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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, 2024	Dec. 31, 2023
Debt Securities
Cash equivalents:	$ 135	$ 190
Amortized Cost	471	457
Gross Unrealized Gains	0	2
Gross Unrealized Losses	(4)	(3)
Fair Value	467	456
Cash and Cash Equivalents
Debt Securities
Cash equivalents:	38	101
Fair Value	0	0
Investments
Debt Securities
Cash equivalents:	0	0
Fair Value	228	208
Restricted Cash, Cash Equivalents and Investments
Debt Securities
Cash equivalents:	97	89
Fair Value	239	248
Asset-backed securities | Level 2
Debt Securities
Amortized Cost	43	41
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	(1)
Fair Value	43	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	43	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	137	135
Gross Unrealized Gains	0	1
Gross Unrealized Losses	0	0
Fair Value	137	136
Corporate bonds | Level 2 | Cash and Cash Equivalents
Debt Securities
Fair Value	0	0
Corporate bonds | Level 2 | Investments
Debt Securities
Fair Value	103	103
Corporate bonds | Level 2 | Restricted Cash, Cash Equivalents and Investments
Debt Securities
Fair Value	34	33
Agency securities | Level 2
Debt Securities
Amortized Cost	34	40
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1)	(1)
Fair Value	33	39
Agency securities | Level 2 | Cash and Cash Equivalents
Debt Securities
Fair Value	0	0
Agency securities | Level 2 | Investments
Debt Securities
Fair Value	7	10
Agency securities | Level 2 | Restricted Cash, Cash Equivalents and Investments
Debt Securities
Fair Value	26	29
U.S. treasuries | Level 2
Debt Securities
Amortized Cost	249	231
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(3)	(1)
Fair Value	246	231
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	68	47
U.S. treasuries | Level 2 | Restricted Cash, Cash Equivalents and Investments
Debt Securities
Fair Value	178	184
Certificate of deposit | Level 2
Debt Securities
Amortized Cost	1	2
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	1	2
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	1	2
Other debt securities | Level 2
Debt Securities
Amortized Cost	7	8
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	7	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	7	8
Other debt securities | Level 2 | Restricted Cash, Cash Equivalents and Investments
Debt Securities
Fair Value	0	0
Money market mutual funds | Level 1
Debt Securities
Cash equivalents:	128	183
Money market mutual funds | Level 1 | Cash and Cash Equivalents
Debt Securities
Cash equivalents:	38	96
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:	90	87
U.S. treasuries | Level 2
Debt Securities
Cash equivalents:	7	7
U.S. treasuries | Level 2 | Cash and Cash Equivalents
Debt Securities
Cash equivalents:	0	5
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:	$ 7	$ 2

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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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