INCOME TAXES - Reconciliation Schedule of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance, beginning of year	$ 654	$ 598	$ 423
Additions based on tax positions related to the current year	361	18	145
Additions for tax positions of prior years	63	55	57
Reductions for tax positions of prior years	(58)	(11)	(18)
Lapse of statute of limitations	(18)	(6)	(9)
Balance, end of year	$ 1,002	$ 654	$ 598