Pension and Postretirement Benefit Plans - Pension Asset Fair Value Level 3 (Details) - Qualified and Non-qualified Pension Benefits - International - Funded - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Benefit Plan Information | ||
| Foreign currency exchange | $ (80) | $ 346 |
| Level 3 | ||
| Benefit Plan Information | ||
| Defined benefit plan increases related to net purchases and unrealized gains losses | $ 17 | |
| Defined benefit plan decreases related to net purchases and unrealized gains losses | $ 11 | |