Property, Plant And Equipment And Asset Retirement Obligations (Property, Plant And Equipment) (Details) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|---|
| Property, Plant and Equipment [Line Items] | |||
| Property, plant and equipment, cost | $ 486,702 | $ 477,190 | |
| Property, plant and equipment, net | 253,018 | 247,101 | $ 252,630 |
| Upstream [Member] | |||
| Property, Plant and Equipment [Line Items] | |||
| Property, plant and equipment, cost | 376,041 | 372,791 | |
| Property, plant and equipment, net | 196,767 | 194,662 | |
| Downstream [Member] | |||
| Property, Plant and Equipment [Line Items] | |||
| Property, plant and equipment, cost | 52,527 | 48,241 | |
| Property, plant and equipment, net | 24,506 | 21,448 | |
| Chemical [Member] | |||
| Property, Plant and Equipment [Line Items] | |||
| Property, plant and equipment, cost | 40,788 | 39,008 | |
| Property, plant and equipment, net | 21,260 | 20,551 | |
| Other [Member] | |||
| Property, Plant and Equipment [Line Items] | |||
| Property, plant and equipment, cost | 17,346 | 17,150 | |
| Property, plant and equipment, net | $ 10,485 | $ 10,440 |