Other Assets - Affordable Housing and Other Tax Credit Investment Partnerships 1 (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
Dec. 31, 2025 |
|
| Affordable housing and other tax credit investment partnership interests | |||||
| Investment partnership interest | $ 297.8 | $ 297.8 | $ 302.3 | ||
| Investment, Proportional Amortization Method, Elected, Statement of Financial Position [Extensible Enumeration] | Other Assets | Other Assets | Other Assets | ||
| Amortization | $ 8.9 | $ 7.6 | $ 17.9 | $ 15.2 | |
| Investment Program, Proportional Amortization Method, Applied, Amortization Expense, Statement of Income or Comprehensive Income [Extensible Enumeration] | Income Tax Expense (Benefit) | Income Tax Expense (Benefit) | Income Tax Expense (Benefit) | Income Tax Expense (Benefit) | |
| Affordable housing tax credits and other benefits recognized | $ 12.0 | $ 9.6 | $ 23.9 | $ 19.3 | |
| Investment Program, Proportional Amortization Method, Elected, Income Tax Credit and Other Income Tax Benefit, before Amortization, Statement of Income or Comprehensive Income [Extensible Enumeration] | Income Tax Expense (Benefit) | Income Tax Expense (Benefit) | Income Tax Expense (Benefit) | Income Tax Expense (Benefit) | |
| Investment Program, Proportional Amortization Method, Elected, Income Tax Credit and Other Income Tax Benefit, before Amortization, Statement of Cash Flows [Extensible Enumeration] | Net Income (Loss), Including Portion Attributable to Noncontrolling Interest | Net Income (Loss), Including Portion Attributable to Noncontrolling Interest | Net Income (Loss), Including Portion Attributable to Noncontrolling Interest | Net Income (Loss), Including Portion Attributable to Noncontrolling Interest | |