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Financial Instruments and Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Millions | Jun. 30, 2021 | Dec. 31, 2020
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Clear Secure, Inc. |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Equity securities | $ 31 |
Measured on a Recurring Basis |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash and cash equivalents | 20,838 | $ 11,269
Restricted cash - current | 254 | 255
Restricted cash - non-current | 216 | 218
Equity securities | 269 | 205
Warrants | 176 | 36
Level 1 | Measured on a Recurring Basis |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash and cash equivalents | 20,838 | 11,269
Restricted cash - current | 254 | 255
Restricted cash - non-current | 216 | 218
Equity securities | 269 | 205
Warrants | 96 | 0
Level 2 | Measured on a Recurring Basis |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash and cash equivalents | 0 | 0
Restricted cash - current | 0 | 0
Restricted cash - non-current | 0 | 0
Equity securities | 0 | 0
Warrants | 80 | 0
Level 3 | Measured on a Recurring Basis |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash and cash equivalents | 0 | 0
Restricted cash - current | 0 | 0
Restricted cash - non-current | 0 | 0
Equity securities | 0 | 0
Warrants | 0 | 36
Corporate debt | Measured on a Recurring Basis |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments | 199 | 330
Corporate debt | Level 1 | Measured on a Recurring Basis |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments | 0 | 0
Corporate debt | Level 2 | Measured on a Recurring Basis |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments | 199 | 330
Corporate debt | Level 3 | Measured on a Recurring Basis |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments | 0 | 0
Asset-backed securities | Measured on a Recurring Basis |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments | 23 | 51
Asset-backed securities | Level 1 | Measured on a Recurring Basis |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments | 0 | 0
Asset-backed securities | Level 2 | Measured on a Recurring Basis |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments | 23 | 51
Asset-backed securities | Level 3 | Measured on a Recurring Basis |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments | 0 | 0
U.S. government and agency notes | Measured on a Recurring Basis |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments | 8 | 33
U.S. government and agency notes | Level 1 | Measured on a Recurring Basis |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments | 0 | 0
U.S. government and agency notes | Level 2 | Measured on a Recurring Basis |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments | 8 | 33
U.S. government and agency notes | Level 3 | Measured on a Recurring Basis |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments | $ 0 | $ 0

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- Definition Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. + References No definition available. + Details
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