Retirement-Related Benefits - Contributions (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2021 |
Dec. 31, 2020 |
|
| Retirement-Related Benefits | ||
| Contributions by employer - Noncash | $ 424 | $ 288 |
| Nonpension Postretirement Plans | Non-U.S. DB plans | ||
| Retirement-Related Benefits | ||
| Contributions by employer - Noncash | 416 | $ 452 |
| Non-U.S. | Pension Plans, Including Multi-employer Plans | ||
| Retirement-Related Benefits | ||
| Estimated cash contributions to the defined benefit plans in next fiscal year | $ 200 | |