STOCK-BASED COMPENSATION - Additional Information on RSUs (Details) - RSUs - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Restricted Stock Activity [Line Items]
Stock-based compensation expense (in millions)	$ 188	$ 177	$ 170
Weighted average grant-date fair value (in USD per share)	$ 101	$ 117	$ 132
Aggregate intrinsic value of distributed RSUs (in millions)	$ 234	$ 276	$ 294

Share Based Compensation Arrangement by Share Based Payment Award, Equity Instruments Other Than Options, Converted and Distributed, Intrinsic Value

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- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

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).

+ References

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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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