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Segment Information - Revenues (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Segment reporting information |  |  |
Earned insurance premiums | $ 1,691.6 | $ 1,440.9 | $ 1,076.7
Commission and fees revenues | 149.4 | 13.2 | 11.5
Other revenues | 55.8 | 69.0 | 124.0
Total | 1,896.8 | 1,523.1 | 1,212.2
United States |  |  |
Segment reporting information |  |  |
Earned insurance premiums | 2.8 | 5.2 | 5.8
Commission and fees revenues | 134.6 | 0.0 | 0.0
Other revenues | 55.8 | 69.0 | 124.0
Total | 193.2 | 74.2 | 129.8
United Kingdom |  |  |
Segment reporting information |  |  |
Earned insurance premiums | 956.8 | 791.7 | 638.5
Commission and fees revenues | 0.0 | 0.0 | 0.0
Other revenues | 0.0 | 0.0 | 0.0
Total | 956.8 | 791.7 | 638.5
Bermuda |  |  |
Segment reporting information |  |  |
Earned insurance premiums | 732.0 | 644.0 | 432.4
Commission and fees revenues | 0.0 | 0.0 | 0.0
Other revenues | 0.0 | 0.0 | 0.0
Total | 732.0 | 644.0 | 432.4
Other |  |  |
Segment reporting information |  |  |
Earned insurance premiums | 0.0 | 0.0 | 0.0
Commission and fees revenues | 14.8 | 13.2 | 11.5
Other revenues | 0.0 | 0.0 | 0.0
Total | $ 14.8 | $ 13.2 | $ 11.5

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- Definition Income from agency and brokerage operations (includes sales of annuities and supplemental contracts); service charges, commissions, and fees from the sale of insurance and related services; and management fees from separate accounts, deferred annuities, and universal life products. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 220 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04(13)(d)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 220 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04(13)(c)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1 + Details
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- Definition Amount, after premiums ceded to other entities and premiums assumed by the entity, of premiums earned. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.12-17(Column E)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477965/944-235-S99-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 605 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479032/944-605-50-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04(13)(c)) -SubTopic 220 -Topic 942 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(1)) -SubTopic 220 -Topic 944 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477250/944-220-S99-1 + Details
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