Income Taxes - Narrative (Details) $ in Millions |
12 Months Ended | |||
|---|---|---|---|---|
|
Dec. 31, 2017
USD ($)
|
Dec. 31, 2019
USD ($)
|
Dec. 31, 2018
USD ($)
|
Dec. 31, 2017 |
|
| Income Tax Disclosure [Abstract] | ||||
| Provisional tax expense estimate as a result of enactment of Tax Cuts and Jobs Act of 2017 | $ 395 | |||
| Tax benefit after finalizing impact of the Tax Cuts and Jobs Act of 2017 | $ 26 | |||
| Change in effective tax rate due to Tax Cuts and Jobs Act of 2017 (percent) | 0.072 | 0 | (0.005) | 0.072 |
| Basis difference in investments in foreign subsidiaries considered to be indefinitely reinvested | $ 212 | |||
| Federal alternative minimum tax credit carryforwards | 94 | $ 189 | ||
| Operating loss carryforwards | 1,900 | |||
| Deferred income taxes, pension obligation | $ 672 | |||