Post-Employment Benefits - Pretax Gains and Losses Included in Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Defined benefit plans | |||
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | |||
| Actuarial loss | $ 1,231 | $ 209 | $ 412 |
| Amortization of actuarial loss and prior service credit | (109) | (140) | (107) |
| Foreign exchange loss (gain) and other | (6) | (13) | 46 |
| Total loss (gain) | 1,116 | 56 | 351 |
| Other post-employment plans | |||
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | |||
| Actuarial loss | 451 | (287) | 149 |
| Amortization of actuarial loss and prior service credit | (1) | (1) | |
| Total loss (gain) | $ 450 | $ (288) | $ 149 |