Increase or decrease in performance stock units if performance is above or below level defined in agreement.

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- Definition

Fair value of RSUs and PSUs granted.

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No definition available.

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Performance share unit payout based upon certain performance metrics.

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- Definition

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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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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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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- Definition

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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- Definition

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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No definition available.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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No definition available.

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Intrinsic value of equity-based compensation awards outstanding. Excludes stock and unit options.

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No definition available.

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- Definition

Intrinsic value of equity-based compensation awards vested. Excludes stock and unit options.

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No definition available.

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STOCKHOLDERS' EQUITY AND STOCK-BASED COMPENSATION STOCKHOLDERS' EQUITY AND STOCK-BASED COMPENSATION (Equity RSUs and PSUs) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent Addition or Reduction In Restricted Stock Units If Performance Is Below Level Defined In Agreement	25.00%	25.00%
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Granted in period (number of RSUs and PSUs)	500,000	600,000	1,500,000
Performance Shares [Member] \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Performance Share Unit Payout	200.00%	175.00%
Performance Shares [Member] \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance Share Unit Payout	0.00%	0.00%
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Restricted Stock Units (RSUs) and Performance Share Units (PSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Balance at beginning of period (in number of RSUs and PSUs)	5,206,624
Granted in period (number of RSUs and PSUs)	2,127,785
Vested in Period (number of RSUs and PSUs)	(753,806)
Forfeited in Period (number of RSUs and PSUs)	(775,966)
Balance at end of period (in number of RSUs and PSUs)	5,804,637	5,206,624
Beginning Balance - weighted average grant date fair value	$ 18.48
Granted - Weighted average grant date fair value	19.11
Vested - weighted average grant date fair value	15.53
Forfeited - weighted average grant date fair value	11.91
Ending balance - weighted average grant date fair value	$ 19.97	$ 18.48
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding	$ 60
Fair value of RSUs and PSUs granted	41	$ 32	$ 37
Intrinsic value of RSUs and PSUs vested	14	$ 45	$ 22	$ 22
Total unrecognized compensation cost related to unvested RSUs and PSUs expected to be recognized over a weighted-average period	$ 6
Weighted-average period used in calculating unrecognized compensation cost, RSUs and PSUs (in years)	1 year 1 month
Outside Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		1 year
Outside Directors [Member] \| Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	4 years
2017 [Member] \| Share-based Compensation Award, Tranche Three [Member] \| Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Granted in period (number of RSUs and PSUs)	187,000