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Reserve for Claims and Claim Expenses (Historical Claims Duration) (Details) | Dec. 31, 2018
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Property |
Short-duration Insurance Contracts, Historical Claims Duration [Line Items] |
Average annual percentage payout, year one | 31.70%
Average annual percentage payout, year two | 17.30%
Average annual percentage payout, year three | 20.80%
Average annual percentage payout, year four | 9.10%
Average annual percentage payout, year five | 5.20%
Average annual percentage payout, year six | 3.30%
Average annual percentage payout, year seven | 4.70%
Average annual percentage payout, year eight | 0.90%
Average annual percentage payout, year nine | 2.00%
Average annual percentage payout, year ten | 0.40%
Casualty and Specialty |
Short-duration Insurance Contracts, Historical Claims Duration [Line Items] |
Average annual percentage payout, year one | 10.10%
Average annual percentage payout, year two | 16.90%
Average annual percentage payout, year three | 12.90%
Average annual percentage payout, year four | 10.90%
Average annual percentage payout, year five | 8.50%
Average annual percentage payout, year six | 10.00%
Average annual percentage payout, year seven | 5.10%
Average annual percentage payout, year eight | 3.60%
Average annual percentage payout, year nine | 1.60%
Average annual percentage payout, year ten | 2.20%

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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://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4G -URI http://asc.fasb.org/extlink&oid=99384497&loc=SL65671329-158438 + 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://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4G -URI http://asc.fasb.org/extlink&oid=99384497&loc=SL65671329-158438 + Details
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