Property and Casualty Insurance Reserves - Historical Claims Duration (Details)	Dec. 31, 2025
Specialty Personal Automobile Insurance—Liability
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	37.20%
Year 2	77.00%
Year 3	89.60%
Year 4	94.30%
Year 5	96.80%
Specialty Personal Automobile Insurance—Physical Damage
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	94.70%
Year 2	100.00%
Year 3	100.00%
Year 4	99.80%
Year 5	99.80%
Commercial Automobile Insurance—Liability
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	19.10%
Year 2	46.60%
Year 3	65.60%
Year 4	79.20%
Year 5	91.60%
Commercial Automobile Insurance—Physical Damage
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	87.20%
Year 2	100.00%
Year 3	100.00%
Year 4	100.00%
Year 5	100.00%
Preferred Personal Automobile Insurance—Liability
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	30.80%
Year 2	62.00%
Year 3	80.10%
Year 4	89.90%
Year 5	94.80%
Preferred Personal Automobile Insurance—Physical Damage
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	97.30%
Year 2	100.00%
Year 3	100.00%
Year 4	100.00%
Year 5	100.00%
Homeowners [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	67.50%
Year 2	93.00%
Year 3	97.10%
Year 4	98.40%
Year 5	98.80%

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.

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- Definition

Percentage of average annual payout, after reinsurance, in the fifth 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

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Percentage of average annual payout, after reinsurance, in the fourth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

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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

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Percentage of average annual payout, after reinsurance, in the third year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

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Percentage of average annual payout, after reinsurance, in the second year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

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