$MKL
MARKEL GROUP INC. Stock $mkl

$mkl Overview Financials Valuation SEC Filings Company Website

2023 Q1 Form 10-K Financial Statement

#000109634323000033 Filed on February 17, 2023

Income Statement

Concept	2023 Q1	2022 Q4	2022
Revenue	$3.643B	$4.211B	$11.68B
YoY Change	39.8%	12.12%	-9.12%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$422.1M	$43.79M	$178.8M
YoY Change	10.46%	4.28%	-87.4%
% of Gross Profit
Operating Expenses	$2.889B	$3.075B	$11.69B
YoY Change	9.1%	19.15%	21.72%
Operating Profit	$753.9M		-$92.99M
YoY Change	-1888.81%		-102.87%
Interest Expense	$49.44M	-$154.1M	-$55.85M
YoY Change	-0.51%	341.35%	-130.42%
% of Operating Profit	6.56%
Other Income/Expense, Net
YoY Change
Pretax Income	$671.5M	$901.5M	-$148.8M
YoY Change	-1082.59%	-20.9%	-104.75%
Income Tax	$133.7M	$191.9M	-$47.64M
% Of Pretax Income	19.91%	21.29%
Net Earnings	$488.7M	$664.0M	-$320.0M
YoY Change	-1024.72%	-23.78%	-113.2%
Net Earnings / Revenue	13.41%	15.77%	-2.74%
Basic Earnings Per Share	$37.33		-$23.57
Diluted Earnings Per Share	$37.26	$49.05M	-$23.57M
COMMON SHARES
Basic Shares Outstanding	13.41M shares	13.45M shares	13.58M shares
Diluted Shares Outstanding	13.48M shares		13.58M shares

Balance Sheet

Concept	2023 Q1	2022 Q4	2022
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$4.032B	$4.137B	$4.137B
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory		$639.6M
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment		$1.200B	$1.727B
YoY Change		9.09%
Goodwill	$2.643B	$2.639B
YoY Change	-4.71%	-8.98%
Intangibles	$1.706B	$1.747B
YoY Change	-3.81%	-4.12%
Long-Term Investments	$491.8M	$494.0M	$22.20B
YoY Change	0.47%	7.46%	-5.18%
Other Assets	$972.9M	$1.084B	$1.121B
YoY Change	-26.1%	20.13%	24.25%
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$50.94B	$49.79B	$49.79B
YoY Change	4.0%	2.71%	2.71%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses			$554.4M
YoY Change
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due			$399.6M
YoY Change
Total Short-Term Liabilities			$954.0M
YoY Change
LONG-TERM LIABILITIES
Long-Term Debt	$3.897B	$4.104B	$3.704B
YoY Change	-12.01%	-5.91%	-15.07%
Other Long-Term Liabilities	$4.087B	$4.198B	$2.769B
YoY Change	-10.55%	-11.35%	-41.51%
Total Long-Term Liabilities	$7.984B	$8.301B	$6.473B
YoY Change	-11.27%	-8.74%	-28.84%
TOTAL LIABILITIES
Total Short-Term Liabilities			$954.0M
Total Long-Term Liabilities	$7.984B	$8.301B	$6.473B
Total Liabilities	$36.66B	$36.14B	$36.73B
YoY Change	6.58%	8.61%	8.79%
SHAREHOLDERS EQUITY
Retained Earnings	$10.26B	$9.837B
YoY Change	-0.22%	-5.84%
Common Stock	$3.507B	$3.494B
YoY Change	1.08%	1.53%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$13.74B	$13.07B	$13.07B
YoY Change
Total Liabilities & Shareholders Equity	$50.94B	$49.79B	$49.79B
YoY Change	4.0%	2.71%	2.71%

Cashflow Statement

Concept	2023 Q1	2022 Q4	2022
OPERATING ACTIVITIES
Net Income	$488.7M	$664.0M	-$320.0M
YoY Change	-1024.72%	-23.78%	-113.2%
Depreciation, Depletion And Amortization	$422.1M	$43.79M	$178.8M
YoY Change	10.46%	4.28%	-87.4%
Cash From Operating Activities	$284.2M	$829.2M	$2.709B
YoY Change	-31.5%	27.25%	19.15%
INVESTING ACTIVITIES
Capital Expenditures	$37.18M	$45.43M	$254.7M
YoY Change	-28.08%	-170.44%	75.36%
Acquisitions	$0.00		$79.00M
YoY Change			-84.73%
Other Investing Activities	$1.696M	-$341.4M	$8.294M
YoY Change	-88.06%	142.47%	-116.63%
Cash From Investing Activities	-$108.5M	-$386.9M	-$1.670B
YoY Change	117.17%	88.44%	-43.15%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-$412.2M	-104.3M	-$595.3M
YoY Change	2086.49%	49.76%	-261.0%
NET CHANGE
Cash From Operating Activities	$284.2M	829.2M	$2.709B
Cash From Investing Activities	-$108.5M	-386.9M	-$1.670B
Cash From Financing Activities	-$412.2M	-104.3M	-$595.3M
Net Change In Cash	-$216.7M	338.0M	$340.6M
YoY Change	-166.33%	-10.26%	-201.45%
FREE CASH FLOW
Cash From Operating Activities	$284.2M	$829.2M	$2.709B
Capital Expenditures	$37.18M	$45.43M	$254.7M
Free Cash Flow	$247.0M	$783.7M	$2.455B
YoY Change	-31.99%	9.44%	15.31%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2022	dei	Document Annual Report DocumentAnnualReport	true
CY2022	dei	Document Transition Report DocumentTransitionReport	false
CY2022	dei	Amendment Flag AmendmentFlag	false
CY2022	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2022
CY2022	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2022	dei	Entity Central Index Key EntityCentralIndexKey	0001096343
CY2022	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2022Q4	mkl	Investments Available For Sale Allowance For Credit Loss InvestmentsAvailableForSaleAllowanceForCreditLoss	0	usd
CY2021Q4	mkl	Investments Available For Sale Allowance For Credit Loss InvestmentsAvailableForSaleAllowanceForCreditLoss	0	usd
CY2020Q4	mkl	Investments Available For Sale Allowance For Credit Loss InvestmentsAvailableForSaleAllowanceForCreditLoss	0	usd
CY2022	mkl	Percentage Threshold Of Shareholders Equity Used To Define Concentration Of Investments PercentageThresholdOfShareholdersEquityUsedToDefineConcentrationOfInvestments	0.10
CY2021	mkl	Percentage Threshold Of Shareholders Equity Used To Define Concentration Of Investments PercentageThresholdOfShareholdersEquityUsedToDefineConcentrationOfInvestments	0.10
CY2020	mkl	Percentage Threshold Of Shareholders Equity Used To Define Concentration Of Investments PercentageThresholdOfShareholdersEquityUsedToDefineConcentrationOfInvestments	0.10
CY2022	us-gaap	Fair Value Recurring Basis Unobservable Input Reconciliation Asset Gain Loss Statement Of Income Extensible List FairValueRecurringBasisUnobservableInputReconciliationAssetGainLossStatementOfIncomeExtensibleList	http://www.markelcorp.com/20221231#NetInvestmentGainsLosses
CY2021	us-gaap	Fair Value Recurring Basis Unobservable Input Reconciliation Asset Gain Loss Statement Of Income Extensible List FairValueRecurringBasisUnobservableInputReconciliationAssetGainLossStatementOfIncomeExtensibleList	http://www.markelcorp.com/20221231#NetInvestmentGainsLosses
CY2022	mkl	Fair Value Assets And Liabilities Level1 To Level2 Transfers Amount FairValueAssetsAndLiabilitiesLevel1ToLevel2TransfersAmount	0	usd
CY2021	mkl	Fair Value Assets And Liabilities Level1 To Level2 Transfers Amount FairValueAssetsAndLiabilitiesLevel1ToLevel2TransfersAmount	0	usd
CY2022	mkl	Fair Value Assets And Liabilities Level2 To Level1 Transfers Amount FairValueAssetsAndLiabilitiesLevel2ToLevel1TransfersAmount	0	usd
CY2021	mkl	Fair Value Assets And Liabilities Level2 To Level1 Transfers Amount FairValueAssetsAndLiabilitiesLevel2ToLevel1TransfersAmount	0	usd
CY2021	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	usd
CY2020	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	usd
CY2022	us-gaap	Impairment Of Intangible Assets Excluding Goodwill ImpairmentOfIntangibleAssetsExcludingGoodwill	0	usd
CY2021	us-gaap	Preferred Stock Dividends Per Share Cash Paid PreferredStockDividendsPerShareCashPaid	60.00
CY2021	us-gaap	Impairment Of Intangible Assets Excluding Goodwill ImpairmentOfIntangibleAssetsExcludingGoodwill	0	usd
CY2020	us-gaap	Impairment Of Intangible Assets Excluding Goodwill ImpairmentOfIntangibleAssetsExcludingGoodwill	0	usd
CY2022	us-gaap	Finitelived Intangible Assets Acquired1 FinitelivedIntangibleAssetsAcquired1	0	usd
CY2021Q4	us-gaap	Indefinite Lived Intangible Assets Excluding Goodwill IndefiniteLivedIntangibleAssetsExcludingGoodwill	92400000	usd
CY2022Q4	us-gaap	Operating Lease Right Of Use Asset Statement Of Financial Position Extensible List OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2022#OtherAssets
CY2021Q4	us-gaap	Operating Lease Right Of Use Asset Statement Of Financial Position Extensible List OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2022#OtherAssets
CY2022Q4	us-gaap	Operating Lease Liability Statement Of Financial Position Extensible List OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2022#OtherLiabilities
CY2021Q4	us-gaap	Operating Lease Liability Statement Of Financial Position Extensible List OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2022#OtherLiabilities
CY2022Q4	us-gaap	Operating Lease Liability Statement Of Financial Position Extensible List OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2022#OtherLiabilities
CY2022Q4	mkl	Cumulative Adjustment Lifeand Annuity Benefits CumulativeAdjustmentLifeandAnnuityBenefits	0	usd
CY2022	mkl	Adjustmentto Lifeand Annuity Benefits AdjustmenttoLifeandAnnuityBenefits	-56600000	usd
CY2022	us-gaap	Line Of Credit Facility Initiation Date1 LineOfCreditFacilityInitiationDate1	2019-04-10
CY2022	us-gaap	Line Of Credit Facility Expiration Date1 LineOfCreditFacilityExpirationDate1	2024-04-10
CY2022Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	0	usd
CY2022	us-gaap	Income Tax Examination Year Under Examination IncomeTaxExaminationYearUnderExamination	2017
CY2022	us-gaap	Preferred Stock Dividends Per Share Cash Paid PreferredStockDividendsPerShareCashPaid	60.00
CY2021	us-gaap	Preferred Stock Dividends Per Share Declared PreferredStockDividendsPerShareDeclared	60.00
CY2021	us-gaap	Dividends Preferred Stock DividendsPreferredStock	36000000.0	usd
CY2022	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	36000000.0	usd
CY2021	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	36000000.0	usd
CY2022	dei	Document Type DocumentType	10-K
