Investment Securities - Gross Gains and (Losses) on Sales of Investments (Detail) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Investment securities - AFS | ||||
| Gross gains | $ 11.8 | $ 2.7 | $ 13.9 | $ 3.6 |
| Gross losses | 0.0 | (0.4) | 0.0 | (2.2) |
| Net gain on AFS securities | 11.8 | 2.3 | 13.9 | 1.4 |
| Equity securities | ||||
| Gross gains | 0.2 | 0.0 | 0.2 | 0.0 |
| Gross losses | (0.6) | 0.0 | (0.6) | 0.0 |
| Net loss on equity securities | $ (0.4) | $ 0.0 | $ (0.4) | $ 0.0 |
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount of realized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount of realized gain from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount of realized gain (loss) from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of realized loss from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|