Inventories (Detail) - USD ($) $ in Millions |
Dec. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Inventory Disclosure [Abstract] | ||
| Raw materials | $ 4,182 | $ 3,479 |
| Work in process and other | 2,625 | 2,568 |
| Finished manufactured goods | 4,541 | 4,505 |
| Goods acquired for resale | 7,721 | 6,814 |
| Total inventory | $ 19,069 | $ 17,366 |