Pledged Assets, Accepted Collateral and Restricted Assets (Accepted Collateral) (Details) - USD ($) $ in Millions |
Jun. 30, 2025 |
Dec. 31, 2024 |
|---|---|---|
| Financial Instruments Owned and Pledged as Collateral [Line Items] | ||
| Total Collateral Accepted | $ 64,944.9 | $ 65,334.7 |
| Reverse repurchase agreements | ||
| Financial Instruments Owned and Pledged as Collateral [Line Items] | ||
| Collateral that may be repledged or sold | 64,939.6 | 65,311.1 |
| Collateral that may not be repledged or sold | 0.0 | 0.0 |
| Fair value of securities received as collateral that have been resold or repledged | 64,500.0 | 64,800.0 |
| Derivative contracts | ||
| Financial Instruments Owned and Pledged as Collateral [Line Items] | ||
| Collateral that may be repledged or sold | $ 5.3 | $ 23.6 |