Taxes - Unrecognized Tax Benefits Additional Disclosures (Details) - USD ($) $ in Millions |
12 Months Ended | |||
|---|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Taxes | ||||
| Unrecognized tax benefits | $ 8,568 | $ 7,146 | $ 6,759 | $ 7,031 |
| Offsetting tax benefits associated with timing adjustments, U.S. tax credits, potential transfer pricing adjustments, and state income taxes | 574 | |||
| Net unrecognized tax benefit amount that, if recognized, would favorably affect the company's effective tax rate | 7,994 | 6,562 | 6,041 | |
| Interest expense and penalties, net (benefit)/charge recognized | 117 | 13 | $ (14) | |
| Interest and penalties accrued | 843 | $ 819 | ||
| Reasonably possible reduction in unrecognized tax benefits within the next 12 months | $ 368 | |||