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INVESTMENTS - Summary 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, 2022	Dec. 31, 2021
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	$ 332	$ 119
Amortized Cost	464	538
Gross Unrealized Gains	0	2
Gross Unrealized Losses	(4)	(2)
Fair Value	460	538
Cash and Cash Equivalents
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	243	25
Fair Value	0	0
Investments
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	0	0
Fair Value	226	303
Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	89	94
Fair Value	234	235
Asset-backed securities | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	42	49
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(2)	0
Fair Value	40	49
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	49
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	140	167
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(1)	(1)
Fair Value	139	167
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	112	137
Corporate bonds | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	27	30
Agency securities | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	33	17
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1)	0
Fair Value	32	17
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	5	2
Agency securities | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	27	15
U.S. treasuries | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	229	285
Gross Unrealized Gains	0	1
Gross Unrealized Losses	0	(1)
Fair Value	229	285
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	62	106
U.S. treasuries | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	167	179
Certificate of deposit | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	12	11
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	12	11
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	12	11
Other debt securities | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	8	9
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	8	9
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	7	9
Other debt securities | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	1	0
Money market mutual funds | Level 1
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	314	97
Money market mutual funds | Level 1 | Cash and Cash Equivalents
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	225	4
Money market mutual funds | Level 1 | Investments
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	0	0
Money market mutual funds | Level 1 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	89	93
U.S. treasuries | Level 2
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	18	22
U.S. treasuries | Level 2 | Cash and Cash Equivalents
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	18	21
U.S. treasuries | Level 2 | Investments
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	0	0
U.S. treasuries | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	$ 0	$ 1

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- Definition

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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