STOCK INCENTIVE PLANS - Components of Restricted Stock Units (Details) $ in Millions	9 Months Ended
Sep. 30, 2021 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested restricted stock units (in shares) \| shares	4,561,091
Unrecognized compensation expense	$ 12
Intrinsic value	$ 53
Weighted average remaining life (in years)	1 year 6 months 3 days
Service-Based Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested restricted stock units (in shares) \| shares	2,933,219
Unrecognized compensation expense	$ 10
Intrinsic value	$ 34
Weighted average remaining life (in years)	1 year 10 months 9 days
Performance-based Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested restricted stock units (in shares) \| shares	1,627,872
Unrecognized compensation expense	$ 2
Intrinsic value	$ 19
Weighted average remaining life (in years)	10 months 17 days

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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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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Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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 by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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