Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
|
| Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] | |||
| Unrecognized tax benefits, beginning of year | $ 1,159 | $ 514 | $ 462 |
| Gross increases to tax positions in prior periods | 73 | 6 | 0 |
| Gross decreases to tax positions in prior periods | (123) | (28) | 0 |
| Gross increases to current period tax positions | 72 | 45 | 64 |
| Gross increases due to current period business acquisitions | 36 | 624 | 0 |
| Gross decreases due to settlements with taxing authorities | 0 | (2) | (12) |
| Unrecognized tax benefits, end of year | $ 1,217 | $ 1,159 | $ 514 |