Segment Reporting and Information about Geographic Areas - Schedule of Long-Lived Assets by Geographic Area (Detail) - USD ($) $ in Millions |
Dec. 31, 2020 |
Dec. 31, 2019 |
|---|---|---|
| Revenues from External Customers and Long-Lived Assets [Line Items] | ||
| Long-lived Assets | $ 18,726 | $ 16,534 |
| United States [Member] | ||
| Revenues from External Customers and Long-Lived Assets [Line Items] | ||
| Long-lived Assets | 15,989 | 15,644 |
| International [Member] | ||
| Revenues from External Customers and Long-Lived Assets [Line Items] | ||
| Long-lived Assets | $ 2,737 | $ 890 |