INVESTMENTS - Schedule of Financial Instruments by Significant Categories and Fair Value Measurement on a Recurring Basis (Details) - Fair Value Measurements on a Recurring Basis - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Financial Instruments [Line Items]
Total cash equivalents	$ 190	$ 332
Amortized Cost	457	464
Gross Unrealized Gains	2	0
Gross Unrealized Losses	(3)	(4)
Fair Value	456	460
Cash and Cash Equivalents
Fair Value, Financial Instruments [Line Items]
Total cash equivalents	101	243
Fair Value	0	0
Investments
Fair Value, Financial Instruments [Line Items]
Total cash equivalents	0	0
Fair Value	208	226
Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Total cash equivalents	89	89
Fair Value	248	234
Asset-backed securities | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	41	42
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1)	(2)
Fair Value	40	40
Asset-backed securities | Level 2 | Cash and Cash Equivalents
Fair Value, Financial Instruments [Line Items]
Fair Value	0	0
Asset-backed securities | Level 2 | Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	40	40
Asset-backed securities | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	0	0
Corporate bonds | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	135	140
Gross Unrealized Gains	1	0
Gross Unrealized Losses	0	(1)
Fair Value	136	139
Corporate bonds | Level 2 | Cash and Cash Equivalents
Fair Value, Financial Instruments [Line Items]
Fair Value	0	0
Corporate bonds | Level 2 | Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	103	112
Corporate bonds | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	33	27
Agency securities | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	40	33
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1)	(1)
Fair Value	39	32
Agency securities | Level 2 | Cash and Cash Equivalents
Fair Value, Financial Instruments [Line Items]
Fair Value	0	0
Agency securities | Level 2 | Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	10	5
Agency securities | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	29	27
U.S. treasuries | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	231	229
Gross Unrealized Gains	1	0
Gross Unrealized Losses	(1)	0
Fair Value	231	229
U.S. treasuries | Level 2 | Cash and Cash Equivalents
Fair Value, Financial Instruments [Line Items]
Fair Value	0	0
U.S. treasuries | Level 2 | Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	47	62
U.S. treasuries | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	184	167
Certificate of deposit | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	2	12
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	2	12
Certificate of deposit | Level 2 | Cash and Cash Equivalents
Fair Value, Financial Instruments [Line Items]
Fair Value	0	0
Certificate of deposit | Level 2 | Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	0	0
Certificate of deposit | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	2	12
Other debt securities | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	8	8
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	8	8
Other debt securities | Level 2 | Cash and Cash Equivalents
Fair Value, Financial Instruments [Line Items]
Fair Value	0	0
Other debt securities | Level 2 | Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	8	7
Other debt securities | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	0	1
Money market mutual funds | Level 1
Fair Value, Financial Instruments [Line Items]
Total cash equivalents	183	314
Money market mutual funds | Level 1 | Cash and Cash Equivalents
Fair Value, Financial Instruments [Line Items]
Total cash equivalents	96	225
Money market mutual funds | Level 1 | Investments
Fair Value, Financial Instruments [Line Items]
Total cash equivalents	0	0
Money market mutual funds | Level 1 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Total cash equivalents	87	89
U.S. treasuries | Level 2
Fair Value, Financial Instruments [Line Items]
Total cash equivalents	7	18
U.S. treasuries | Level 2 | Cash and Cash Equivalents
Fair Value, Financial Instruments [Line Items]
Total cash equivalents	5	18
U.S. treasuries | Level 2 | Investments
Fair Value, Financial Instruments [Line Items]
Total cash equivalents	0	0
U.S. treasuries | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Total cash equivalents	$ 2	$ 0