Investments (Fair Value Realized and Unrealized gain Losses) (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Net Investment Income [Line Items] | ||||
| Total | $ 55.3 | $ (29.8) | $ 111.1 | $ 83.3 |
| Vodafone | ||||
| Net Investment Income [Line Items] | ||||
| Total | 57.9 | (1.7) | 121.6 | 46.5 |
| ITV | ||||
| Net Investment Income [Line Items] | ||||
| Total | 43.1 | 33.1 | 79.8 | 83.1 |
| Televisa Univision | ||||
| Net Investment Income [Line Items] | ||||
| Total | (27.6) | 1.2 | (41.6) | 10.7 |
| Plume | ||||
| Net Investment Income [Line Items] | ||||
| Total | (9.7) | (26.7) | (13.0) | (27.8) |
| Lionsgate | ||||
| Net Investment Income [Line Items] | ||||
| Total | (9.5) | (4.1) | (7.3) | (10.1) |
| Aviatrix | ||||
| Net Investment Income [Line Items] | ||||
| Total | (4.0) | (13.2) | (3.8) | (27.5) |
| EdgeConneX | ||||
| Net Investment Income [Line Items] | ||||
| Total | 14.9 | 17.3 | 3.6 | 89.1 |
| SMAs | ||||
| Net Investment Income [Line Items] | ||||
| Total | 6.7 | 1.6 | 3.4 | 20.9 |
| Lacework | ||||
| Net Investment Income [Line Items] | ||||
| Total | 0.0 | (8.0) | 0.0 | (75.6) |
| Other, net | ||||
| Net Investment Income [Line Items] | ||||
| Total | $ (16.5) | $ (29.3) | $ (31.6) | $ (26.0) |