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Investment Securities - Fair Value of Hedge Funds Subject to Restrictions on Redemption Frequency (Details) - USD ($) $ in Millions | Dec. 31, 2025 | Dec. 31, 2024
--- | --- | ---
Private equity funds |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Fair Value | $ 251.2 | $ 249.5
Unfunded Commitments | 65.8 | 83.7
Hedge funds |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Fair Value | 144.0 | 111.1
Unfunded Commitments | 0.0 | 0.0
Aerospace/Defense/Government | Private equity funds |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Fair Value | 144.0 | 152.4
Unfunded Commitments | 39.9 | 49.3
Financial services | Private equity funds |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Fair Value | 104.2 | 93.4
Unfunded Commitments | 23.7 | 32.0
Real estate | Private equity funds |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Fair Value | 3.0 | 3.7
Unfunded Commitments | 2.2 | 2.4
Long/short all cap global | Hedge funds |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Fair Value | 110.6 | 51.9
Unfunded Commitments | 0.0 | 0.0
Long/short equity financials and business services | Hedge funds |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Fair Value | 33.4 | 59.2
Unfunded Commitments | 0.0 | 0.0
Total private equity funds and hedge funds |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Fair Value | 395.2 | 360.6
Unfunded Commitments | $ 65.8 | $ 83.7

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