CY2022	dei	Document Period End Date DocumentPeriodEndDate	2022-12-31
CY2022	dei	Entity File Number EntityFileNumber	001-15811
CY2022	dei	Entity Registrant Name EntityRegistrantName	MARKEL CORPORATION
CY2022	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	VA
CY2022	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	54-1959284
CY2022	dei	Entity Address Address Line1 EntityAddressAddressLine1	4521 Highwoods Parkway
CY2022	dei	Entity Address City Or Town EntityAddressCityOrTown	Glen Allen
CY2022	dei	Entity Address State Or Province EntityAddressStateOrProvince	VA
CY2022	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	23060-6148
CY2022	dei	City Area Code CityAreaCode	804
CY2022	dei	Local Phone Number LocalPhoneNumber	747-0136
CY2022	dei	Security12b Title Security12bTitle	Common Stock, no par value
CY2022	dei	Trading Symbol TradingSymbol	MKL
CY2022	dei	Security Exchange Name SecurityExchangeName	NYSE
CY2022	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2022	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2022	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2022	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2022	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2022	dei	Entity Small Business EntitySmallBusiness	false
CY2022	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2022	dei	Icfr Auditor Attestation Flag IcfrAuditorAttestationFlag	true
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CY2020	mkl	Servicesandotherexpenses Servicesandotherexpenses	1561120000	usd
CY2022	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	178778000	usd
CY2021	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	160539000	usd
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	159315000	usd
CY2022	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	80000000	usd
CY2021	us-gaap	Goodwill And Intangible Asset Impairment GoodwillAndIntangibleAssetImpairment	0	usd
CY2020	us-gaap	Goodwill And Intangible Asset Impairment GoodwillAndIntangibleAssetImpairment	0	usd
CY2022	us-gaap	Costs And Expenses CostsAndExpenses	11768321000	usd
CY2021	us-gaap	Costs And Expenses CostsAndExpenses	9602924000	usd
CY2020	us-gaap	Costs And Expenses CostsAndExpenses	8461182000	usd
CY2022	us-gaap	Operating Income Loss OperatingIncomeLoss	-92986000	usd
CY2021	us-gaap	Operating Income Loss OperatingIncomeLoss	3243501000	usd
CY2020	us-gaap	Operating Income Loss OperatingIncomeLoss	1273884000	usd
CY2021	us-gaap	Interest Expense InterestExpense	183579000	usd
CY2020	us-gaap	Interest Expense InterestExpense	177582000	usd
CY2022	us-gaap	Foreign Currency Transaction Gain Loss Realized ForeignCurrencyTransactionGainLossRealized	140209000	usd
CY2021	us-gaap	Foreign Currency Transaction Gain Loss Realized ForeignCurrencyTransactionGainLossRealized	72271000	usd
CY2020	us-gaap	Foreign Currency Transaction Gain Loss Realized ForeignCurrencyTransactionGainLossRealized	-95853000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	-148839000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	3132193000	usd
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	1000449000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-47636000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	684458000	usd
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	168682000	usd
CY2022	us-gaap	Profit Loss ProfitLoss	-101203000	usd
CY2021	us-gaap	Profit Loss ProfitLoss	2447735000	usd
CY2020	us-gaap	Profit Loss ProfitLoss	831767000	usd
CY2022	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	112920000	usd
CY2021	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	22732000	usd
CY2020	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	15737000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	-214123000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	2425003000	usd
CY2020	us-gaap	Net Income Loss NetIncomeLoss	816030000	usd
CY2022	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	36000000	usd
CY2021	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	36000000	usd
CY2020	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	18400000	usd
CY2022	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-250123000	usd
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	2389003000	usd
CY2020	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	797630000	usd
CY2022	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-1155054000	usd
CY2021	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-348315000	usd
CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	356159000	usd
CY2022	mkl	Reclassification Adjustments For Net Gains Losses Included In Net Income Loss ReclassificationAdjustmentsForNetGainsLossesIncludedInNetIncomeLoss	-44906000	usd
CY2021	mkl	Reclassification Adjustments For Net Gains Losses Included In Net Income Loss ReclassificationAdjustmentsForNetGainsLossesIncludedInNetIncomeLoss	6623000	usd
CY2020	mkl	Reclassification Adjustments For Net Gains Losses Included In Net Income Loss ReclassificationAdjustmentsForNetGainsLossesIncludedInNetIncomeLoss	3386000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-1110148000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-354938000	usd
CY2020	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	352773000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-9259000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-213000	usd
CY2020	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	29847000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-24730000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-8390000	usd
CY2020	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	6998000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-1094677000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-346761000	usd
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	375622000	usd
CY2022	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-1195880000	usd
CY2021	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	2100974000	usd
CY2020	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	1207389000	usd
CY2022	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	112937000	usd
CY2021	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	22730000	usd
CY2020	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	15755000	usd
CY2022	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-1308817000	usd
CY2021	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	2078244000	usd
CY2020	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	1191634000	usd
CY2022	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-23.57
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	176.92
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	55.67
CY2022	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-23.57
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	176.51
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	55.63
CY2022	us-gaap	Profit Loss ProfitLoss	-101203000	usd
CY2021	us-gaap	Profit Loss ProfitLoss	2447735000	usd
CY2020	us-gaap	Profit Loss ProfitLoss	831767000	usd
CY2022	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	281752000	usd
CY2021	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	-453905000	usd
CY2020	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	2733000	usd
CY2022	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	366954000	usd
CY2021	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	336393000	usd
CY2020	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	307069000	usd
CY2022	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	-1595733000	usd
CY2021	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	1978534000	usd
CY2020	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	617979000	usd
CY2022	us-gaap	Foreign Currency Transaction Gain Loss Realized ForeignCurrencyTransactionGainLossRealized	140209000	usd
CY2021	us-gaap	Foreign Currency Transaction Gain Loss Realized ForeignCurrencyTransactionGainLossRealized	72271000	usd
CY2020	us-gaap	Foreign Currency Transaction Gain Loss Realized ForeignCurrencyTransactionGainLossRealized	-95853000	usd
CY2022	us-gaap	Gain Loss On Sale Of Business GainLossOnSaleOfBusiness	225832000	usd
CY2021	us-gaap	Gain Loss On Sale Of Business GainLossOnSaleOfBusiness	22085000	usd
CY2020	us-gaap	Gain Loss On Sale Of Business GainLossOnSaleOfBusiness	0	usd
CY2022	us-gaap	Goodwill And Intangible Asset Impairment GoodwillAndIntangibleAssetImpairment	80000000	usd
CY2021	us-gaap	Goodwill And Intangible Asset Impairment GoodwillAndIntangibleAssetImpairment	0	usd
CY2020	us-gaap	Goodwill And Intangible Asset Impairment GoodwillAndIntangibleAssetImpairment	0	usd
CY2022	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	653261000	usd
CY2021	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	372491000	usd
CY2020	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	28174000	usd
CY2022	us-gaap	Increase Decrease In Reinsurance Recoverable IncreaseDecreaseInReinsuranceRecoverable	1168483000	usd
CY2021	us-gaap	Increase Decrease In Reinsurance Recoverable IncreaseDecreaseInReinsuranceRecoverable	1312258000	usd
CY2020	us-gaap	Increase Decrease In Reinsurance Recoverable IncreaseDecreaseInReinsuranceRecoverable	549654000	usd
CY2022	us-gaap	Increase Decrease In Deferred Policy Acquisition Costs IncreaseDecreaseInDeferredPolicyAcquisitionCosts	140630000	usd
