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Financial Instruments and Fair Value Measurements - Summary 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, 2022 | Dec. 31, 2021
--- | --- | ---
Fair Value, Financial Instruments [Line Items] |  |
Cash equivalents: | $ 270 | $ 119
Amortized Cost | 521 | 538
Gross Unrealized Gains | 0 | 2
Gross Unrealized Losses | (16) | (2)
Fair Value | 505 | 538
Cash and cash equivalents |  |
Fair Value, Financial Instruments [Line Items] |  |
Cash equivalents: | 181 | 25
Fair Value | 0 | 0
Investments |  |
Fair Value, Financial Instruments [Line Items] |  |
Cash equivalents: | 0 | 0
Fair Value | 279 | 303
Restricted Cash, Cash Equivalents and Investments |  |
Fair Value, Financial Instruments [Line Items] |  |
Cash equivalents: | 89 | 94
Fair Value | 226 | 235
Money market mutual funds | Level 1 |  |
Fair Value, Financial Instruments [Line Items] |  |
Cash equivalents: | 228 | 97
Money market mutual funds | Level 1 | Cash and cash equivalents |  |
Fair Value, Financial Instruments [Line Items] |  |
Cash equivalents: | 139 | 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: | 42 | 22
U.S. treasuries | Level 2 | Cash and cash equivalents |  |
Fair Value, Financial Instruments [Line Items] |  |
Cash equivalents: | 42 | 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
Asset-backed securities | Level 2 |  |
Fair Value, Financial Instruments [Line Items] |  |
Amortized Cost | 46 | 49
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (2) | 0
Fair Value | 44 | 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 | 44 | 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 | 163 | 167
Gross Unrealized Gains | 0 | 1
Gross Unrealized Losses | (5) | (1)
Fair Value | 158 | 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 | 128 | 137
Corporate bonds | Level 2 | Restricted Cash, Cash Equivalents and Investments |  |
Fair Value, Financial Instruments [Line Items] |  |
Fair Value | 30 | 30
Agency securities | Level 2 |  |
Fair Value, Financial Instruments [Line Items] |  |
Amortized Cost | 23 | 17
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (1) | 0
Fair Value | 22 | 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 | 4 | 2
Agency securities | Level 2 | Restricted Cash, Cash Equivalents and Investments |  |
Fair Value, Financial Instruments [Line Items] |  |
Fair Value | 18 | 15
U.S. treasuries | Level 2 |  |
Fair Value, Financial Instruments [Line Items] |  |
Amortized Cost | 271 | 285
Gross Unrealized Gains | 0 | 1
Gross Unrealized Losses | (8) | (1)
Fair Value | 263 | 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 | 94 | 106
U.S. treasuries | Level 2 | Restricted Cash, Cash Equivalents and Investments |  |
Fair Value, Financial Instruments [Line Items] |  |
Fair Value | 169 | 179
Certificate of deposits | Level 2 |  |
Fair Value, Financial Instruments [Line Items] |  |
Amortized Cost | 9 | 11
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | 0 | 0
Fair Value | 9 | 11
Certificate of deposits | Level 2 | Cash and cash equivalents |  |
Fair Value, Financial Instruments [Line Items] |  |
Fair Value | 0 | 0
Certificate of deposits | Level 2 | Investments |  |
Fair Value, Financial Instruments [Line Items] |  |
Fair Value |  | 0
Certificate of deposits | Level 2 | Restricted Cash, Cash Equivalents and Investments |  |
Fair Value, Financial Instruments [Line Items] |  |
Fair Value | 9 | 11
Other debt securities | Level 2 |  |
Fair Value, Financial Instruments [Line Items] |  |
Amortized Cost | 9 | 9
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | 0 | 0
Fair Value | 9 | 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 | 9 | 9
Other debt securities | Level 2 | Restricted Cash, Cash Equivalents and Investments |  |
Fair Value, Financial Instruments [Line Items] |  |
Fair Value | $ 0 | $ 0

X
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