XML 67 R57.htm IDEA: XBRL DOCUMENT
v3.24.2.u1

Investments in Fixed Maturity Securities (Amortized cost and fair value of fixed maturity securities) (Details) - USD ($) $ in Thousands | Jun. 30, 2024 | Mar. 31, 2024 | Dec. 31, 2023 | Jun. 30, 2023 | Mar. 31, 2023 | Dec. 31, 2022
--- | --- | --- | --- | --- | --- | ---
Investments, Debt and Equity Securities [Abstract] |  |  |  |  |  |
Amortized Cost, Due in one year or less | $ 1,943,246 |  |  |  |  |
Amortized Cost, Due after one year through five years | 9,983,542 |  |  |  |  |
Amortized Cost, Due after five years through ten years | 4,262,692 |  |  |  |  |
Amortized Cost, Due after ten years | 2,945,631 |  |  |  |  |
Amortized Cost, Mortgaged-backed securities | 2,776,272 |  |  |  |  |
Total investments in fixed maturity securities, Amortized Value | 21,911,383 |  |  |  |  |
Fair Value, Due in one year or less | 1,884,790 |  |  |  |  |
Fair Value, Due after one year through five years | 9,601,275 |  |  |  |  |
Fair Value, Due after five years through ten years | 4,152,066 |  |  |  |  |
Fair Value, Due after ten years | 2,850,702 |  |  |  |  |
Fair Value, Mortgage-backed securities | 2,595,669 |  |  |  |  |
Total investments in fixed maturity securities, Fair Value | 21,084,502 |  | $ 20,181,547 |  |  |
Cumulative effect adjustment resulting from changes in accounting principles | $ 34 | $ 38 | $ 43 | $ 53 | $ 107 | $ 114

X
- Definition Fair value of investment in debt security measured at amortized cost (held-to-maturity) and investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5A -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5A Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (aa) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-2 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleAndHeldToMaturityFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of allowance for credit loss for debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (aaa) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479344/326-20-45-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Debt Securities, Available-for-sale and Held-to-maturity, Amortized Cost, Net + References No definition available. + Details
Name: | wrb_DebtSecuritiesAvailableforsaleandHeldtomaturityAmortizedCostNet
Namespace Prefix: | wrb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Marketable Securities Debt Maturities Without Single Maturity Date Amortized Cost + References No definition available. + Details
Name: | wrb_MarketableSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost
Namespace Prefix: | wrb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Marketable Securities Debt Maturities Without Single Maturity Date Fair Value + References No definition available. + Details
Name: | wrb_MarketableSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue
Namespace Prefix: | wrb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Marketable Securities Fixed Maturities After Five Through Ten Years Amortized Cost + References No definition available. + Details
Name: | wrb_MarketableSecuritiesFixedMaturitiesAfterFiveThroughTenYearsAmortizedCost
Namespace Prefix: | wrb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Marketable Securities Fixed Maturities After Five Through Ten Years Fair Value + References No definition available. + Details
Name: | wrb_MarketableSecuritiesFixedMaturitiesAfterFiveThroughTenYearsFairValue
Namespace Prefix: | wrb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Marketable Securities Fixed Maturities After One Through Five Years Amortized Cost + References No definition available. + Details
Name: | wrb_MarketableSecuritiesFixedMaturitiesAfterOneThroughFiveYearsAmortizedCost
Namespace Prefix: | wrb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Marketable Securities Fixed Maturities After One Through Five Years Fair Value + References No definition available. + Details
Name: | wrb_MarketableSecuritiesFixedMaturitiesAfterOneThroughFiveYearsFairValue
Namespace Prefix: | wrb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Marketable Securities Fixed Maturities After Ten Years Amortized Cost + References No definition available. + Details
Name: | wrb_MarketableSecuritiesFixedMaturitiesAfterTenYearsAmortizedCost
Namespace Prefix: | wrb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Marketable Securities Fixed Maturities After Ten Years Fair Value + References No definition available. + Details
Name: | wrb_MarketableSecuritiesFixedMaturitiesAfterTenYearsFairValue
Namespace Prefix: | wrb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Marketable Securities Fixed Maturities Within One Year Amortized Cost + References No definition available. + Details
Name: | wrb_MarketableSecuritiesFixedMaturitiesWithinOneYearAmortizedCost
Namespace Prefix: | wrb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Marketable Securities Fixed Maturities Within One Year Fair Value + References No definition available. + Details
Name: | wrb_MarketableSecuritiesFixedMaturitiesWithinOneYearFairValue
Namespace Prefix: | wrb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant