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Fair Value Measurements - Financial Assets Measured on Recurring Basis (Details) - USD ($) $ in Millions | Jun. 30, 2017 | Dec. 31, 2016 | Jun. 30, 2016
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Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Catastrophe bonds trading, at fair value | $ 28.3 | $ 42.5 |
Derivatives at fair value | 22.1 | 7.2 |
Fair Value, Measurements, Recurring |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Catastrophe bonds trading, at fair value | 28.3 |  |
Loan notes issued by variable interest entities, at fair value | (110.8) | (115.0) |
Loan notes issued by variable interest entities, at fair value (included within accrued expenses and other payables) | (4.7) | (108.4) |
Total | (7,555.4) | (7,653.6) |
Fair Value, Measurements, Recurring | Short-term investments trading, at fair value |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 73.7 | 185.4 |
Fair Value, Measurements, Recurring | Equity investments trading, at fair value |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 658.7 | 584.7 |
Fair Value, Measurements, Recurring | Derivatives at fair value, assets | Foreign Exchange Contracts |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Derivatives at fair value | 22.1 | 7.2 |
Fair Value, Measurements, Recurring | Liabilities under derivative contracts — foreign exchange contracts | Foreign Exchange Contracts |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Liabilities under derivative contracts, fair value | (8.6) | (18.4) |
Available for sale financial assets | Fair Value, Measurements, Recurring |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 5,497.3 | 5,664.6 |
Available for sale financial assets | Fair Value, Measurements, Recurring | U.S. government |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 1,220.8 | 1,206.1 |
Available for sale financial assets | Fair Value, Measurements, Recurring | U.S. agency |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 75.5 | 119.6 |
Available for sale financial assets | Fair Value, Measurements, Recurring | Municipal |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 32.8 | 24.4 |
Available for sale financial assets | Fair Value, Measurements, Recurring | Corporate |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 2,503.4 | 2,586.5 |
Available for sale financial assets | Fair Value, Measurements, Recurring | Non-U.S. government-backed corporate |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 92.6 | 89.8 |
Available for sale financial assets | Fair Value, Measurements, Recurring | Non-U.S. government |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 525.9 | 488.7 |
Available for sale financial assets | Fair Value, Measurements, Recurring | Asset-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 48.9 | 63.0 |
Available for sale financial assets | Fair Value, Measurements, Recurring | Non-agency commercial mortgage-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 4.3 | 12.6 |
Available for sale financial assets | Fair Value, Measurements, Recurring | Agency mortgage-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 993.1 | 1,073.9 |
Short-term investments | Fair Value, Measurements, Recurring |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 41.9 | 145.3 |
Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 1,357.5 | 1,265.7 |
Catastrophe bonds trading, at fair value |  | 42.5 |
Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | U.S. government |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 112.8 | 82.4 |
Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | U.S. agency |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 |  |
Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Municipal |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 5.7 | 15.5 |
Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Corporate |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 895.9 | 820.6 |
Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Non-U.S. government-backed corporate |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 2.0 |  |
Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Non-U.S. government |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 186.5 | 202.8 |
Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Asset-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 12.2 | 14.5 |
Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Agency mortgage-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 142.4 | 129.9 |
Level 1 | Fair Value, Measurements, Recurring |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Catastrophe bonds trading, at fair value | 0.0 |  |
Loan notes issued by variable interest entities, at fair value | 0.0 | 0.0 |
Loan notes issued by variable interest entities, at fair value (included within accrued expenses and other payables) | 0.0 | 0.0 |
Total | (2,479.1) | (2,411.6) |
Level 1 | Fair Value, Measurements, Recurring | Short-term investments trading, at fair value |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 73.5 | 76.1 |
Level 1 | Fair Value, Measurements, Recurring | Equity investments trading, at fair value |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 658.7 | 584.7 |
Level 1 | Fair Value, Measurements, Recurring | Derivatives at fair value, assets | Foreign Exchange Contracts |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Derivatives at fair value | 0.0 | 0.0 |
Level 1 | Fair Value, Measurements, Recurring | Liabilities under derivative contracts — foreign exchange contracts | Foreign Exchange Contracts |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Liabilities under derivative contracts, fair value | 0.0 | 0.0 |
Level 1 | Available for sale financial assets | Fair Value, Measurements, Recurring |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 1,594.3 | 1,549.8 |
Level 1 | Available for sale financial assets | Fair Value, Measurements, Recurring | U.S. government |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 1,220.8 | 1,206.1 |
Level 1 | Available for sale financial assets | Fair Value, Measurements, Recurring | U.S. agency |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 1 | Available for sale financial assets | Fair Value, Measurements, Recurring | Municipal |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 1 | Available for sale financial assets | Fair Value, Measurements, Recurring | Corporate |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 1 | Available for sale financial assets | Fair Value, Measurements, Recurring | Non-U.S. government-backed corporate |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 1 | Available for sale financial assets | Fair Value, Measurements, Recurring | Non-U.S. government |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 373.5 | 343.7 |
Level 1 | Available for sale financial assets | Fair Value, Measurements, Recurring | Asset-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 1 | Available for sale financial assets | Fair Value, Measurements, Recurring | Non-agency commercial mortgage-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 1 | Available for sale financial assets | Fair Value, Measurements, Recurring | Agency mortgage-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 1 | Short-term investments | Fair Value, Measurements, Recurring |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 38.1 | 118.6 |
Level 1 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 114.5 | 82.4 |
Catastrophe bonds trading, at fair value |  | 0.0 |
Level 1 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | U.S. government |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 112.8 | 82.4 |
Level 1 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | U.S. agency |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 |  |
Level 1 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Municipal |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 1 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Corporate |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 1 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Non-U.S. government-backed corporate |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 |  |
Level 1 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Non-U.S. government |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 1.7 | 0.0 |
