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Investment Securities - Fair Value of Hedge Funds and Private Equity Funds (Details) - USD ($) $ in Millions | Jun. 30, 2023 | Dec. 31, 2022
--- | --- | ---
Total private equity funds and hedge funds included in other long-term investments |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Fair Value | $ 289.3 | $ 197.8
Unfunded Commitments | 79.7 | 94.3
Private equity funds |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Fair Value | 229.7 | 140.6
Unfunded Commitments | 79.7 | 94.3
Private equity funds | Aerospace/Defense/Government |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Fair Value | 139.8 | 59.4
Unfunded Commitments | 32.3 | 37.5
Private equity funds | Financial services |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Fair Value | 85.7 | 77.1
Unfunded Commitments | 44.9 | 54.3
Private equity funds | Real estate |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Fair Value | 4.2 | 4.1
Unfunded Commitments | 2.5 | 2.5
Hedge funds |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Fair Value | 59.6 | 57.2
Unfunded Commitments | 0.0 | 0.0
Hedge funds | Long/short equity financials and business services |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Fair Value | 49.8 | 49.0
Unfunded Commitments | 0.0 | 0.0
Hedge funds | European small/mid cap |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Fair Value | 9.8 | 8.2
Unfunded Commitments | $ 0.0 | $ 0.0

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