Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

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Costs incurred to effect a business combination which have been expensed during the period. Such costs could include business integration costs, systems integration and conversion costs, and severance and other employee-related costs.

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Unrecognized cost of unvested share-based compensation awards.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of tax benefit from exercise of stock options granted under share-based compensation arrangement.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period, Fair Value

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Stock-Based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Aug. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense on restricted stock	$ 18	$ 14	$ 14
Transaction and integration-related costs	33	29	104
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	21	24	4
Employee Service Share-based Compensation, Tax Benefit from Exercise of Stock Options	$ 4	8	1
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option awards, term (in years)	10 years
Unrecognized compensation expense	$ 5
Unrecognized compensation expense, weighted-average period of recognition (in years)	1 year 8 months 12 days
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 17
Unrecognized compensation expense, weighted-average period of recognition (in years)	1 year 6 months
Total fair value of shares of restricted stock that vested	$ 10	6	4
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	0
Total fair value of shares of restricted stock that vested	$ 0	0	4
Cliff Vest [Member] \| Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, vesting period	5 years
Cliff Vest [Member] \| Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, vesting period	6 years
Ratably On Annual Basis [Member] \| Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, vesting period	3 years
Ratably On Annual Basis [Member] \| Restricted Stock Units (RSUs) [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, vesting period	2 years
Ratably On Annual Basis [Member] \| Restricted Stock Units (RSUs) [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, vesting period	5 years
Axiall Corporation [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share price (in dollars per share)				$ 33.00
Axiall Corporation [Member] \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense on restricted stock	$ 4	9	38
Transaction and integration-related costs			33
Unrecognized compensation expense	$ 1
Unrecognized compensation expense, weighted-average period of recognition (in years)	3 months
Total fair value of shares of restricted stock that vested	$ 6	$ 11	$ 3
Total fair value of shares of restricted stock that were cancelled	$ 0