Employee Benefit Plans - Change in Benefit Obligations (Details) (Parenthetical) - Pension Plans Defined Benefit [Member] - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| U.S. | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Accumulated benefit obligation | $ 2,161 | $ 1,969 |
| Foreign Plan [Member] | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Accumulated benefit obligation | $ 3,594 | $ 3,066 |