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Investment Securities - Fair Value of Hedge Funds Subject to Restrictions on Redemption Frequency (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022
--- | --- | ---
Private equity funds |  |
Investment securities |  |
Fair Value | $ 248.6 | $ 140.6
Unfunded Commitments | 57.7 | 94.3
Hedge funds |  |
Investment securities |  |
Fair Value | 64.3 | 57.2
Unfunded Commitments | 0.0 | 0.0
Aerospace/Defense/Government | Private equity funds |  |
Investment securities |  |
Fair Value | 157.2 | 59.4
Unfunded Commitments | 17.4 | 37.5
Financial services | Private equity funds |  |
Investment securities |  |
Fair Value | 87.5 | 77.1
Unfunded Commitments | 37.8 | 54.3
Real estate | Private equity funds |  |
Investment securities |  |
Fair Value | 3.9 | 4.1
Unfunded Commitments | 2.5 | 2.5
Long/short equity financials and business services | Hedge funds |  |
Investment securities |  |
Fair Value | 54.4 | 49.0
Unfunded Commitments | 0.0 | 0.0
European small/mid cap | Hedge funds |  |
Investment securities |  |
Fair Value | 9.9 | 8.2
Unfunded Commitments | 0.0 | 0.0
Private equity funds and hedge funds |  |
Investment securities |  |
Fair Value | 312.9 | 197.8
Unfunded Commitments | $ 57.7 | $ 94.3

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- Definition The amount of unfunded commitments for which the entity is obligated, to those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 6A -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-6A + Details
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