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Investment Securities - Other long-term investments (Details) - USD ($) $ in Millions | Mar. 31, 2021 | Dec. 31, 2020
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Debt and Equity Securities, FV-NI [Line Items] |  |
Other Long-term Investments | $ 1,032.2 | $ 786.8
Asset Management (Kudu) |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Other Long-term Investments | 427.4 | 400.6
PassportCard/DavidShield |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Other Long-term Investments | 95.0 | 95.0
Elementum Holdings L.P. |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Other Long-term Investments | 56.7 | 55.1
Other unconsolidated entities |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Other Long-term Investments | 43.3 | 42.4
Total unconsolidated entities |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Other Long-term Investments | 622.4 | 593.1
Private equity funds and hedge funds |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Other Long-term Investments | 133.5 | 121.2
Lloyd’s trust deposits |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Other Long-term Investments | 99.2 | 0.0
Bank loan fund |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Other Long-term Investments | 89.2 | 0.0
ILS funds |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Other Long-term Investments | 53.8 | 51.4
Private debt instruments |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Other Long-term Investments | 21.0 | 21.1
Other |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Other Long-term Investments | $ 13.1 | $ 0.0

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- Definition Amount of long-term investments classified as other. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1(f)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.12) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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