CY2021	us-gaap	Increase Decrease In Deferred Policy Acquisition Costs IncreaseDecreaseInDeferredPolicyAcquisitionCosts	139609000	usd
CY2020	us-gaap	Increase Decrease In Deferred Policy Acquisition Costs IncreaseDecreaseInDeferredPolicyAcquisitionCosts	61569000	usd
CY2022	us-gaap	Increase Decrease In Prepaid Reinsurance Premiums IncreaseDecreaseInPrepaidReinsurancePremiums	271292000	usd
CY2021	us-gaap	Increase Decrease In Prepaid Reinsurance Premiums IncreaseDecreaseInPrepaidReinsurancePremiums	347982000	usd
CY2020	us-gaap	Increase Decrease In Prepaid Reinsurance Premiums IncreaseDecreaseInPrepaidReinsurancePremiums	34480000	usd
CY2022	us-gaap	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve	2383268000	usd
CY2021	us-gaap	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve	2042486000	usd
CY2020	us-gaap	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve	1383430000	usd
CY2022	us-gaap	Increase Decrease In Life Insurance Liabilities IncreaseDecreaseInLifeInsuranceLiabilities	-47419000	usd
CY2021	us-gaap	Increase Decrease In Life Insurance Liabilities IncreaseDecreaseInLifeInsuranceLiabilities	-54591000	usd
CY2020	us-gaap	Increase Decrease In Life Insurance Liabilities IncreaseDecreaseInLifeInsuranceLiabilities	-44651000	usd
CY2022	us-gaap	Increase Decrease In Unearned Premiums IncreaseDecreaseInUnearnedPremiums	886393000	usd
CY2021	us-gaap	Increase Decrease In Unearned Premiums IncreaseDecreaseInUnearnedPremiums	970246000	usd
CY2020	us-gaap	Increase Decrease In Unearned Premiums IncreaseDecreaseInUnearnedPremiums	354679000	usd
CY2022	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	210810000	usd
CY2021	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	131559000	usd
CY2020	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	76586000	usd
CY2022	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-216365000	usd
CY2021	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-191564000	usd
CY2020	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-27443000	usd
CY2022	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	2709442000	usd
CY2021	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	2274067000	usd
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	1737587000	usd
CY2022	us-gaap	Proceeds From Sale And Maturity Of Available For Sale Securities ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities	1152335000	usd
CY2021	us-gaap	Proceeds From Sale And Maturity Of Available For Sale Securities ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities	708111000	usd
CY2020	us-gaap	Proceeds From Sale And Maturity Of Available For Sale Securities ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities	862333000	usd
CY2022	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	2112066000	usd
CY2021	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	3165323000	usd
CY2020	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	1129781000	usd
CY2022	us-gaap	Proceeds From Sale Of Equity Securities Fv Ni ProceedsFromSaleOfEquitySecuritiesFvNi	242010000	usd
CY2021	us-gaap	Proceeds From Sale Of Equity Securities Fv Ni ProceedsFromSaleOfEquitySecuritiesFvNi	200570000	usd
CY2020	us-gaap	Proceeds From Sale Of Equity Securities Fv Ni ProceedsFromSaleOfEquitySecuritiesFvNi	1360090000	usd
CY2022	us-gaap	Payments To Acquire Equity Securities Fv Ni PaymentsToAcquireEquitySecuritiesFvNi	442991000	usd
CY2021	us-gaap	Payments To Acquire Equity Securities Fv Ni PaymentsToAcquireEquitySecuritiesFvNi	255436000	usd
CY2020	us-gaap	Payments To Acquire Equity Securities Fv Ni PaymentsToAcquireEquitySecuritiesFvNi	192437000	usd
CY2022	us-gaap	Payments For Proceeds From Short Term Investments PaymentsForProceedsFromShortTermInvestments	846019000	usd
CY2021	us-gaap	Payments For Proceeds From Short Term Investments PaymentsForProceedsFromShortTermInvestments	-228955000	usd
CY2020	us-gaap	Payments For Proceeds From Short Term Investments PaymentsForProceedsFromShortTermInvestments	829457000	usd
CY2022	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	254712000	usd
CY2021	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	145249000	usd
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	101301000	usd
CY2022	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	79000000	usd
CY2021	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	517439000	usd
CY2020	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	554127000	usd
CY2022	mkl	Consolidation Of Markel Cat Co Re Net ConsolidationOfMarkelCATCoReNet	629955000	usd
CY2021	mkl	Consolidation Of Markel Cat Co Re Net ConsolidationOfMarkelCATCoReNet	0	usd
CY2020	mkl	Consolidation Of Markel Cat Co Re Net ConsolidationOfMarkelCATCoReNet	0	usd
CY2022	mkl	Distributions To Markel Cat Co Re Noncontrolling Interests For Buy Out Transaction DistributionsToMarkelCATCoReNoncontrollingInterestsForBuyOutTransaction	169380000	usd
CY2021	mkl	Distributions To Markel Cat Co Re Noncontrolling Interests For Buy Out Transaction DistributionsToMarkelCATCoReNoncontrollingInterestsForBuyOutTransaction	0	usd
CY2020	mkl	Distributions To Markel Cat Co Re Noncontrolling Interests For Buy Out Transaction DistributionsToMarkelCATCoReNoncontrollingInterestsForBuyOutTransaction	0	usd
CY2022	us-gaap	Proceeds From Divestiture Of Businesses Net Of Cash Divested ProceedsFromDivestitureOfBusinessesNetOfCashDivested	201370000	usd
CY2021	us-gaap	Proceeds From Divestiture Of Businesses Net Of Cash Divested ProceedsFromDivestitureOfBusinessesNetOfCashDivested	40720000	usd
CY2020	us-gaap	Proceeds From Divestiture Of Businesses Net Of Cash Divested ProceedsFromDivestitureOfBusinessesNetOfCashDivested	0	usd
CY2022	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	8294000	usd
CY2021	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-32711000	usd
CY2020	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	72932000	usd
CY2022	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-1670204000	usd
CY2021	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-2937802000	usd
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-511748000	usd
CY2022	us-gaap	Proceeds From Issuance Of Debt ProceedsFromIssuanceOfDebt	1034052000	usd
CY2021	us-gaap	Proceeds From Issuance Of Debt ProceedsFromIssuanceOfDebt	1198505000	usd
CY2020	us-gaap	Proceeds From Issuance Of Debt ProceedsFromIssuanceOfDebt	223183000	usd
CY2022	us-gaap	Repayments Of Debt RepaymentsOfDebt	1255005000	usd
CY2021	us-gaap	Repayments Of Debt RepaymentsOfDebt	486730000	usd
CY2020	us-gaap	Repayments Of Debt RepaymentsOfDebt	275996000	usd
CY2022	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	290796000	usd
CY2021	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	206518000	usd
CY2020	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	26832000	usd
CY2022	us-gaap	Proceeds From Issuance Of Preferred Stock And Preference Stock ProceedsFromIssuanceOfPreferredStockAndPreferenceStock	0	usd
CY2021	us-gaap	Proceeds From Issuance Of Preferred Stock And Preference Stock ProceedsFromIssuanceOfPreferredStockAndPreferenceStock	0	usd
CY2020	us-gaap	Proceeds From Issuance Of Preferred Stock And Preference Stock ProceedsFromIssuanceOfPreferredStockAndPreferenceStock	591891000	usd
CY2022	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	36000000	usd
CY2021	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	36000000	usd
CY2020	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	18400000	usd
CY2022	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-47562000	usd
CY2021	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-99490000	usd
CY2020	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-59290000	usd
CY2022	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-595311000	usd
CY2021	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	369767000	usd
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	434556000	usd
CY2022	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-103361000	usd
CY2021	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-41734000	usd
CY2020	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	55901000	usd
CY2022	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	340566000	usd
CY2021	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-335702000	usd
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	1716296000	usd
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	4880947000	usd
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	5216649000	usd
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	3500353000	usd
CY2022Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	5221513000	usd
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	4880947000	usd
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	5216649000	usd
CY2022	us-gaap	Use Of Estimates UseOfEstimates	Use of Estimates. The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities. Management periodically reviews its estimates and assumptions. Quarterly reviews include evaluating the adequacy of reserves for unpaid losses and loss adjustment expenses and contingencies. Estimates and assumptions for goodwill and intangible assets are reviewed in conjunction with an acquisition, and goodwill and indefinite-lived intangible assets are reassessed at least annually for impairment. Actual results may differ materially from the estimates and assumptions used in preparing the consolidated financial statements.
