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Fair value measurements, investments and notes receivable - Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Measured on a Recurring Basis - USD ($) $ in Millions | Mar. 31, 2024 | Dec. 31, 2023
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Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash and cash equivalents | $ 8,401 | $ 6,058
Restricted cash — current | 40 | 31
Restricted cash — non-current | 244 | 245
Equity securities | 116 | 177
U.S. government and agency notes |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 5,518 | 8,257
Certificates of deposit placed through an account registry service ("CDARS") |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 73 | 73
Level 1 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash and cash equivalents | 8,401 | 6,058
Restricted cash — current | 40 | 31
Restricted cash — non-current | 244 | 245
Equity securities | 116 | 177
Level 1 | U.S. government and agency notes |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 0 | 0
Level 1 | Certificates of deposit placed through an account registry service ("CDARS") |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 0 | 0
Level 2 |  |
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
Level 2 | U.S. government and agency notes |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 5,518 | 8,257
Level 2 | Certificates of deposit placed through an account registry service ("CDARS") |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 73 | 73
Level 3 |  |
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
Level 3 | U.S. government and agency notes |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 0 | 0
Level 3 | Certificates of deposit placed through an account registry service ("CDARS") |  |
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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