Liability for Losses and Loss Expenses, Supplementary Information About Average Historical Claims Duration (Details)	Dec. 31, 2023
Personal Automobile [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Abstract]
Average annual percentage payout of incurred claims by age, net of reinsurance, year 1	65.60%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 2	16.90%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 3	8.50%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 4	4.20%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 5	2.20%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 6	0.90%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 7	0.50%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 8	0.10%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 9	0.40%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 10	0.30%
Homeowners [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Abstract]
Average annual percentage payout of incurred claims by age, net of reinsurance, year 1	81.10%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 2	16.00%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 3	1.20%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 4	0.50%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 5	0.20%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 6	0.20%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 7	0.10%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 8	0.00%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 9	0.10%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 10	0.00%
Commercial Automobile [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Abstract]
Average annual percentage payout of incurred claims by age, net of reinsurance, year 1	42.30%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 2	18.10%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 3	14.40%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 4	11.90%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 5	6.20%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 6	3.70%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 7	1.40%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 8	0.40%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 9	0.00%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 10	0.10%
Commercial Multi-Peril [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Abstract]
Average annual percentage payout of incurred claims by age, net of reinsurance, year 1	44.30%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 2	17.60%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 3	9.80%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 4	10.30%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 5	6.60%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 6	3.40%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 7	2.10%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 8	0.80%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 9	1.50%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 10	0.40%
Workers Compensation [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Abstract]
Average annual percentage payout of incurred claims by age, net of reinsurance, year 1	30.90%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 2	32.60%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 3	15.60%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 4	8.10%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 5	3.30%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 6	1.90%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 7	1.10%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 8	0.80%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 9	1.00%
Average annual percentage payout of incurred claims by age, net of reinsurance, year 10	1.20%

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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://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 4G
-SubTopic 40
-Topic 944
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480081/944-40-50-4G

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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.

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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.

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Percentage of average annual payout, after reinsurance, in the ninth 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.

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- Definition

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

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

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- Definition

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

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- Definition

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.

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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.

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