CY2022	mkl	Deferred Policy Acquisition Cost Amortization Period DeferredPolicyAcquisitionCostAmortizationPeriod	P1Y
CY2022Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	1200000000	usd
CY2021Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	1100000000	usd
CY2022Q4	us-gaap	Inventory Net InventoryNet	639600000	usd
CY2021Q4	us-gaap	Inventory Net InventoryNet	529300000	usd
CY2022	mkl	Tax Benefit Greater Than Fifty Percent TaxBenefitGreaterThanFiftyPercent	0.50
CY2022	mkl	Revenue Recognition Period Insurance Premiums RevenueRecognitionPeriodInsurancePremiums	P1Y
CY2021Q1	mkl	Impact To Accumulated Other Comprehensive Income Net Of Taxes As A Result Of Changing The Discount Rate Assumption Under Asu201812 ImpactToAccumulatedOtherComprehensiveIncomeNetOfTaxesAsAResultOfChangingTheDiscountRateAssumptionUnderASU201812	-15300000	usd
CY2023Q1	mkl	Cumulative Impact To Accumulated Other Comprehensive Income Net Of Taxes As A Result Of Adopting Asu201812 CumulativeImpactToAccumulatedOtherComprehensiveIncomeNetOfTaxesAsAResultOfAdoptingASU201812	89600000	usd
CY2022	us-gaap	Premiums Written Gross PremiumsWrittenGross	13201682000	usd
CY2022	us-gaap	Premiums Written Net PremiumsWrittenNet	8203390000	usd
CY2022	us-gaap	Premiums Earned Net PremiumsEarnedNet	7587792000	usd
CY2022	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	4613035000	usd
CY2022	mkl	Supplemental Info For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense Including Amounts Related To Liabilities Not Included In Unpaid Losses And Lae SupplementalInfoForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpenseIncludingAmountsRelatedToLiabilitiesNotIncludedInUnpaidLossesAndLAE	-167446000	usd
CY2022	us-gaap	Deferred Policy Acquisition Cost Amortization Expense DeferredPolicyAcquisitionCostAmortizationExpense	1655106000	usd
CY2022	us-gaap	Other Underwriting Expense OtherUnderwritingExpense	860477000	usd
CY2022	mkl	Underwriting Profit Loss UnderwritingProfitLoss	626620000	usd
CY2022	us-gaap	Net Investment Income NetInvestmentIncome	446755000	usd
CY2022	mkl	Net Investment Gains Losses NetInvestmentGainsLosses	-1595733000	usd
CY2022	mkl	Products Revenues ProductsRevenues	2427096000	usd
CY2022	mkl	Servicesandotherrevenues Servicesandotherrevenues	2809425000	usd
CY2022	mkl	Productsexpenses Productsexpenses	2241736000	usd
CY2022	mkl	Servicesandotherexpenses Servicesandotherexpenses	2306635000	usd
CY2022	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	178778000	usd
CY2022	us-gaap	Goodwill And Intangible Asset Impairment GoodwillAndIntangibleAssetImpairment	80000000	usd
CY2022	mkl	Total Profit Loss TotalProfitLoss	-92986000	usd
CY2022	us-gaap	Interest Expense InterestExpense	196062000	usd
CY2022	us-gaap	Foreign Currency Transaction Gain Loss Realized ForeignCurrencyTransactionGainLossRealized	140209000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	-148839000	usd
CY2021	us-gaap	Premiums Written Gross PremiumsWrittenGross	11438682000	usd
CY2021	us-gaap	Premiums Written Net PremiumsWrittenNet	7119731000	usd
CY2021	us-gaap	Premiums Earned Net PremiumsEarnedNet	6503029000	usd
CY2021	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	4061000000	usd
CY2021	mkl	Supplemental Info For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense Including Amounts Related To Liabilities Not Included In Unpaid Losses And Lae SupplementalInfoForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpenseIncludingAmountsRelatedToLiabilitiesNotIncludedInUnpaidLossesAndLAE	-479795000	usd
CY2021	us-gaap	Deferred Policy Acquisition Cost Amortization Expense DeferredPolicyAcquisitionCostAmortizationExpense	1419266000	usd
CY2021	us-gaap	Other Underwriting Expense OtherUnderwritingExpense	874473000	usd
CY2021	mkl	Underwriting Profit Loss UnderwritingProfitLoss	628085000	usd
CY2021	us-gaap	Net Investment Income NetInvestmentIncome	367417000	usd
CY2021	mkl	Net Investment Gains Losses NetInvestmentGainsLosses	1978534000	usd
CY2021	mkl	Products Revenues ProductsRevenues	1712120000	usd
CY2021	mkl	Servicesandotherrevenues Servicesandotherrevenues	2285325000	usd
CY2021	mkl	Productsexpenses Productsexpenses	1544506000	usd
CY2021	mkl	Servicesandotherexpenses Servicesandotherexpenses	2022935000	usd
CY2021	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	160539000	usd
CY2021	mkl	Total Profit Loss TotalProfitLoss	3243501000	usd
CY2021	us-gaap	Interest Expense InterestExpense	183579000	usd
CY2021	us-gaap	Foreign Currency Transaction Gain Loss Realized ForeignCurrencyTransactionGainLossRealized	72271000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	3132193000	usd
CY2020	us-gaap	Premiums Written Gross PremiumsWrittenGross	9266665000	usd
CY2020	us-gaap	Premiums Written Net PremiumsWrittenNet	5932238000	usd
CY2020	us-gaap	Premiums Earned Net PremiumsEarnedNet	5612205000	usd
CY2020	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	4073325000	usd
CY2020	mkl	Supplemental Info For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense Including Amounts Related To Liabilities Not Included In Unpaid Losses And Lae SupplementalInfoForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpenseIncludingAmountsRelatedToLiabilitiesNotIncludedInUnpaidLossesAndLAE	-606364000	usd
CY2020	us-gaap	Deferred Policy Acquisition Cost Amortization Expense DeferredPolicyAcquisitionCostAmortizationExpense	1229161000	usd
CY2020	us-gaap	Other Underwriting Expense OtherUnderwritingExpense	788466000	usd
CY2020	mkl	Underwriting Profit Loss UnderwritingProfitLoss	127617000	usd
CY2020	us-gaap	Net Investment Income NetInvestmentIncome	375826000	usd
CY2020	mkl	Net Investment Gains Losses NetInvestmentGainsLosses	617979000	usd
CY2020	mkl	Products Revenues ProductsRevenues	1439515000	usd
CY2020	mkl	Servicesandotherrevenues Servicesandotherrevenues	1689541000	usd
CY2020	mkl	Productsexpenses Productsexpenses	1256159000	usd
CY2020	mkl	Servicesandotherexpenses Servicesandotherexpenses	1561120000	usd
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	159315000	usd
CY2020	mkl	Total Profit Loss TotalProfitLoss	1273884000	usd
CY2020	us-gaap	Interest Expense InterestExpense	177582000	usd
CY2020	us-gaap	Foreign Currency Transaction Gain Loss Realized ForeignCurrencyTransactionGainLossRealized	-95853000	usd
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	1000449000	usd
CY2022	us-gaap	Premiums Earned Net PremiumsEarnedNet	7587792000	usd
CY2021	us-gaap	Premiums Earned Net PremiumsEarnedNet	6503029000	usd
CY2020	us-gaap	Premiums Earned Net PremiumsEarnedNet	5612205000	usd
CY2022Q4	us-gaap	Assets Assets	49791259000	usd
CY2021Q4	us-gaap	Assets Assets	48477096000	usd
CY2022Q4	us-gaap	Deferred Policy Acquisition Costs DeferredPolicyAcquisitionCosts	925483000	usd
CY2022Q4	us-gaap	Unearned Premiums UnearnedPremiums	6220748000	usd
CY2022Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	20947898000	usd
CY2021Q4	us-gaap	Deferred Policy Acquisition Costs DeferredPolicyAcquisitionCosts	794145000	usd
CY2021Q4	us-gaap	Unearned Premiums UnearnedPremiums	5383619000	usd
CY2021Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	18178894000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	12805887000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	12805887000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	13100000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	962152000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	11856835000	usd
CY2022Q4	mkl	Shortterm Investments Availablefor Sale Amortized Cost Basis ShorttermInvestmentsAvailableforSaleAmortizedCostBasis	2663560000	usd
CY2022Q4	mkl	Shortterm Investments Availablefor Sale Accumulated Gross Unrealized Gain Before Tax ShorttermInvestmentsAvailableforSaleAccumulatedGrossUnrealizedGainBeforeTax	5760000	usd
CY2022Q4	mkl	Shortterm Investments Availablefor Sale Accumulated Gross Unrealized Loss Before Tax ShorttermInvestmentsAvailableforSaleAccumulatedGrossUnrealizedLossBeforeTax	58000	usd
CY2022Q4	mkl	Shortterm Investments Availablefor Sale ShorttermInvestmentsAvailableforSale	2669262000	usd
CY2022Q4	mkl	Investments Availablefor Sale Amortized Cost Basis InvestmentsAvailableforSaleAmortizedCostBasis	15469447000	usd
CY2022Q4	mkl	Investments Availablefor Sale Accumulated Gross Unrealized Gain Before Tax InvestmentsAvailableforSaleAccumulatedGrossUnrealizedGainBeforeTax	18860000	usd
CY2022Q4	mkl	Investments Availablefor Sale Accumulated Gross Unrealized Loss Before Tax InvestmentsAvailableforSaleAccumulatedGrossUnrealizedLossBeforeTax	962210000	usd
CY2022Q4	mkl	Investments Availablefor Sale InvestmentsAvailableforSale	14526097000	usd
CY2021Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	12061467000	usd
CY2021Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	12061467000	usd
CY2021Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	583691000	usd
CY2021Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	57853000	usd
CY2021Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	12587305000	usd
CY2021Q4	mkl	Shortterm Investments Availablefor Sale Amortized Cost Basis ShorttermInvestmentsAvailableforSaleAmortizedCostBasis	1805300000	usd
CY2021Q4	mkl	Shortterm Investments Availablefor Sale Accumulated Gross Unrealized Gain Before Tax ShorttermInvestmentsAvailableforSaleAccumulatedGrossUnrealizedGainBeforeTax	28000	usd
CY2021Q4	mkl	Shortterm Investments Availablefor Sale Accumulated Gross Unrealized Loss Before Tax ShorttermInvestmentsAvailableforSaleAccumulatedGrossUnrealizedLossBeforeTax	5340000	usd
CY2021Q4	mkl	Shortterm Investments Availablefor Sale ShorttermInvestmentsAvailableforSale	1799988000	usd
CY2021Q4	mkl	Investments Availablefor Sale Amortized Cost Basis InvestmentsAvailableforSaleAmortizedCostBasis	13866767000	usd
CY2021Q4	mkl	Investments Availablefor Sale Accumulated Gross Unrealized Gain Before Tax InvestmentsAvailableforSaleAccumulatedGrossUnrealizedGainBeforeTax	583719000	usd
CY2021Q4	mkl	Investments Availablefor Sale Accumulated Gross Unrealized Loss Before Tax InvestmentsAvailableforSaleAccumulatedGrossUnrealizedLossBeforeTax	63193000	usd
CY2021Q4	mkl	Investments Availablefor Sale InvestmentsAvailableforSale	14387293000	usd
CY2022Q4	mkl	Shortterm Investments Availableforsale Continuous Unrealized Loss Position Lessthan12 Months ShorttermInvestmentsAvailableforsaleContinuousUnrealizedLossPositionLessthan12Months	774480000	usd
CY2022Q4	mkl	Shortterm Investments Availableforsale Continuous Unrealized Loss Position Lessthan12 Months Accumulated Loss ShorttermInvestmentsAvailableforsaleContinuousUnrealizedLossPositionLessthan12MonthsAccumulatedLoss	-58000	usd
CY2022Q4	mkl	Shortterm Investments Availableforsale Continuous Unrealized Loss Position12 Monthsor Longer ShorttermInvestmentsAvailableforsaleContinuousUnrealizedLossPosition12MonthsorLonger	0	usd
CY2022Q4	mkl	Shortterm Investments Availableforsale Continuous Unrealized Loss Position12 Monthsor Longer Accumulated Loss ShorttermInvestmentsAvailableforsaleContinuousUnrealizedLossPosition12MonthsorLongerAccumulatedLoss	0	usd
CY2022Q4	mkl	Shortterm Investments Availableforsale Unrealized Loss Position Total ShorttermInvestmentsAvailableforsaleUnrealizedLossPositionTotal	774480000	usd
CY2022Q4	mkl	Shortterm Investments Availableforsale Unrealized Loss Position Accumulated Loss ShorttermInvestmentsAvailableforsaleUnrealizedLossPositionAccumulatedLoss	-58000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	7924623000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	568299000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	3356273000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	393911000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	11280896000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	962210000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Number Of Positions DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions	1400	securities
