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Related Party And Affiliate Transactions (Details) $ in Millions, T in Billions		4 Months Ended	12 Months Ended
	Jun. 17, 2015 USD ($) T	Dec. 31, 2016 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Related Party Transaction [Line Items]
Ownership interest (in percent)			100.00%
Related party receivable		$ 8	$ 9	$ 8
Dividends received from equity method investments			6	5	$ 6
Affiliates [Member]
Related Party Transaction [Line Items]
Incurred and paid lease payments			3	3	2
Pipeline Fees For Transport Of Natural Gas Liquid Feedstocks [Member] \| Cypress Interstate Pipeline L.L.C [Member] \| Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Purchases from related parties			15	14	14
Accounts payable due to affiliate		1	$ 1	1
Cypress Interstate Pipeline L.L.C [Member] \| Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Ownership interest (in percent)			50.00%
Investments in joint ventures		9	$ 9	9
EPS Ethylene Pipeline Süd GmbH & Co. KG [Member] \| Affiliates [Member]
Related Party Transaction [Line Items]
Ownership percentage by parent			10.00%
EPS Ethylene Pipeline Süd GmbH & Co. KG [Member] \| Pipeline Fees For Transport Of Ethylene Feedstocks [Member] \| Affiliates [Member]
Related Party Transaction [Line Items]
Purchases from related parties			$ 0	1	1
Accounts payable due to affiliate		0	$ 0	0
InfraServ Knapsack GmbH & Co. KG [Member] \| Affiliates [Member]
Related Party Transaction [Line Items]
Ownership percentage by parent			15.00%
InfraServ Gendorf GmbH & Co. KG [Member] \| Affiliates [Member]
Related Party Transaction [Line Items]
Ownership percentage by parent			11.00%
InfraServ Knapsack & Gendorf GmbH & Co. KG [Member] \| Affiliates [Member]
Related Party Transaction [Line Items]
Investments in joint ventures		50	$ 56	50
InfraServ Knapsack & Gendorf GmbH & Co. KG [Member] \| Electricity And Technical Services [Member] \| Affiliates [Member]
Related Party Transaction [Line Items]
Purchases from related parties			133	131	116
Accounts payable due to affiliate		25	$ 33	25
Shriram Axiall Private Limited [Member] \| Affiliates [Member]
Related Party Transaction [Line Items]
Ownership interest (in percent)			50.00%
Investments in joint ventures		2	$ 0	2
RS Cogen LLC [Member] \| Affiliates [Member]
Related Party Transaction [Line Items]
Investments in joint ventures		10	10	10
Purchases from related parties		9	26
Accounts payable due to affiliate		1	$ 2	1
RS Cogen LLC [Member] \| Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Ownership interest (in percent)			50.00%
Vinyl Solutions, LLC [Member] \| Affiliates [Member]
Related Party Transaction [Line Items]
Ownership interest (in percent)			50.00%
Sales to related parties		6	$ 17
Related party receivable		5	7	5
LACC [Member] \| Affiliates [Member]
Related Party Transaction [Line Items]
Ownership interest (in percent)	10.00%
Investments in joint ventures		59	125	59
Related party receivable		1	0	1
Plant capacity (in T) \| T	1
Maximum Capital Commitment	$ 225
Optional ownership percentage	50.00%
Funding to related parties		17	66
American Air Liquide Holdings [Member] \| American Air Liquide Holdings, Inc. [Member]
Related Party Transaction [Line Items]
Sales to related parties			7	4
Related party receivable		1	1	1
Accounts payable due to related parties		$ 4	2	4
Purchases and lease expense to related parties			$ 30	$ 22	$ 10