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Reserves for Losses and Adjustment Expenses Short-duration Contracts - Historical Claims Duration (Details) | Dec. 31, 2017
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Insurance |
Short-duration Insurance Contracts, Historical Claims Duration [Line Items] |
Average Annual Percentage Payout of Incurred Claims, Net of Reinsurance, Year One | 15.40%
Average Annual Percentage Payout of Incurred Claims, Net of Reinsurance, Year Two | 25.30%
Average Annual Percentage Payout of Incurred Claims, Net of Reinsurance, Year Three | 16.30%
Average Annual Percentage Payout of Incurred Claims, Net of Reinsurance, Year Four | 12.20%
Average Annual Percentage Payout of Incurred Claims, Net of Reinsurance, Year Five | 7.60%
Average Annual Percentage Payout of Incurred Claims, Net of Reinsurance, Year Six | 3.40%
Reinsurance |
Short-duration Insurance Contracts, Historical Claims Duration [Line Items] |
Average Annual Percentage Payout of Incurred Claims, Net of Reinsurance, Year One | 13.20%
Average Annual Percentage Payout of Incurred Claims, Net of Reinsurance, Year Two | 25.00%
Average Annual Percentage Payout of Incurred Claims, Net of Reinsurance, Year Three | 17.00%
Average Annual Percentage Payout of Incurred Claims, Net of Reinsurance, Year Four | 8.10%
Average Annual Percentage Payout of Incurred Claims, Net of Reinsurance, Year Five | 7.10%
Average Annual Percentage Payout of Incurred Claims, Net of Reinsurance, Year Six | 5.50%

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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/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4G -URI http://asc.fasb.org/extlink&oid=65670685&loc=SL65671329-158438 + Details
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- Definition 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 Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4G -URI http://asc.fasb.org/extlink&oid=65670685&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4G -URI http://asc.fasb.org/extlink&oid=65670685&loc=SL65671329-158438 + Details
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- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4G -URI http://asc.fasb.org/extlink&oid=65670685&loc=SL65671329-158438 + Details
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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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4G -URI http://asc.fasb.org/extlink&oid=65670685&loc=SL65671329-158438 + Details
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- Definition 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 Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4G -URI http://asc.fasb.org/extlink&oid=65670685&loc=SL65671329-158438 + Details
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