss from disposition and write-off of property, plant and equipment	9	27
Deferred income taxes	96	15
Other losses, net	3	16
Changes in operating assets and liabilities, net of effect of business acquisitions
Accounts receivable	(128)	(119)
Inventories	87	125
Prepaid expenses and other current assets	(16)	(8)
Accounts payable	8	(40)
Accrued and other liabilities	(75)	(62)
Other, net	(51)	(58)
Net cash provided by operating activities	509	467
Cash flows from investing activities
Acquisition of businesses, net of cash acquired	0	(314)
Additions to property, plant and equipment	(291)	(411)
Additions to investments in unconsolidated subsidiaries	0	(42)
Return of investment from an equity investee	39	0
Other, net	(8)	4
Net cash used for investing activities	(260)	(763)
Cash flows from financing activities
Dividends paid	(68)	(65)
Distributions to noncontrolling interests	(29)	(30)
Net proceeds from issuance of Westlake Chemical Partners LP common units	0	63
Net proceeds from debt issuance and drawdown of revolver	1,299	0
Proceeds from (repayment of) short-term notes payable	(14)	4
Repayment of revolver	(1,000)	0
Repurchase of common stock for treasury	(54)	(20)
Other	(3)	0
Net cash provided by (used for) financing activities	131	(48)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0	0
Net increase (decrease) in cash, cash equivalents and restricted cash	380	(344)
Cash, cash equivalents and restricted cash at beginning of period	750	775
Cash, cash equivalents and restricted cash at end of period	$ 1,130	$ 431