INVESTMENTS - Schedule of Financial Instruments by Significant Categories and Fair Value Measurement on a Recurring Basis (Details) - Fair Value Measurement on a Recurring Basis - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Debt Securities
Cash equivalents:	$ 189	$ 332
Amortized Cost	462	464
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(7)	(4)
Fair Value	455	460
Cash and Cash Equivalents
Debt Securities
Cash equivalents:	103	243
Fair Value	0	0
Investments
Debt Securities
Cash equivalents:	0	0
Fair Value	215	226
Restricted Cash, Cash Equivalents and Investments
Debt Securities
Cash equivalents:	86	89
Fair Value	240	234
Asset-backed securities | Level 2
Debt Securities
Amortized Cost	47	42
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(2)	(2)
Fair Value	45	40
Asset-backed securities | Level 2 | Cash and Cash Equivalents
Debt Securities
Fair Value	0	0
Asset-backed securities | Level 2 | Investments
Debt Securities
Fair Value	45	40
Asset-backed securities | Level 2 | Restricted Cash, Cash Equivalents and Investments
Debt Securities
Fair Value	0	0
Corporate bonds | Level 2
Debt Securities
Amortized Cost	122	140
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1)	(1)
Fair Value	121	139
Corporate bonds | Level 2 | Cash and Cash Equivalents
Debt Securities
Fair Value	0	0
Corporate bonds | Level 2 | Investments
Debt Securities
Fair Value	96	112
Corporate bonds | Level 2 | Restricted Cash, Cash Equivalents and Investments
Debt Securities
Fair Value	25	27
Agency securities | Level 2
Debt Securities
Amortized Cost	36	33
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1)	(1)
Fair Value	35	32
Agency securities | Level 2 | Cash and Cash Equivalents
Debt Securities
Fair Value	0	0
Agency securities | Level 2 | Investments
Debt Securities
Fair Value	6	5
Agency securities | Level 2 | Restricted Cash, Cash Equivalents and Investments
Debt Securities
Fair Value	29	27
U.S. treasuries | Level 2
Debt Securities
Amortized Cost	245	229
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(3)	0
Fair Value	242	229
U.S. treasuries | Level 2 | Cash and Cash Equivalents
Debt Securities
Fair Value	0	0
U.S. treasuries | Level 2 | Investments
Debt Securities
Fair Value	62	62
U.S. treasuries | Level 2 | Restricted Cash, Cash Equivalents and Investments
Debt Securities
Fair Value	180	167
Certificate of deposit | Level 2
Debt Securities
Amortized Cost	6	12
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	6	12
Certificate of deposit | Level 2 | Cash and Cash Equivalents
Debt Securities
Fair Value	0	0
Certificate of deposit | Level 2 | Investments
Debt Securities
Fair Value	0	0
Certificate of deposit | Level 2 | Restricted Cash, Cash Equivalents and Investments
Debt Securities
Fair Value	6	12
Other debt securities | Level 2
Debt Securities
Amortized Cost	6	8
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	6	8
Other debt securities | Level 2 | Cash and Cash Equivalents
Debt Securities
Fair Value	0	0
Other debt securities | Level 2 | Investments
Debt Securities
Fair Value	6	7
Other debt securities | Level 2 | Restricted Cash, Cash Equivalents and Investments
Debt Securities
Fair Value	0	1
Money market mutual funds | Level 1
Debt Securities
Cash equivalents:	163	314
Money market mutual funds | Level 1 | Cash and Cash Equivalents
Debt Securities
Cash equivalents:	77	225
Money market mutual funds | Level 1 | Investments
Debt Securities
Cash equivalents:	0	0
Money market mutual funds | Level 1 | Restricted Cash, Cash Equivalents and Investments
Debt Securities
Cash equivalents:	86	89
U.S. treasuries | Level 2
Debt Securities
Cash equivalents:	26	18
U.S. treasuries | Level 2 | Cash and Cash Equivalents
Debt Securities
Cash equivalents:	26	18
U.S. treasuries | Level 2 | Investments
Debt Securities
Cash equivalents:	0	0
U.S. treasuries | Level 2 | Restricted Cash, Cash Equivalents and Investments
Debt Securities
Cash equivalents:	$ 0	$ 0