CY2022Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	11300000000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	962200000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Number Of Positions DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions	1400	securities
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Number Of Positions DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions	246	securities
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	3400000000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	393900000	usd
CY2021Q4	mkl	Shortterm Investments Availableforsale Continuous Unrealized Loss Position Lessthan12 Months ShorttermInvestmentsAvailableforsaleContinuousUnrealizedLossPositionLessthan12Months	228870000	usd
CY2021Q4	mkl	Shortterm Investments Availableforsale Continuous Unrealized Loss Position Lessthan12 Months Accumulated Loss ShorttermInvestmentsAvailableforsaleContinuousUnrealizedLossPositionLessthan12MonthsAccumulatedLoss	-5340000	usd
CY2021Q4	mkl	Shortterm Investments Availableforsale Continuous Unrealized Loss Position12 Monthsor Longer ShorttermInvestmentsAvailableforsaleContinuousUnrealizedLossPosition12MonthsorLonger	0	usd
CY2021Q4	mkl	Shortterm Investments Availableforsale Continuous Unrealized Loss Position12 Monthsor Longer Accumulated Loss ShorttermInvestmentsAvailableforsaleContinuousUnrealizedLossPosition12MonthsorLongerAccumulatedLoss	0	usd
CY2021Q4	mkl	Shortterm Investments Availableforsale Unrealized Loss Position Total ShorttermInvestmentsAvailableforsaleUnrealizedLossPositionTotal	228870000	usd
CY2021Q4	mkl	Shortterm Investments Availableforsale Unrealized Loss Position Accumulated Loss ShorttermInvestmentsAvailableforsaleUnrealizedLossPositionAccumulatedLoss	-5340000	usd
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	4115294000	usd
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	57145000	usd
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	169794000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	3708752000	usd
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	6048000	usd
CY2021Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	4285088000	usd
CY2021Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	63193000	usd
CY2021Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Number Of Positions DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions	277	securities
CY2021Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	4300000000	usd
CY2021Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	63200000	usd
CY2021Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Number Of Positions DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions	277	securities
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Number Of Positions DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions	13	securities
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	169800000	usd
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	6000000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	1363418000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	1337550000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	3926756000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	3115913000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	2787686000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	1734795000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	1553966000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	10140882000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate	9387954000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	12805887000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	11856835000	usd
CY2022	mkl	Estimated Average Duration Of Fixed Maturities EstimatedAverageDurationOfFixedMaturities	P3Y10M24D
CY2022	us-gaap	Investment Income Dividend InvestmentIncomeDividend	107213000	usd
CY2021	us-gaap	Investment Income Dividend InvestmentIncomeDividend	98099000	usd
CY2020	us-gaap	Investment Income Dividend InvestmentIncomeDividend	89303000	usd
CY2022	us-gaap	Investment Income Interest And Dividend InvestmentIncomeInterestAndDividend	464013000	usd
CY2021	us-gaap	Investment Income Interest And Dividend InvestmentIncomeInterestAndDividend	384419000	usd
CY2020	us-gaap	Investment Income Interest And Dividend InvestmentIncomeInterestAndDividend	392045000	usd
CY2022	us-gaap	Investment Income Investment Expense InvestmentIncomeInvestmentExpense	17258000	usd
CY2021	us-gaap	Investment Income Investment Expense InvestmentIncomeInvestmentExpense	17002000	usd
CY2020	us-gaap	Investment Income Investment Expense InvestmentIncomeInvestmentExpense	16219000	usd
CY2022	us-gaap	Net Investment Income NetInvestmentIncome	446755000	usd
CY2021	us-gaap	Net Investment Income NetInvestmentIncome	367417000	usd
CY2020	us-gaap	Net Investment Income NetInvestmentIncome	375826000	usd
CY2022	mkl	Net Realized Investment Gains Losses NetRealizedInvestmentGainsLosses	-40983000	usd
CY2021	mkl	Net Realized Investment Gains Losses NetRealizedInvestmentGainsLosses	37908000	usd
CY2020	mkl	Net Realized Investment Gains Losses NetRealizedInvestmentGainsLosses	14780000	usd
CY2022	us-gaap	Equity Securities Fv Ni Realized Gain Loss EquitySecuritiesFvNiRealizedGainLoss	-14884000	usd
CY2021	us-gaap	Equity Securities Fv Ni Realized Gain Loss EquitySecuritiesFvNiRealizedGainLoss	25902000	usd
CY2020	us-gaap	Equity Securities Fv Ni Realized Gain Loss EquitySecuritiesFvNiRealizedGainLoss	-470008000	usd
CY2022	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	-1539866000	usd
CY2021	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	1914724000	usd
CY2020	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	1073207000	usd
CY2022	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	-1554750000	usd
CY2021	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	1940626000	usd
CY2020	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	603199000	usd
CY2022	mkl	Net Investment Gains Losses NetInvestmentGainsLosses	-1595733000	usd
CY2021	mkl	Net Investment Gains Losses NetInvestmentGainsLosses	1978534000	usd
CY2020	mkl	Net Investment Gains Losses NetInvestmentGainsLosses	617979000	usd
CY2022	mkl	Other Comprehensive Income Securities Availablefor Sale Lifeand Annuity Benefits Reserves Adjustmentbefore Tax OtherComprehensiveIncomeSecuritiesAvailableforSaleLifeandAnnuityBenefitsReservesAdjustmentbeforeTax	56560000	usd
CY2021	mkl	Other Comprehensive Income Securities Availablefor Sale Lifeand Annuity Benefits Reserves Adjustmentbefore Tax OtherComprehensiveIncomeSecuritiesAvailableforSaleLifeandAnnuityBenefitsReservesAdjustmentbeforeTax	62988000	usd
CY2020	mkl	Other Comprehensive Income Securities Availablefor Sale Lifeand Annuity Benefits Reserves Adjustmentbefore Tax OtherComprehensiveIncomeSecuritiesAvailableforSaleLifeandAnnuityBenefitsReservesAdjustmentbeforeTax	-68158000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	-1407316000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	-450096000	usd
CY2020	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	442089000	usd
CY2022Q4	mkl	Restricted Investments Available For Sale RestrictedInvestmentsAvailableForSale	4160842000	usd
CY2021Q4	mkl	Restricted Investments Available For Sale RestrictedInvestmentsAvailableForSale	4403414000	usd
CY2022Q4	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	1084081000	usd
CY2021Q4	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	902457000	usd
CY2022Q4	us-gaap	Restricted Cash And Investments RestrictedCashAndInvestments	5244923000	usd
CY2021Q4	us-gaap	Restricted Cash And Investments RestrictedCashAndInvestments	5305871000	usd
CY2022Q4	us-gaap	Restricted Cash And Investments RestrictedCashAndInvestments	5244923000	usd
CY2021Q4	us-gaap	Restricted Cash And Investments RestrictedCashAndInvestments	5305871000	usd
CY2022	mkl	Percentage Threshold Of Shareholders Equity Used To Define Concentration Of Investments PercentageThresholdOfShareholdersEquityUsedToDefineConcentrationOfInvestments	0.10
CY2021Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	56472000	usd
CY2020Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	58493000	usd
CY2022	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchases FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases	0	usd
CY2021	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchases FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases	18900000	usd
CY2022	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Sales FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales	56335000	usd
CY2021	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Sales FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales	15015000	usd
CY2022	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1	762000	usd
CY2021	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1	-5906000	usd
CY2022Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	899000	usd
CY2021Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	56472000	usd
CY2022Q4	us-gaap	Equity Method Investments EquityMethodInvestments	494000000	usd
CY2021Q4	us-gaap	Equity Method Investments EquityMethodInvestments	459700000	usd
CY2022	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-22900000	usd
CY2021	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	15000000	usd
CY2020	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-3400000	usd
CY2022Q4	us-gaap	Premiums Receivable Gross PremiumsReceivableGross	2176295000	usd
CY2021Q4	us-gaap	Premiums Receivable Gross PremiumsReceivableGross	1740864000	usd
CY2022Q4	mkl	Other Insurance Receivables Gross OtherInsuranceReceivablesGross	83728000	usd
CY2021Q4	mkl	Other Insurance Receivables Gross OtherInsuranceReceivablesGross	133350000	usd
CY2022Q4	mkl	Markel Ventures Accounts Receivable Gross MarkelVenturesAccountsReceivableGross	645189000	usd
CY2021Q4	mkl	Markel Ventures Accounts Receivable Gross MarkelVenturesAccountsReceivableGross	510382000	usd
CY2022Q4	us-gaap	Other Receivables OtherReceivables	77961000	usd
CY2021Q4	us-gaap	Other Receivables OtherReceivables	50379000	usd
CY2022Q4	us-gaap	Accounts Receivable Gross AccountsReceivableGross	2983173000	usd
CY2021Q4	us-gaap	Accounts Receivable Gross AccountsReceivableGross	2434975000	usd
CY2022Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	22117000	usd
CY2021Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	21037000	usd
CY2022Q4	us-gaap	Premiums And Other Receivables Net PremiumsAndOtherReceivablesNet	2961056000	usd
CY2021Q4	us-gaap	Premiums And Other Receivables Net PremiumsAndOtherReceivablesNet	2413938000	usd
CY2020Q4	us-gaap	Goodwill Goodwill	2604624000	usd
CY2021	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	293838000	usd
CY2021Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	1822486000	usd
CY2022	mkl	Intangible Assets Acquired During Period IntangibleAssetsAcquiredDuringPeriod	21614000	usd
CY2021	us-gaap	Goodwill Foreign Currency Translation Gain Loss GoodwillForeignCurrencyTranslationGainLoss	678000	usd
CY2021Q4	us-gaap	Goodwill Goodwill	2899140000	usd
CY2022	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	41905000	usd