Level 1 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Asset-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 1 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Agency mortgage-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 2 | Fair Value, Measurements, Recurring |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Catastrophe bonds trading, at fair value | 28.3 |  |
Loan notes issued by variable interest entities, at fair value | 0.0 | 0.0 |
Loan notes issued by variable interest entities, at fair value (included within accrued expenses and other payables) | 0.0 | 0.0 |
Total | (5,191.8) | (5,465.4) |
Level 2 | Fair Value, Measurements, Recurring | Short-term investments trading, at fair value |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.2 | 109.3 |
Level 2 | Fair Value, Measurements, Recurring | Equity investments trading, at fair value |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 2 | Fair Value, Measurements, Recurring | Derivatives at fair value, assets | Foreign Exchange Contracts |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Derivatives at fair value | 22.1 | 7.2 |
Level 2 | Fair Value, Measurements, Recurring | Liabilities under derivative contracts — foreign exchange contracts | Foreign Exchange Contracts |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Liabilities under derivative contracts, fair value | (8.6) | (18.4) |
Level 2 | Available for sale financial assets | Fair Value, Measurements, Recurring |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 3,903.0 | 4,114.8 |
Level 2 | Available for sale financial assets | Fair Value, Measurements, Recurring | U.S. government |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 2 | Available for sale financial assets | Fair Value, Measurements, Recurring | U.S. agency |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 75.5 | 119.6 |
Level 2 | Available for sale financial assets | Fair Value, Measurements, Recurring | Municipal |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 32.8 | 24.4 |
Level 2 | Available for sale financial assets | Fair Value, Measurements, Recurring | Corporate |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 2,503.4 | 2,586.5 |
Level 2 | Available for sale financial assets | Fair Value, Measurements, Recurring | Non-U.S. government-backed corporate |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 92.6 | 89.8 |
Level 2 | Available for sale financial assets | Fair Value, Measurements, Recurring | Non-U.S. government |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 152.4 | 145.0 |
Level 2 | Available for sale financial assets | Fair Value, Measurements, Recurring | Asset-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 48.9 | 63.0 |
Level 2 | Available for sale financial assets | Fair Value, Measurements, Recurring | Non-agency commercial mortgage-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 4.3 | 12.6 |
Level 2 | Available for sale financial assets | Fair Value, Measurements, Recurring | Agency mortgage-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 993.1 | 1,073.9 |
Level 2 | Short-term investments | Fair Value, Measurements, Recurring |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 3.8 | 26.7 |
Level 2 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 1,243.0 | 1,183.3 |
Catastrophe bonds trading, at fair value |  | 42.5 |
Level 2 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | U.S. government |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 2 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | U.S. agency |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 |  |
Level 2 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Municipal |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 5.7 | 15.5 |
Level 2 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Corporate |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 895.9 | 820.6 |
Level 2 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Non-U.S. government-backed corporate |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 2.0 |  |
Level 2 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Non-U.S. government |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 184.8 | 202.8 |
Level 2 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Asset-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 12.2 | 14.5 |
Level 2 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Agency mortgage-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 142.4 | 129.9 |
Level 3 | Fair Value, Measurements, Recurring |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Catastrophe bonds trading, at fair value | 0.0 |  |
Loan notes issued by variable interest entities, at fair value | (110.8) | (115.0) |
Loan notes issued by variable interest entities, at fair value (included within accrued expenses and other payables) | (4.7) | (108.4) | $ (1.4)
Total | (115.5) | (223.4) |
Level 3 | Fair Value, Measurements, Recurring | Short-term investments trading, at fair value |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 3 | Fair Value, Measurements, Recurring | Equity investments trading, at fair value |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 3 | Fair Value, Measurements, Recurring | Derivatives at fair value, assets | Foreign Exchange Contracts |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Derivatives at fair value | 0.0 | 0.0 |
Level 3 | Fair Value, Measurements, Recurring | Liabilities under derivative contracts — foreign exchange contracts | Foreign Exchange Contracts |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Liabilities under derivative contracts, fair value | 0.0 | 0.0 |
Level 3 | Available for sale financial assets | Fair Value, Measurements, Recurring |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 3 | Available for sale financial assets | Fair Value, Measurements, Recurring | U.S. government |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 3 | Available for sale financial assets | Fair Value, Measurements, Recurring | U.S. agency |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 3 | Available for sale financial assets | Fair Value, Measurements, Recurring | Municipal |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 3 | Available for sale financial assets | Fair Value, Measurements, Recurring | Corporate |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 3 | Available for sale financial assets | Fair Value, Measurements, Recurring | Non-U.S. government-backed corporate |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 3 | Available for sale financial assets | Fair Value, Measurements, Recurring | Non-U.S. government |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 3 | Available for sale financial assets | Fair Value, Measurements, Recurring | Asset-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 3 | Available for sale financial assets | Fair Value, Measurements, Recurring | Non-agency commercial mortgage-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 3 | Available for sale financial assets | Fair Value, Measurements, Recurring | Agency mortgage-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 3 | Short-term investments | Fair Value, Measurements, Recurring |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 3 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Catastrophe bonds trading, at fair value |  | 0.0 |
Level 3 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | U.S. government |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 3 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | U.S. agency |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 |  |
Level 3 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Municipal |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 3 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Corporate |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 3 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Non-U.S. government-backed corporate |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 |  |
Level 3 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Non-U.S. government |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 3 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Asset-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | 0.0 | 0.0 |
Level 3 | Held for trading financial assets, at fair value | Fair Value, Measurements, Recurring | Agency mortgage-backed |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investments, at fair value | $ 0.0 | $ 0.0 |

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