FAIR VALUE MEASUREMENTS - Summary of Classification of Equity Securities (Details) - Other Equity Securities - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total	$ 5,494	$ 6,970
Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Marketable equity securities	3,383	4,361
Prepaid and other current assets
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Marketable equity securities	319	853
Other long-term assets
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Marketable equity securities	$ 1,792	$ 1,756