Marketable Securities and Other Investments - Net Unrealized Gains (Losses) (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Investments, Debt and Equity Securities [Abstract] | ||||
| Net unrealized (losses) gains | $ (8.5) | $ 6.4 | $ (4.7) | $ (8.6) |