v3.19.3
Investments and Fair Value Measurement - Fair Value of Unobservable Inputs, Liabilities (Details)
$ in Millions
9 Months Ended
Sep. 30, 2019
USD ($)
Warrants  
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]  
Balance as of December 31, 2018 $ 52
Vesting of share warrants 1
Exercise of vested share warrants (53)
Change in fair value 0
Settlement of derivative liability 0
Balance as of September 30, 2019 0
Convertible Debt Embedded Derivative  
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]  
Balance as of December 31, 2018 2,018
Vesting of share warrants 0
Exercise of vested share warrants 0
Change in fair value (58)
Settlement of derivative liability (1,960)
Balance as of September 30, 2019 $ 0