v3.19.3.a.u2
Fair Value Measurement (Details) - USD ($)
$ in Millions
Dec. 31, 2019
Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Marketable securities $ 35,776 $ 31,095
Total cash equivalents and marketable securities 50,120 38,401
Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Total cash equivalents and marketable securities 39,437 29,105
Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Total cash equivalents and marketable securities 10,683 9,296
Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Total cash equivalents and marketable securities 0 0
Money market funds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 12,787 6,792
Money market funds | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 12,787 6,792
Money market funds | Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 0 0
Money market funds | Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 0 0
U.S. government securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 815 90
U.S. government securities | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 815 90
U.S. government securities | Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 0 0
U.S. government securities | Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 0 0
U.S. government agency securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 444 54
U.S. government agency securities | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 444 54
U.S. government agency securities | Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 0 0
U.S. government agency securities | Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 0 0
Certificate of deposits and time deposits    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 217 369
Certificate of deposits and time deposits | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 0 0
Certificate of deposits and time deposits | Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 217 369
Certificate of deposits and time deposits | Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 0 0
Corporate debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 81 1
Corporate debt securities | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 0 0
Corporate debt securities | Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 81 1
Corporate debt securities | Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash equivalents 0 0
U.S. government securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Marketable securities 18,679 13,836
U.S. government securities | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Marketable securities 18,679 13,836
U.S. government securities | Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Marketable securities 0 0
U.S. government securities | Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Marketable securities 0 0
U.S. government agency securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Marketable securities 6,712 8,333
U.S. government agency securities | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Marketable securities 6,712 8,333
U.S. government agency securities | Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Marketable securities 0 0
U.S. government agency securities | Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Marketable securities 0 0
Corporate debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Marketable securities 10,385 8,926
Corporate debt securities | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Marketable securities 0 0
Corporate debt securities | Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Marketable securities 10,385 8,926
Corporate debt securities | Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Marketable securities $ 0 $ 0