Stock-based compensation - expense (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Other information about options outstanding | ||||
| Expense | $ 15.4 | $ 15.5 | $ 24.0 | $ 27.9 |
| Equity Award | ||||
| Other information about options outstanding | ||||
| Expense | 15.2 | 15.8 | 24.2 | 28.8 |
| Stock options | ||||
| Other information about options outstanding | ||||
| Expense | 1.9 | 2.4 | 3.4 | 4.8 |
| RSUs | ||||
| Other information about options outstanding | ||||
| Expense | 13.0 | 13.1 | 20.3 | 23.4 |
| Other | ||||
| Other information about options outstanding | ||||
| Expense | 0.5 | 0.0 | 0.3 | (0.3) |
| Liability Award | ||||
| Other information about options outstanding | ||||
| Expense | $ 0.2 | $ (0.3) | $ (0.2) | $ (0.9) |