CY2022	mkl	Goodwill Disposed Of During Period GoodwillDisposedOfDuringPeriod	-132455000	usd
CY2022	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	80000000	usd
CY2022	mkl	Goodwill Adjustments To Preliminary Purchase Price Allocation GoodwillAdjustmentsToPreliminaryPurchasePriceAllocation	-83358000	usd
CY2022	us-gaap	Goodwill Foreign Currency Translation Gain Loss GoodwillForeignCurrencyTranslationGainLoss	-6394000	usd
CY2022Q4	us-gaap	Goodwill Goodwill	2638838000	usd
CY2022Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	190600000	usd
CY2021Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	110600000	usd
CY2022	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	80000000	usd
CY2020Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	1782718000	usd
CY2021	mkl	Intangible Assets Acquired During Period IntangibleAssetsAcquiredDuringPeriod	203879000	usd
CY2021	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	160539000	usd
CY2021	us-gaap	Finite Lived Intangible Assets Translation And Purchase Accounting Adjustments FiniteLivedIntangibleAssetsTranslationAndPurchaseAccountingAdjustments	-3572000	usd
CY2022	mkl	Lease Of Facilities And Furniture Maximum Duration LeaseOfFacilitiesAndFurnitureMaximumDuration	P20Y
CY2022	mkl	Intangible Assets Disposed During Period IntangibleAssetsDisposedDuringPeriod	-2716000	usd
CY2022	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	178778000	usd
CY2022	mkl	Intangible Assets Adjustments To Preliminary Purchase Price Allocation IntangibleAssetsAdjustmentsToPreliminaryPurchasePriceAllocation	86773000	usd
CY2022	us-gaap	Finite Lived Intangible Assets Translation And Purchase Accounting Adjustments FiniteLivedIntangibleAssetsTranslationAndPurchaseAccountingAdjustments	-1915000	usd
CY2022Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	1747464000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	174000000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	172100000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	165600000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	157500000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	149900000	usd
CY2022Q4	us-gaap	Indefinite Lived Intangible Assets Excluding Goodwill IndefiniteLivedIntangibleAssetsExcludingGoodwill	92400000	usd
CY2022Q4	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	2836774000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	1089310000	usd
CY2021Q4	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	2739602000	usd
CY2021Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	917116000	usd
CY2022	us-gaap	Operating Lease Expense OperatingLeaseExpense	126300000	usd
CY2021	us-gaap	Operating Lease Expense OperatingLeaseExpense	115400000	usd
CY2020	us-gaap	Operating Lease Expense OperatingLeaseExpense	94400000	usd
CY2022Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	526704000	usd
CY2021Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	533702000	usd
CY2022Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	554394000	usd
CY2021Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	571337000	usd
CY2022Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P11Y8M12D
CY2021Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P10Y9M18D
CY2022Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.031
CY2021Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.030
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	100887000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	85030000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	71474000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	60729000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	51702000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	291290000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	661112000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	106718000	usd
CY2022Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	554394000	usd
CY2022	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	5236521000	usd
CY2021	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3997445000	usd
CY2020	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3129056000	usd
CY2022	us-gaap	Schedule Of Liability For Unpaid Claims And Claims Adjustment Expense ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense	The following table presents a reconciliation of consolidated beginning and ending reserves for losses and loss adjustment expenses.<table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"/><td style="width:59.224%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.731%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.389%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.731%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.389%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.736%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="15" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Years Ended December 31,</span></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-style:italic;font-weight:400;line-height:100%;text-decoration:underline">(dollars in thousands)</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2022</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">2021</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">2020</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Gross reserves for losses and loss adjustment expenses, beginning of year</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">18,178,894</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">16,222,376 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">14,728,676 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Reinsurance recoverables on unpaid losses, beginning of year</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">6,876,317</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5,736,659 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5,253,415 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net reserves for losses and loss adjustment expenses, beginning of year</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">11,302,577</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">10,485,717 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">9,475,261 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 19pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Effect of foreign currency rate changes on beginning of year balance</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">(160,622)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(54,736)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">68,368 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Effect of adoption of ASC 326, </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:100%">Financial Instruments—Credit Losses</span></div></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">—</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">— </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">3,849 </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Adjusted net reserves for losses and loss adjustment expenses, beginning of year</span></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">11,141,955</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">10,430,981 </span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">9,547,478 </span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Incurred losses and loss adjustment expenses:</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 19pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Current accident year</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">4,613,035</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,061,000 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,073,325 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 19pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Prior accident years</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">(167,446)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(478,930)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(606,414)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 19pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total incurred losses and loss adjustment expenses</span></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">4,445,589</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">3,582,070 </span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">3,466,911 </span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Payments:</span></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 19pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Current accident year</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">580,537</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">637,169 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">749,887 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 19pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Prior accident years</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">2,396,446</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,066,290 </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,779,980 </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 19pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total payments</span></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">2,976,983</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,703,459 </span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,529,867 </span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Effect of foreign currency rate changes on current year activity</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">(5,468)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(4,253)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,195 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net reserves for losses and loss adjustment expenses of Markel CATCo Re (see note 17)</span></div></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">347,921</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">— </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">— </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net reserves for losses and loss adjustment expenses of insurance companies sold</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">—</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(2,762)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">— </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net reserves for losses and loss adjustment expenses, end of year</span></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">12,953,014</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11,302,577 </span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">10,485,717 </span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Reinsurance recoverables on unpaid losses, end of year</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">7,994,884</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,876,317 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5,736,659 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Gross reserves for losses and loss adjustment expenses, end of year</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">20,947,898</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">18,178,894 </span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">16,222,376 </span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table>
