Acquisitions (Purchase Price Allocation) (Details) - USD ($) $ in Millions		12 Months Ended
	Aug. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill		$ 1,012	$ 947	$ 62
Goodwill, Purchase Accounting Adjustments		$ 55
Customer relationships [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	9 years 9 months 18 days
Trade Name [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	6 years 9 months 18 days
Technology [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	5 years 4 months 24 days
Supply Contracts and Leases [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	6 years 3 months 18 days
Axiall Corporation [Member]
Business Acquisition [Line Items]
Cash	$ 88
Accounts Receivable	422
Income tax receivable	51
Inventories	349
Prepaid expenses and other current assets	56
Property, plant and equipment	2,942
Other assets	94
Total assets acquired	4,791
Accounts and notes payable	254
Interest payable	8
Income tax payable	2
Accrued compensation	44
Accrued liabilities	154
Deferred income taxes	958
Tax reserve non-current	3
Pension and other post retirement obligations	311
Other liabilities	102
Long-term debt	1,187
Total liabilities assumed	3,023
Total identifiable net assets acquired	1,768
Noncontrolling interest	(68)
Goodwill	942
Total fair value allocated to net assets acquired	2,642
Business Combination, Acquired Receivables, Gross Contractual Amount	435
Business Combination, Acquired Receivables, Estimated Uncollectible	13
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Inventory	43
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment	(193)
Goodwill, Purchase Accounting Adjustments	150
Axiall Corporation [Member] | Customer relationships [Member]
Business Acquisition [Line Items]
Finite-lived intangibles	670
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles	80
Axiall Corporation [Member] | Trade Name [Member]
Business Acquisition [Line Items]
Finite-lived intangibles	50
Axiall Corporation [Member] | Technology [Member]
Business Acquisition [Line Items]
Finite-lived intangibles	42
Axiall Corporation [Member] | Supply Contracts and Leases [Member]
Business Acquisition [Line Items]
Finite-lived intangibles	27
Deferred Income Tax [Member]
Business Acquisition [Line Items]
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments Related to Previous Period	$ (27)