The estimated fair value of financial instruments at December 31, 2019 was as follows: | | | | | | | | | | | | | | | | | | | | | | Fair Value Measurements at Reporting Date Using | (In millions) | | Total Carrying Amount | | Total Estimated Fair Value | | Quoted Prices in Active Markets for Identical Assets (Level 1) | | Significant Observable Inputs (Level 2) | Cash and cash equivalents | | $ | 490.8 |
| | $ | 490.8 |
| | $ | 490.8 |
| | $ | — |
| Derivative financial instruments: | | | | | | | | | Assets | | 5.6 |
| | 5.6 |
| | — |
| | 5.6 |
| Liabilities | | 7.5 |
| | 7.5 |
| | — |
| | 7.5 |
| Debt (a) | | 1,411.2 |
| | 1,676.5 |
| | 1,552.8 |
| | 123.7 |
|
The estimated fair value of financial instruments at December 31, 2018 was as follows: | | | | | | | | | | | | | | | | | | | | | | Fair Value Measurements at Reporting Date Using | (In millions) | | Total Carrying Amount | | Total Estimated Fair Value | | Quoted Prices in Active Markets for Identical Assets (Level 1) | | Significant Observable Inputs (Level 2) | Cash and cash equivalents | | $ | 382.0 |
| | $ | 382.0 |
| | $ | 382.0 |
| | $ | — |
| Derivative financial instruments: | | | | | | | | | Assets | | 3.4 |
| | 3.4 |
| | — |
| | 3.4 |
| Liabilities | | 10.4 |
| | 10.4 |
| | — |
| | 10.4 |
| Debt (a) | | 1,552.5 |
| | 1,739.4 |
| | 1,624.4 |
| | 115.0 |
|
|