Acquisitions (Narrative) (Details) $ / shares in Units, shares in Thousands, lb in Millions, $ in Millions				4 Months Ended	12 Months Ended
	Aug. 31, 2016 USD ($) $ / shares	Aug. 30, 2016 shares	Jun. 01, 2015 USD ($) lb	Dec. 31, 2016 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	May 31, 2015
Business Acquisition [Line Items]
Transaction and integration-related costs					$ 29	$ 104	$ 0
Goodwill				$ 947	$ 1,012	947	62
Ownership Percentage held prior to acquisition					100.00%
Axiall Corporation [Member]
Business Acquisition [Line Items]
Equity interest in acquiree held prior to combination, shares | shares		3,100
Offer price per share (usd per share) | $ / shares	$ 33.00
Purchase price	$ 2,540
Professional fees				49		49
Share-based awards, Retention & Severance						55
Contribution to net sales				976
Contribution to net loss				$ 96
Goodwill	$ 942
Remeasurement gain (loss)						$ 49
Suzhou Huasu Plastics Company Ltd [Member]
Business Acquisition [Line Items]
Remeasurement gain (loss)							$ (2)
Fair value of consideration transferred-cash			$ 6
Bargain purchase gain on acquisition			$ 23
Suzhou Huasu Plastics Company Ltd [Member] | PVC Resin [Member]
Business Acquisition [Line Items]
Combined annual capacity (in lb's) | lb			300
Suzhou Huasu Plastics Company Ltd [Member] | PVC Film [Member]
Business Acquisition [Line Items]
Combined annual capacity (in lb's) | lb			145
Suzhou Huasu Plastics Company Ltd [Member] | Affiliates [Member]
Business Acquisition [Line Items]
Percentage of interests acquired			35.70%
Percentage of interest held after acquisition			95.00%
Ownership Percentage held prior to acquisition								59.30%