v3.19.3.a.u2
Investments and Fair Value Measurement - Fair Value of Unobservable Inputs, Liabilities (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Warrants    
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Beginning balance $ 52 $ 125
Vesting of share warrants 1 41
Exercise of vested share warrants (53) (2)
Change in fair value 0 (120)
Settlement of derivative liability 0 8
Ending balance 0 52
Convertible Debt Embedded Derivative    
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Beginning balance 2,018 1,517
Vesting of share warrants 0 0
Exercise of vested share warrants 0 0
Change in fair value (58) 0
Settlement of derivative liability (1,960) 501
Ending balance $ 0 $ 2,018