STOCKHOLDERS' EQUITY AND STOCK-BASED COMPENSATION STOCKHOLDERS' EQUITY AND STOCK-BASED COMPENSATION (Cash-settled RSUs and PSUs) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Accounts payable and accrued liabilities	$ 2,576	$ 2,625
Cash Settled Restricted Stock Units (RSUs) and Performance Share Units (PSU's) [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)	1,486,866
Granted in period (number of RSUs and PSUs)	819,000
Vested in Period (number of RSUs and PSUs)	(698,817)
Forfeited in Period (number of RSUs and PSUs)	(24,162)
Balance at end of period (in number of RSUs and PSUs)	1,582,887	1,486,866
Beginning Balance - weighted average grant date fair value	$ 15.61
Granted - Weighted average grant date fair value	11.88
Vested - weighted average grant date fair value	13.70
Forfeited - weighted average grant date fair value	14.43
Ending balance - weighted average grant date fair value	$ 14.54	$ 15.61
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding	$ 21
Fair value of RSUs and PSUs granted	10	$ 16	$ 10
Intrinsic value of RSUs and PSUs vested	8	11	$ 24
Other Liabilities	3	3
Accounts payable and accrued liabilities	$ 11	$ 7
Cash Settled Restricted Stock Units (RSUs) and Performance Share Units (PSU's) [Member] \| Minimum
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

Fair value of RSUs and PSUs granted.

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Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, taxes, interest, rent and utilities, accrued salaries and bonuses, payroll taxes and fringe benefits.

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Amount of liabilities classified as other.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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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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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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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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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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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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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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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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Intrinsic value of outstanding award under share-based payment arrangement. Excludes share and unit options.

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Intrinsic value of vested award under share-based payment arrangement. Excludes share and unit options.

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