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Reserve for Loss and Loss Expense - Schedule of Short-duration Insurance Contracts, Schedule of Historical Claims Duration (Details) | Dec. 31, 2024
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Standard Commercial Lines | General liability |
Short-duration Insurance Contracts, Historical Claims Duration [Line Items] |
Short-duration insurance contracts, Historical claims duration, year one | 5.80%
Short-duration insurance contracts, historical claims duration, year two | 11.00%
Short-duration insurance contracts, historical claims duration, year three | 14.00%
Short-duration insurance contracts, historical claims duration, year four | 16.20%
Short-duration insurance contracts, historical claims duration, year five | 14.10%
Short-duration insurance contracts, historical claims duration, year six | 10.30%
Short-duration insurance contracts, historical claims duration, year seven | 8.90%
Short-duration insurance contracts, historical claims duration, year eight | 5.00%
Short-duration insurance contracts, historical claims duration, year nine | 3.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year ten | 1.30%
Standard Commercial Lines | Workers Compensation |
Short-duration Insurance Contracts, Historical Claims Duration [Line Items] |
Short-duration insurance contracts, Historical claims duration, year one | 23.30%
Short-duration insurance contracts, historical claims duration, year two | 27.20%
Short-duration insurance contracts, historical claims duration, year three | 13.10%
Short-duration insurance contracts, historical claims duration, year four | 8.40%
Short-duration insurance contracts, historical claims duration, year five | 4.10%
Short-duration insurance contracts, historical claims duration, year six | 2.90%
Short-duration insurance contracts, historical claims duration, year seven | 2.40%
Short-duration insurance contracts, historical claims duration, year eight | 1.40%
Short-duration insurance contracts, historical claims duration, year nine | 0.90%
Short-duration Insurance Contracts, Historical Claims Duration, Year ten | 0.70%
Standard Commercial Lines | Commercial automobile |
Short-duration Insurance Contracts, Historical Claims Duration [Line Items] |
Short-duration insurance contracts, Historical claims duration, year one | 36.40%
Short-duration insurance contracts, historical claims duration, year two | 18.00%
Short-duration insurance contracts, historical claims duration, year three | 14.30%
Short-duration insurance contracts, historical claims duration, year four | 12.40%
Short-duration insurance contracts, historical claims duration, year five | 9.60%
Short-duration insurance contracts, historical claims duration, year six | 4.30%
Short-duration insurance contracts, historical claims duration, year seven | 2.10%
Short-duration insurance contracts, historical claims duration, year eight | 1.10%
Short-duration insurance contracts, historical claims duration, year nine | 0.70%
Short-duration Insurance Contracts, Historical Claims Duration, Year ten | 0.30%
Standard Commercial Lines | Businessowners’ policies |
Short-duration Insurance Contracts, Historical Claims Duration [Line Items] |
Short-duration insurance contracts, Historical claims duration, year one | 49.50%
Short-duration insurance contracts, historical claims duration, year two | 22.00%
Short-duration insurance contracts, historical claims duration, year three | 8.20%
Short-duration insurance contracts, historical claims duration, year four | 8.40%
Short-duration insurance contracts, historical claims duration, year five | 5.90%
Short-duration insurance contracts, historical claims duration, year six | 1.90%
Short-duration insurance contracts, historical claims duration, year seven | 1.90%
Short-duration insurance contracts, historical claims duration, year eight | 1.00%
Short-duration insurance contracts, historical claims duration, year nine | 0.50%
Short-duration Insurance Contracts, Historical Claims Duration, Year ten | 0.20%
Standard Commercial Lines | Commercial property |
Short-duration Insurance Contracts, Historical Claims Duration [Line Items] |
Short-duration insurance contracts, Historical claims duration, year one | 68.30%
Short-duration insurance contracts, historical claims duration, year two | 26.80%
Short-duration insurance contracts, historical claims duration, year three | 3.10%
Short-duration insurance contracts, historical claims duration, year four | 0.80%
Short-duration insurance contracts, historical claims duration, year five | 0.30%
Short-duration insurance contracts, historical claims duration, year six | 0.20%
Short-duration insurance contracts, historical claims duration, year seven | 0.10%
Short-duration insurance contracts, historical claims duration, year eight | 0.10%
Short-duration insurance contracts, historical claims duration, year nine | 0.10%
Short-duration Insurance Contracts, Historical Claims Duration, Year ten | 0.10%
Standard Personal Lines | Personal automobile |
Short-duration Insurance Contracts, Historical Claims Duration [Line Items] |
Short-duration insurance contracts, Historical claims duration, year one | 58.80%
Short-duration insurance contracts, historical claims duration, year two | 19.20%
Short-duration insurance contracts, historical claims duration, year three | 9.20%
Short-duration insurance contracts, historical claims duration, year four | 6.10%
Short-duration insurance contracts, historical claims duration, year five | 3.50%
Short-duration insurance contracts, historical claims duration, year six | 1.60%
Short-duration insurance contracts, historical claims duration, year seven | 0.40%
Short-duration insurance contracts, historical claims duration, year eight | 0.80%
Short-duration insurance contracts, historical claims duration, year nine | 0.20%
Short-duration Insurance Contracts, Historical Claims Duration, Year ten | 0.10%
Standard Personal Lines | Homeowners |
Short-duration Insurance Contracts, Historical Claims Duration [Line Items] |
Short-duration insurance contracts, Historical claims duration, year one | 71.20%
Short-duration insurance contracts, historical claims duration, year two | 22.90%
Short-duration insurance contracts, historical claims duration, year three | 3.30%
Short-duration insurance contracts, historical claims duration, year four | 1.10%
Short-duration insurance contracts, historical claims duration, year five | 1.00%
Short-duration insurance contracts, historical claims duration, year six | 0.20%
Short-duration insurance contracts, historical claims duration, year seven | 0.10%
Short-duration insurance contracts, historical claims duration, year eight | 0.10%
Short-duration insurance contracts, historical claims duration, year nine | 0.10%
Short-duration Insurance Contracts, Historical Claims Duration, Year ten | 0.10%
E&S Lines | Casualty lines |
Short-duration Insurance Contracts, Historical Claims Duration [Line Items] |
Short-duration insurance contracts, Historical claims duration, year one | 3.60%
Short-duration insurance contracts, historical claims duration, year two | 11.00%
Short-duration insurance contracts, historical claims duration, year three | 17.20%
Short-duration insurance contracts, historical claims duration, year four | 19.30%
Short-duration insurance contracts, historical claims duration, year five | 14.90%
Short-duration insurance contracts, historical claims duration, year six | 8.20%
Short-duration insurance contracts, historical claims duration, year seven | 8.40%
Short-duration insurance contracts, historical claims duration, year eight | 8.10%
Short-duration insurance contracts, historical claims duration, year nine | 2.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year ten | 1.80%

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- Definition Percentage of average annual payout, after reinsurance, in the eighth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 9F -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-9F Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4G -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4G + Details
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- Definition Percentage of average annual payout, after reinsurance, in the first year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 9F -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-9F Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4G -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4G + Details
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