Stockholders' Equity - Stock-Based Compensation Expense (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2021 |
Jun. 30, 2020 |
Jun. 30, 2021 |
Jun. 30, 2020 |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Share-based compensation expense | $ 272 | $ 131 | $ 553 | $ 408 |
| Operations and support | ||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Share-based compensation expense | 38 | 11 | 65 | 36 |
| Sales and marketing | ||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Share-based compensation expense | 19 | 10 | 42 | 24 |
| Research and development | ||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Share-based compensation expense | 149 | 72 | 282 | 239 |
| General and administrative | ||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Share-based compensation expense | $ 66 | $ 38 | $ 164 | $ 109 |