CY2021Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	18178894000	usd
CY2020Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	16222376000	usd
CY2019Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	14728676000	usd
CY2021Q4	us-gaap	Reinsurance Receivables Incurred But Not Reported Claims ReinsuranceReceivablesIncurredButNotReportedClaims	6876317000	usd
CY2020Q4	us-gaap	Reinsurance Receivables Incurred But Not Reported Claims ReinsuranceReceivablesIncurredButNotReportedClaims	5736659000	usd
CY2019Q4	us-gaap	Reinsurance Receivables Incurred But Not Reported Claims ReinsuranceReceivablesIncurredButNotReportedClaims	5253415000	usd
CY2021Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	11302577000	usd
CY2020Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	10485717000	usd
CY2019Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	9475261000	usd
CY2022Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Opening Balance Adjustments LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseOpeningBalanceAdjustments	-160622000	usd
CY2021Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Opening Balance Adjustments LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseOpeningBalanceAdjustments	-54736000	usd
CY2020Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Opening Balance Adjustments LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseOpeningBalanceAdjustments	68368000	usd
CY2021	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Current Year1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1	637169000	usd
CY2022Q4	mkl	Liability For Unpaid Claims And Claims Adjustment Expense Effect Of Adoption Of Asc326 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseEffectOfAdoptionOfASC326	0	usd
CY2021Q4	mkl	Liability For Unpaid Claims And Claims Adjustment Expense Effect Of Adoption Of Asc326 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseEffectOfAdoptionOfASC326	0	usd
CY2020Q4	mkl	Liability For Unpaid Claims And Claims Adjustment Expense Effect Of Adoption Of Asc326 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseEffectOfAdoptionOfASC326	3849000	usd
CY2022Q4	mkl	Adjusted Liability For Unpaid Claims And Claims Adjustment Expense Net AdjustedLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	11141955000	usd
CY2021Q4	mkl	Adjusted Liability For Unpaid Claims And Claims Adjustment Expense Net AdjustedLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	10430981000	usd
CY2020Q4	mkl	Adjusted Liability For Unpaid Claims And Claims Adjustment Expense Net AdjustedLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	9547478000	usd
CY2022	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	4613035000	usd
CY2021	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	4061000000	usd
CY2020	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	4073325000	usd
CY2022	mkl	Prior Year Claims And Claim Adjustment Expense Including Deposit Liab PriorYearClaimsAndClaimAdjustmentExpenseIncludingDepositLiab	-167446000	usd
CY2021	mkl	Prior Year Claims And Claim Adjustment Expense Including Deposit Liab PriorYearClaimsAndClaimAdjustmentExpenseIncludingDepositLiab	-478930000	usd
CY2020	mkl	Prior Year Claims And Claim Adjustment Expense Including Deposit Liab PriorYearClaimsAndClaimAdjustmentExpenseIncludingDepositLiab	-606414000	usd
CY2022	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1	4445589000	usd
CY2021	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1	3582070000	usd
CY2020	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1	3466911000	usd
CY2022	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Current Year1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1	580537000	usd
CY2020	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Current Year1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1	749887000	usd
CY2022	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Prior Years1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1	2396446000	usd
CY2021	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Prior Years1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1	2066290000	usd
CY2020	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Prior Years1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1	1779980000	usd
CY2022	us-gaap	Payments For Losses And Loss Adjustment Expense PaymentsForLossesAndLossAdjustmentExpense	2976983000	usd
CY2021	us-gaap	Payments For Losses And Loss Adjustment Expense PaymentsForLossesAndLossAdjustmentExpense	2703459000	usd
CY2020	us-gaap	Payments For Losses And Loss Adjustment Expense PaymentsForLossesAndLossAdjustmentExpense	2529867000	usd
CY2022	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Foreign Currency Translation Gain Loss LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseForeignCurrencyTranslationGainLoss	-5468000	usd
CY2021	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Foreign Currency Translation Gain Loss LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseForeignCurrencyTranslationGainLoss	-4253000	usd
CY2020	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Foreign Currency Translation Gain Loss LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseForeignCurrencyTranslationGainLoss	1195000	usd
CY2022	mkl	Liability For Unpaid Claims And Claims Adjustment Expenses Acquisition LiabilityForUnpaidClaimsAndClaimsAdjustmentExpensesAcquisition	347921000	usd
CY2021	mkl	Liability For Unpaid Claims And Claims Adjustment Expenses Acquisition LiabilityForUnpaidClaimsAndClaimsAdjustmentExpensesAcquisition	0	usd
CY2020	mkl	Liability For Unpaid Claims And Claims Adjustment Expenses Acquisition LiabilityForUnpaidClaimsAndClaimsAdjustmentExpensesAcquisition	0	usd
CY2022	mkl	Liability For Unpaid Claims And Claims Adjustment Expenses Business Disposal LiabilityForUnpaidClaimsAndClaimsAdjustmentExpensesBusinessDisposal	0	usd
CY2021	mkl	Liability For Unpaid Claims And Claims Adjustment Expenses Business Disposal LiabilityForUnpaidClaimsAndClaimsAdjustmentExpensesBusinessDisposal	-2762000	usd
CY2020	mkl	Liability For Unpaid Claims And Claims Adjustment Expenses Business Disposal LiabilityForUnpaidClaimsAndClaimsAdjustmentExpensesBusinessDisposal	0	usd
CY2022Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	12953014000	usd
CY2021Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	11302577000	usd
CY2020Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	10485717000	usd
CY2022Q4	us-gaap	Reinsurance Receivables Incurred But Not Reported Claims ReinsuranceReceivablesIncurredButNotReportedClaims	7994884000	usd
CY2021Q4	us-gaap	Reinsurance Receivables Incurred But Not Reported Claims ReinsuranceReceivablesIncurredButNotReportedClaims	6876317000	usd
CY2020Q4	us-gaap	Reinsurance Receivables Incurred But Not Reported Claims ReinsuranceReceivablesIncurredButNotReportedClaims	5736659000	usd
CY2022Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	20947898000	usd
CY2021Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	18178894000	usd
CY2020Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	16222376000	usd
CY2022Q4	mkl	Ibnr Reserves Percentage Of Total Unpaid Losses And Loss Adjustment Expenses IBNRReservesPercentageOfTotalUnpaidLossesAndLossAdjustmentExpenses	0.70
CY2021Q4	mkl	Ibnr Reserves Percentage Of Total Unpaid Losses And Loss Adjustment Expenses IBNRReservesPercentageOfTotalUnpaidLossesAndLossAdjustmentExpenses	0.67
CY2022	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	-167400000	usd
CY2021	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	-479800000	usd
CY2020	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	-606400000	usd
CY2022Q4	us-gaap	Shortduration Insurance Contracts Liability For Unpaid Claims And Allocated Claim Adjustment Expense Net ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet	12693361000	usd
CY2022Q4	us-gaap	Reinsurance Recoverable For Unpaid Claims And Claims Adjustments ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments	7994884000	usd
CY2022Q4	us-gaap	Shortduration Insurance Contracts Liability For Unpaid Claims And Claims Adjustment Expense Accumulated Unallocated Claim Adjustment Expense ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense	326275000	usd
CY2022Q4	mkl	Unpaid Losses And Loss Adjustment Expenses Unamortized Fair Value Adjustment UnpaidLossesAndLossAdjustmentExpensesUnamortizedFairValueAdjustment	-66622000	usd
CY2022Q4	us-gaap	Shortduration Insurance Contracts Liability For Unpaid Claims And Claim Adjustment Expense Aggregate Reconciling Items ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimAdjustmentExpenseAggregateReconcilingItems	259653000	usd
CY2022Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	20947898000	usd
CY2022	us-gaap	Direct Premiums Written DirectPremiumsWritten	10729950000	usd
CY2022	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	2471732000	usd
CY2022	us-gaap	Ceded Premiums Written CededPremiumsWritten	4998292000	usd
CY2022	us-gaap	Premiums Written Net PremiumsWrittenNet	8203390000	usd
CY2022	us-gaap	Direct Premiums Earned DirectPremiumsEarned	10068570000	usd
CY2022	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	2246805000	usd
CY2022	us-gaap	Ceded Premiums Earned CededPremiumsEarned	4727583000	usd
CY2022	us-gaap	Premiums Earned Net PremiumsEarnedNet	7587792000	usd
CY2021	us-gaap	Direct Premiums Written DirectPremiumsWritten	9508184000	usd
CY2021	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	1930498000	usd
CY2021	us-gaap	Ceded Premiums Written CededPremiumsWritten	4318951000	usd
CY2021	us-gaap	Premiums Written Net PremiumsWrittenNet	7119731000	usd
CY2021	us-gaap	Direct Premiums Earned DirectPremiumsEarned	8729068000	usd
CY2021	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	1744346000	usd
CY2021	us-gaap	Ceded Premiums Earned CededPremiumsEarned	3970385000	usd
CY2021	us-gaap	Premiums Earned Net PremiumsEarnedNet	6503029000	usd
CY2020	us-gaap	Direct Premiums Written DirectPremiumsWritten	7753781000	usd
CY2020	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	1512884000	usd
CY2020	us-gaap	Ceded Premiums Written CededPremiumsWritten	3334427000	usd
CY2020	us-gaap	Premiums Written Net PremiumsWrittenNet	5932238000	usd
CY2020	us-gaap	Direct Premiums Earned DirectPremiumsEarned	7442776000	usd
CY2020	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	1469086000	usd
CY2020	us-gaap	Ceded Premiums Earned CededPremiumsEarned	3299657000	usd
CY2020	us-gaap	Premiums Earned Net PremiumsEarnedNet	5612205000	usd
CY2022	mkl	Premiums Percentage Ceded To Gross PremiumsPercentageCededToGross	0.38
CY2021	mkl	Premiums Percentage Ceded To Gross PremiumsPercentageCededToGross	0.38
CY2020	mkl	Premiums Percentage Ceded To Gross PremiumsPercentageCededToGross	0.37
CY2022	us-gaap	Premiums Percentage Assumed To Net PremiumsPercentageAssumedToNet	0.30
CY2021	us-gaap	Premiums Percentage Assumed To Net PremiumsPercentageAssumedToNet	0.27
CY2020	us-gaap	Premiums Percentage Assumed To Net PremiumsPercentageAssumedToNet	0.26
CY2022Q4	us-gaap	Liability For Future Policy Benefits Life LiabilityForFuturePolicyBenefitsLife	102321000	usd
CY2021Q4	us-gaap	Liability For Future Policy Benefits Life LiabilityForFuturePolicyBenefitsLife	113797000	usd
CY2022Q4	us-gaap	Liability For Future Policy Benefits Individual And Group Annuities And Supplementary Contracts LiabilityForFuturePolicyBenefitsIndividualAndGroupAnnuitiesAndSupplementaryContracts	628441000	usd
CY2021Q4	us-gaap	Liability For Future Policy Benefits Individual And Group Annuities And Supplementary Contracts LiabilityForFuturePolicyBenefitsIndividualAndGroupAnnuitiesAndSupplementaryContracts	753971000	usd
