Segment And Geographic Information (Segment Reporting Information) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Segment Reporting Information [Line Items]
Net external sales	$ 951,625	$ 1,004,165	$ 939,047	$ 864,647	$ 801,041	$ 821,175	$ 913,958	$ 1,034,867	$ 3,759,484	[1]	$ 3,571,041	[1]	$ 3,619,848	[1]
Intersegment sales									322,411		319,925		446,363
Income (loss) from operations	257,580	266,602	235,227	194,055	156,231	142,517	170,978	145,625	953,464		615,351		446,796
Depreciation and amortization									157,808		144,541		131,397
Other income, net									6,790		3,520		5,628
Provision for income taxes									331,747		199,614		142,466
Property, Plant and Equipment, Additions									679,222		386,882		176,843
Olefins [Member]
Segment Reporting Information [Line Items]
Net external sales									2,553,669		2,499,978		2,567,842
Intersegment sales									320,909		318,322		444,889
Income (loss) from operations									833,249		552,762		459,266
Depreciation and amortization									102,938		97,906		86,915
Other income, net									7,410		3,899		2,813
Provision for income taxes									288,214		177,176		149,033
Property, Plant and Equipment, Additions									145,542		135,886		90,641
Vinyls [Member]
Segment Reporting Information [Line Items]
Net external sales									1,205,815		1,071,063		1,052,006
Intersegment sales									1,502		1,603		1,474
Income (loss) from operations									154,684		85,942		4,012
Depreciation and amortization									54,371		46,146		43,877
Other income, net									(1,858)		(965)		194
Provision for income taxes									48,296		22,389		(2,193)
Property, Plant and Equipment, Additions									531,939		246,827		84,192
Corporate And Other [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations									(34,469)		(23,353)		(16,482)
Depreciation and amortization									499		489		605
Other income, net									1,238		586		2,621
Provision for income taxes									(4,763)		49		(4,374)
Property, Plant and Equipment, Additions									1,741		4,169		2,010
Polyethylene [Member] | Olefins [Member]
Segment Reporting Information [Line Items]
Net external sales									1,750,292		1,658,551		1,772,144
Ethylene, Styrene And Other [Member] | Olefins [Member]
Segment Reporting Information [Line Items]
Net external sales									803,377		841,427		795,698
Building Products [Member] | Vinyls [Member]
Segment Reporting Information [Line Items]
Net external sales									405,157		327,788		294,692
PVC, Caustic Soda And Other [Member] | Vinyls [Member]
Segment Reporting Information [Line Items]
Net external sales									$ 800,658		$ 743,275		$ 757,314

[1] Revenues are attributed to countries based on location of customer.