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Interest Cost Components (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2017
Debt Disclosure [Abstract] |
Schedule of Interest Cost Components |
| 2017 | 2016 | 2015
Amount charged to expense | $ | 496 |  | $ | 499 |  | $ | 473 |
Amount capitalized | 22 |  | 32 |  | 27 |
| $ | 518 |  | $ | 531 |  | $ | 500 |

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