Fair Value Measurements and Disclosures - Assets Measured on Recurring Basis or Disclosed at Fair Value (Details) - Recurring Fair Value Measurements [Member] - USD ($) $ in Millions | Mar. 31, 2021 | Dec. 31, 2020 |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | | | |
Cash equivalents, Fair Value Measurement or Disclosure | | $ 480 | $ 808 |
Short-term investments, Fair Value Measurement or Disclosure | | 3,026 | 3,105 |
Total assets, Fair Value Measurement or Disclosure | | 3,974 | 4,134 |
Level 1 [Member] | | | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | | | |
Cash equivalents, Fair Value Measurement or Disclosure | | | 207 |
Short-term investments, Fair Value Measurement or Disclosure | | | 260 |
Total assets, Fair Value Measurement or Disclosure | | 405 | 627 |
Level 2 [Member] | | | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | | | |
Cash equivalents, Fair Value Measurement or Disclosure | | 480 | 601 |
Short-term investments, Fair Value Measurement or Disclosure | | 3,026 | 2,845 |
Total assets, Fair Value Measurement or Disclosure | | 3,569 | 3,507 |
Time Deposits [Member] | | | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | | | |
Cash equivalents, Fair Value Measurement or Disclosure | | 410 | 601 |
Short-term investments, Fair Value Measurement or Disclosure | | 2,058 | 2,165 |
Other assets, Fair Value Measurement or Disclosure | | | 61 |
Time Deposits [Member] | Level 2 [Member] | | | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | | | |
Cash equivalents, Fair Value Measurement or Disclosure | | 410 | 601 |
Short-term investments, Fair Value Measurement or Disclosure | | 2,058 | 2,165 |
Other assets, Fair Value Measurement or Disclosure | | | 61 |
Fixed Income Debt Securities [Member] | | | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | | | |
Cash equivalents, Fair Value Measurement or Disclosure | [1] | 70 | 207 |
Short-term investments, Fair Value Measurement or Disclosure | [1] | 800 | 784 |
Fixed Income Debt Securities [Member] | Level 1 [Member] | | | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | | | |
Cash equivalents, Fair Value Measurement or Disclosure | [1] | | 207 |
Short-term investments, Fair Value Measurement or Disclosure | [1] | | 104 |
Fixed Income Debt Securities [Member] | Level 2 [Member] | | | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | | | |
Cash equivalents, Fair Value Measurement or Disclosure | [1] | 70 | |
Short-term investments, Fair Value Measurement or Disclosure | [1] | 800 | 680 |
Structured Deposits [Member] | | | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | | | |
Short-term investments, Fair Value Measurement or Disclosure | [2] | 168 | |
Structured Deposits [Member] | Level 2 [Member] | | | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | | | |
Short-term investments, Fair Value Measurement or Disclosure | [2] | 168 | |
Variable Return Investments [Member] | | | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | | | |
Short-term investments, Fair Value Measurement or Disclosure | | | 156 |
Variable Return Investments [Member] | Level 1 [Member] | | | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | | | |
Short-term investments, Fair Value Measurement or Disclosure | | | 156 |
Investment in Equity Securities [Member] | | | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | | | |
Other assets, Fair Value Measurement or Disclosure | | 405 | 160 |
Investment in Equity Securities [Member] | Level 1 [Member] | | | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | | | |
Other assets, Fair Value Measurement or Disclosure | | 405 | $ 160 |
Long-term Time Deposits [Member] | | | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | | | |
Other assets, Fair Value Measurement or Disclosure | | 63 | |
Long-term Time Deposits [Member] | Level 2 [Member] | | | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | | | |
Other assets, Fair Value Measurement or Disclosure | | $ 63 | |
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[1] | Classified as held-to-maturity investments and measured at amortized cost. | |
[2] | Represented certain structured deposits invested in the first quarter of 2021. These investments are principal-protected and provide returns in the form of both fixed and variable interests. Such variable interest rates indexed to gold prices or foreign exchange rates are considered embedded derivatives and bifurcated from host contracts, and measured at fair value on a recurring basis. | |