Supplemental Balance Sheet Information - PP&E (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Property, plant and equipment - at cost | ||
| Gross property, plant and equipment | $ 24,914 | $ 23,499 |
| Less: Accumulated depreciation | (16,048) | (14,983) |
| Property, Plant and Equipment - net | 8,866 | 8,516 |
| Accumulated depreciation for capital leases included in Accumulated depreciation | 48 | 89 |
| Land | ||
| Property, plant and equipment - at cost | ||
| Gross property, plant and equipment | 348 | 341 |
| Buildings and leasehold improvements | ||
| Property, plant and equipment - at cost | ||
| Gross property, plant and equipment | 7,681 | 7,252 |
| Machinery and equipment | ||
| Property, plant and equipment - at cost | ||
| Gross property, plant and equipment | 15,907 | 14,935 |
| Construction in progress | ||
| Property, plant and equipment - at cost | ||
| Gross property, plant and equipment | 843 | 809 |
| Capital leases | ||
| Property, plant and equipment - at cost | ||
| Gross property, plant and equipment | $ 135 | $ 162 |