INVESTMENTS - Carrying Value of Non-marketable Equity Securities Measured Using the Measurement Alternative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Equity Securities without Readily Determinable Fair Value, Annual Amount [Abstract]
Measurement alternative—carrying value	$ 741,000,000		$ 700,000,000
Measurement alternative—impairment losses	3,000,000	$ 5,000,000
Measurement alternative—downward changes for observable prices	0	0
Measurement alternative—upward changes for observable prices	25,000,000	66,000,000
Equity Securities without Readily Determinable Fair Value, Impairment Loss, Cumulative Amount [Abstract]
Measurement alternative—impairment losses	19,000,000
Measurement alternative—downward changes for observable prices	34,000,000
Measurement alternative—upward changes for observable prices	367,000,000
Non-marketable equity securities, impairment loss recognized in earnings	$ 0	$ 0