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Schedule VI. Supplemental Information Concerning Property and Casualty Insurance Operations (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020
Incurred claim and claim adjustment expenses related to current year | $ 6,243 | $ 5,970 | $ 5,793
Incurred claim and claim adjustment expenses related to prior years | (187) | (104) | (119)
Consolidated Property and Casualty Insurance Entity |  |  |
Deferred acquisition costs | 806 | 737 |
Reserves for unpaid claim and claim adjustment expenses | 25,099 | 24,174 |
Discount deducted from claim and claim adjustment expense reserves above (based on interest rates ranging from 3.5% to 6.4%) | 1,133 | 1,146 |
Unearned premiums | 6,374 | 5,761 |
Net written premiums | 9,128 | 8,405 | 8,059
Net earned premiums | 8,667 | 8,175 | 7,649
Net investment income | 1,751 | 2,111 | 1,896
Incurred claim and claim adjustment expenses related to current year |  | 5,970 | 5,793
Incurred claim and claim adjustment expenses related to prior years |  | (104) | (119)
Amortization of deferred acquisition costs | $ 1,490 | 1,443 | 1,410
Paid claim and claim adjustment expenses |  | $ 4,844 | $ 5,164
Consolidated Property and Casualty Insurance Entity | Minimum |  |  |
Supplemental Information Parenthetical |  |  |
SEC Schedule, 12-18, supplemental information, property-casualty insurance underwriters, interest rate at which discount computed | 3.50% | 3.50% |
Consolidated Property and Casualty Insurance Entity | Maximum |  |  |
Supplemental Information Parenthetical |  |  |
SEC Schedule, 12-18, supplemental information, property-casualty insurance underwriters, interest rate at which discount computed | 6.40% | 6.40% |

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- Definition Amount of amortization expense on deferred policy acquisition cost for property-casualty insurance underwriter. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 235 -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-18(Column I)) -URI https://asc.fasb.org/extlink&oid=120401096&loc=d3e575016-122915 + Details
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- Definition Amount, after effects of reinsurance, of expense for claims incurred in the current reporting period and related claims settlement costs. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437 + Details
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- Definition Amount of deferred policy acquisition cost related to property-casualty insurance policy written. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 235 -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-18(Column B)) -URI https://asc.fasb.org/extlink&oid=120401096&loc=d3e575016-122915 + Details
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- Definition Amount of discount deducted from reserve for unpaid claim and claim adjustment expense by property-casualty insurance underwriter. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 235 -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-18(Column D)) -URI https://asc.fasb.org/extlink&oid=120401096&loc=d3e575016-122915 + Details
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- Definition Amount of loss reported and paid for claim and claim adjustment expense by property-casualty insurance underwriter. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 235 -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-18(Column J)) -URI https://asc.fasb.org/extlink&oid=120401096&loc=d3e575016-122915 + Details
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