The following tables present information about our assets and liabilities that are measured at fair value on a recurring basis at March 31, 2018 and December 31, 2017. The following tables also indicate the fair value hierarchy of the valuation techniques we utilized to determine such fair values. In general, fair values determined by Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities. We consider a security that trades at least weekly to have an active market. Fair values determined by Level 2 inputs utilize data points that are observable, such as quoted prices for similar assets, interest rates and yield curves. Fair values determined by Level 3 inputs are unobservable data points for the asset or liability, and include situations where there is little, if any, market activity for the asset or liability. | | | | | | | | | | | | | | | | | | Investments | | March 31, 2018 | | Quoted Prices in Active Markets for Identical Assets (Level 1) | | Significant Other Observable Inputs (Level 2) | | Significant Unobservable Inputs (Level 3) | Marketable equity securities — noncurrent | | $ | 34 |
| | $ | 34 |
| | $ | — |
| | $ | — |
| Marketable debt securities — noncurrent | | 22 |
| | 7 |
| | 15 |
| | — |
| | | $ | 56 |
| | $ | 41 |
| | $ | 15 |
| | $ | — |
|
| | | | | | | | | | | | | | | | | | Investments | | December 31, 2017 | | Quoted Prices
in Active
Markets for
Identical Assets
(Level 1) | | Significant Other
Observable Inputs
(Level 2) | | Significant
Unobservable
Inputs
(Level 3) | Marketable equity securities — noncurrent | | $ | 35 |
| | $ | 35 |
| | $ | — |
| | $ | — |
| Marketable debt securities — noncurrent | | 21 |
| | 7 |
| | 14 |
| | — |
| | | $ | 56 |
| | $ | 42 |
| | $ | 14 |
| | $ | — |
|
The following table presents this information and indicates the fair value hierarchy of the valuation techniques we utilized to determine such fair values. In general, fair values determined by Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities, which generally are not applicable to non-financial assets and liabilities. Fair values determined by Level 2 inputs utilize data points that are observable, such as definitive sales agreements, appraisals or established market values of comparable assets. Fair values determined by Level 3 inputs are unobservable data points for the asset or liability and include situations where there is little, if any, market activity for the asset or liability, such as internal estimates of future cash flows. | | | | | | | | | | | | | | | | | | | | March 31, 2018 | | Quoted Prices in Active Markets for Identical Assets (Level 1) | | Significant Other Observable Inputs (Level 2) | | Significant Unobservable Inputs (Level 3) | Long-lived assets held for sale | | $ | 423 |
| | $ | — |
| | $ | 423 |
| | $ | — |
| | | $ | 423 |
| | $ | — |
| | $ | 423 |
| | $ | — |
|
| | | | | | | | | | | | | | | | | |
| | December 31, 2017 | | Quoted Prices
in Active
Markets for
Identical Assets
(Level 1) | | Significant Other
Observable Inputs
(Level 2) | | Significant
Unobservable
Inputs
(Level 3) | Long-lived assets held for sale | | $ | 456 |
| | $ | — |
| | $ | 456 |
| | $ | — |
| Other than temporarily impaired equity method investments | | 113 |
| | — |
| | 113 |
| | — |
| | | $ | 569 |
| | $ | — |
| | $ | 569 |
| | $ | — |
|
|