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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

X
- 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). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-2 + Details
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- Definition Amount, before tax, of unrealized loss 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). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-2 + Details
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