Quarterly Financial Information (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Summary Of Quarterly Financial Information

	Three Months Ended
	March 31, 2017		June 30, 2017		September 30, 2017		December 31, 2017
Net sales	$	1,943	$	1,979	$	2,109	$	2,010
Gross profit	368		405		498		498
Income from operations	236		266		366		365
Net income	145		159		219		816
Net income attributable to    Westlake Chemical Corporation	138		153		211		802
Earnings per common share attributable to Westlake Chemical Corporation: (1)
Basic	$	1.07	$	1.18	$	1.62	$	6.18
Diluted	$	1.06	$	1.17	$	1.61	$	6.15
	Three Months Ended
	March 31, 2016		June 30, 2016		September 30, 2016		December 31, 2016
Net sales	$	975	$	1,086	$	1,280	$	1,735
Gross profit	255		241		203		282
Income from operations	202		180		46		153
Net income	129		116		70		105
Net income attributable to    Westlake Chemical Corporation	123		111		66		99
Earnings per common share attributable to Westlake Chemical Corporation: (1)
Basic	$	0.94	$	0.85	$	0.51	$	0.76
Diluted	$	0.94	$	0.85	$	0.51	$	0.76

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(1) Basic and diluted earnings per common share ("EPS") for each quarter is computed using the weighted average shares outstanding during that quarter, while EPS for the year is computed using the weighted average shares outstanding for the year. As a result, the sum of the EPS for each of the four quarters may not equal the EPS for the year.