Fair value of assets and liabilities - Narrative (Details) $ in Millions |
3 Months Ended | |
|---|---|---|
|
Mar. 31, 2025
USD ($)
litigation_type
litigation_event
|
Dec. 31, 2024
USD ($)
|
|
| Fair Value Disclosures [Abstract] | ||
| Number of litigation events | litigation_event | 70 | |
| Number of litigation types | litigation_type | 5 | |
| Percentage of discrete objective litigation events | 10.00% | |
| Increase in income and net assets due to decrease in interest rate | $ | $ 461.5 | $ 466.3 |