Income Taxes (Summary of Activity Related to Gross 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] | |||
| Beginning Balance | $ 3,837 | $ 3,377 | $ 4,652 |
| Increases related to prior year tax positions | 529 | 372 | 938 |
| Decreases related to prior year tax positions | (263) | (557) | (143) |
| Decreases related to settlement with tax authorities | (329) | (45) | (2,886) |
| Increases related to current year tax positions | 1,384 | 690 | 816 |
| Ending Balance | $ 5,158 | $ 3,837 | $ 3,377 |