Supplemental Balance Sheet and Cash Flow Information - Inventory Components (Details) - USD ($) $ in Millions |
Mar. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Text Block [Abstract] | ||
| Raw materials | $ 490 | $ 442 |
| Work in process and finished goods | 600 | 580 |
| Inventory reserves | (58) | (53) |
| Total | $ 1,032 | $ 969 |