Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities
Net income	$ 903	$ 523
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	473	449
Stock-based compensation expense	16	17
Loss from disposition of property, plant and equipment	26	14
Deferred income taxes	74	23
Other gains, net	(20)	(3)
Changes in operating assets and liabilities
Accounts receivable	(252)	(185)
Inventories	(42)	24
Prepaid expenses and other current assets	(3)	17
Accounts payable	36	61
Accrued liabilities	9	57
Other, net	(65)	(35)
Net cash provided by operating activities	1,155	962
Cash flows from investing activities
Additions to property, plant and equipment	(507)	(414)
Additions to investments in unconsolidated subsidiaries	(63)	(47)
Other, net	9	1
Net cash used for investing activities	(561)	(460)
Cash flows from financing activities
Dividends paid	(87)	(76)
Distributions to noncontrolling interests	(37)	(21)
Proceeds from notes payable and drawdown of revolver	11	231
Net proceeds from issuance of Westlake Chemical Partners LP common units	0	111
Repayment of term loan	0	(150)
Repayment of revolver	0	(550)
Redemption and repayment of notes payable	(1,177)	(7)
Repurchase of common stock for treasury	(49)
Other	8	2
Net cash used for financing activities	(1,331)	(460)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(6)	22
Net increase (decrease) in cash, cash equivalents and restricted cash	(743)	64
Cash, cash equivalents and restricted cash at beginning of period	1,554	646
Cash, cash equivalents and restricted cash at end of period	$ 811	$ 710