Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2023 |
Dec. 31, 2022 |
Dec. 31, 2021 |
|
| Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] | |||
| Unrecognized tax benefits, beginning of year | $ 1,254 | $ 1,217 | $ 1,159 |
| Gross increases to tax positions in prior periods | 19 | 31 | 73 |
| Gross decreases to tax positions in prior periods | (39) | (65) | (123) |
| Gross increases to current period tax positions | 256 | 77 | 72 |
| Gross increases due to current period business acquisitions | 0 | 0 | 36 |
| Gross decreases due to settlements with taxing authorities | 0 | (3) | 0 |
| Gross decreases due to statute of limitations lapse | (13) | (3) | 0 |
| Unrecognized tax benefits, end of year | $ 1,477 | $ 1,254 | $ 1,217 |