CY2022Q4	us-gaap	Liability For Future Policy Benefits Disability And Accident Benefits LiabilityForFuturePolicyBenefitsDisabilityAndAccidentBenefits	28263000	usd
CY2021Q4	us-gaap	Liability For Future Policy Benefits Disability And Accident Benefits LiabilityForFuturePolicyBenefitsDisabilityAndAccidentBenefits	35212000	usd
CY2022Q4	us-gaap	Liability For Future Policy Benefits LiabilityForFuturePolicyBenefits	759025000	usd
CY2021Q4	us-gaap	Liability For Future Policy Benefits LiabilityForFuturePolicyBenefits	902980000	usd
CY2021Q4	mkl	Cumulative Adjustment Lifeand Annuity Benefits CumulativeAdjustmentLifeandAnnuityBenefits	56600000	usd
CY2021	mkl	Adjustmentto Lifeand Annuity Benefits AdjustmenttoLifeandAnnuityBenefits	-63000000	usd
CY2020	mkl	Adjustmentto Lifeand Annuity Benefits AdjustmenttoLifeandAnnuityBenefits	68200000	usd
CY2022Q4	mkl	Traditional Life Interest Rate Average TraditionalLifeInterestRateAverage	0.023
CY2022Q4	mkl	Life And Annuity Benefits Reserve Single Contract Concentration LifeAndAnnuityBenefitsReserveSingleContractConcentration	0.337
CY2022Q4	mkl	Annuities Subject To Discretionary Withdrawal AnnuitiesSubjectToDiscretionaryWithdrawal	0	usd
CY2022Q4	us-gaap	Debt And Capital Lease Obligations DebtAndCapitalLeaseObligations	4103629000	usd
CY2021Q4	us-gaap	Debt And Capital Lease Obligations DebtAndCapitalLeaseObligations	4361266000	usd
CY2022Q4	us-gaap	Debt Instrument Fair Value DebtInstrumentFairValue	3500000000	usd
CY2021Q4	us-gaap	Debt Instrument Fair Value DebtInstrumentFairValue	5000000000	usd
CY2022Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	399604000	usd
CY2022Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	27180000	usd
CY2022Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	24934000	usd
CY2022Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	25637000	usd
CY2022Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	444335000	usd
CY2022Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal After Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive	3226317000	usd
CY2022Q4	mkl	Long Term Debt Maturities Total Future Repayments Of Principal LongTermDebtMaturitiesTotalFutureRepaymentsOfPrincipal	4148007000	usd
CY2022Q4	us-gaap	Debt Instrument Unamortized Discount Premium Net DebtInstrumentUnamortizedDiscountPremiumNet	37572000	usd
CY2022Q4	us-gaap	Deferred Finance Costs Net DeferredFinanceCostsNet	6806000	usd
CY2022Q4	us-gaap	Debt And Capital Lease Obligations DebtAndCapitalLeaseObligations	4103629000	usd
CY2022	us-gaap	Interest Paid InterestPaid	197300000	usd
CY2021	us-gaap	Interest Paid InterestPaid	178600000	usd
CY2020	us-gaap	Interest Paid InterestPaid	178200000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-109311000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	2263748000	usd
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	1003714000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	-39528000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	868445000	usd
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	-3265000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	-148839000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	3132193000	usd
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	1000449000	usd
CY2022	us-gaap	Current Federal State And Local Tax Expense Benefit CurrentFederalStateAndLocalTaxExpenseBenefit	222074000	usd
CY2021	us-gaap	Current Federal State And Local Tax Expense Benefit CurrentFederalStateAndLocalTaxExpenseBenefit	200742000	usd
CY2020	us-gaap	Current Federal State And Local Tax Expense Benefit CurrentFederalStateAndLocalTaxExpenseBenefit	182046000	usd
CY2022	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	12042000	usd
CY2021	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	29811000	usd
CY2020	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	-10631000	usd
CY2022	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	234116000	usd
CY2021	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	230553000	usd
CY2020	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	171415000	usd
CY2022	us-gaap	Deferred Federal State And Local Tax Expense Benefit DeferredFederalStateAndLocalTaxExpenseBenefit	-300850000	usd
CY2021	us-gaap	Deferred Federal State And Local Tax Expense Benefit DeferredFederalStateAndLocalTaxExpenseBenefit	438240000	usd
CY2020	us-gaap	Deferred Federal State And Local Tax Expense Benefit DeferredFederalStateAndLocalTaxExpenseBenefit	-557000	usd
CY2022	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	19098000	usd
CY2021	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	15665000	usd
CY2020	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-2176000	usd
CY2022	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-281752000	usd
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	453905000	usd
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-2733000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-47636000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	684458000	usd
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	168682000	usd
CY2022	us-gaap	Income Taxes Paid IncomeTaxesPaid	251500000	usd
CY2021	us-gaap	Income Taxes Paid IncomeTaxesPaid	204900000	usd
CY2020	us-gaap	Income Taxes Paid IncomeTaxesPaid	241700000	usd
CY2022Q4	us-gaap	Accrued Income Taxes AccruedIncomeTaxes	2200000	usd
CY2021Q4	us-gaap	Accrued Income Taxes AccruedIncomeTaxes	31300000	usd
CY2022Q4	us-gaap	Income Tax Receivable IncomeTaxReceivable	9900000	usd
CY2021Q4	us-gaap	Income Tax Receivable IncomeTaxReceivable	18900000	usd
CY2022	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	-31256000	usd
CY2022	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210	rate
CY2021	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	657760000	usd
CY2021	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210	rate
CY2020	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	210093000	usd
CY2020	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210	rate
CY2022	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	16063000	usd
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	-0.108	rate
CY2021	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	16109000	usd
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.005	rate
CY2020	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	16415000	usd
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.016	rate
CY2022	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	5335000	usd
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	-0.036	rate
CY2021	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	14443000	usd
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0.005	rate
CY2020	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	6500000	usd
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0.006	rate
CY2022	us-gaap	Income Tax Reconciliation Nondeductible Expense Impairment Losses IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses	16800000	usd
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Impairment Losses EffectiveIncomeTaxRateReconciliationNondeductibleExpenseImpairmentLosses	-0.113	rate
CY2021	us-gaap	Income Tax Reconciliation Nondeductible Expense Impairment Losses IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses	0	usd
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Impairment Losses EffectiveIncomeTaxRateReconciliationNondeductibleExpenseImpairmentLosses	0.000	rate
CY2020	us-gaap	Income Tax Reconciliation Nondeductible Expense Impairment Losses IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses	0	usd
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Impairment Losses EffectiveIncomeTaxRateReconciliationNondeductibleExpenseImpairmentLosses	0.000	rate
CY2022	mkl	Markel Cat Co Re Income Not Subject To Tax Amount MarkelCATCoReIncomeNotSubjectToTaxAmount	18871000	usd
CY2022	mkl	Markel Cat Co Re Income Not Subject To Tax Percent MarkelCATCoReIncomeNotSubjectToTaxPercent	0.127	rate
CY2021	mkl	Markel Cat Co Re Income Not Subject To Tax Amount MarkelCATCoReIncomeNotSubjectToTaxAmount	0	usd
CY2021	mkl	Markel Cat Co Re Income Not Subject To Tax Percent MarkelCATCoReIncomeNotSubjectToTaxPercent	0.000	rate
CY2020	mkl	Markel Cat Co Re Income Not Subject To Tax Amount MarkelCATCoReIncomeNotSubjectToTaxAmount	0	usd
CY2020	mkl	Markel Cat Co Re Income Not Subject To Tax Percent MarkelCATCoReIncomeNotSubjectToTaxPercent	0.000	rate
CY2022	mkl	Nondeductible Deductible Losses On Certain Foreign Investments Amount NondeductibleDeductibleLossesOnCertainForeignInvestmentsAmount	-160000	usd
CY2022	mkl	Nondeductible Deductible Losses On Certain Foreign Investments Percent NondeductibleDeductibleLossesOnCertainForeignInvestmentsPercent	-0.001	rate
CY2021	mkl	Nondeductible Deductible Losses On Certain Foreign Investments Amount NondeductibleDeductibleLossesOnCertainForeignInvestmentsAmount	1240000	usd
CY2021	mkl	Nondeductible Deductible Losses On Certain Foreign Investments Percent NondeductibleDeductibleLossesOnCertainForeignInvestmentsPercent	-0.000	rate
CY2020	mkl	Nondeductible Deductible Losses On Certain Foreign Investments Amount NondeductibleDeductibleLossesOnCertainForeignInvestmentsAmount	-38666000	usd
CY2020	mkl	Nondeductible Deductible Losses On Certain Foreign Investments Percent NondeductibleDeductibleLossesOnCertainForeignInvestmentsPercent	0.039	rate
CY2022	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-3421000	usd
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.023	rate
CY2021	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	27124000	usd
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.009	rate
CY2020	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	7170000	usd
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.007	rate
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-47636000	usd
CY2022	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.320	rate
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	684458000	usd
CY2021	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.219	rate
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	168682000	usd
CY2020	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.168	rate
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Loss Reserves DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsLossReserves	170518000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Loss Reserves DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsLossReserves	186759000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Unearned Premiums Reserve DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsUnearnedPremiumsReserve	161243000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Unearned Premiums Reserve DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsUnearnedPremiumsReserve	139350000	usd
CY2022Q4	mkl	Deferred Tax Assets Tax Deferred Expense Lease Liabilities DeferredTaxAssetsTaxDeferredExpenseLeaseLiabilities	132735000	usd
CY2021Q4	mkl	Deferred Tax Assets Tax Deferred Expense Lease Liabilities DeferredTaxAssetsTaxDeferredExpenseLeaseLiabilities	135795000	usd
CY2022Q4	mkl	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Life And Annuity Benefits DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsLifeAndAnnuityBenefits	54893000	usd
CY2021Q4	mkl	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Life And Annuity Benefits DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsLifeAndAnnuityBenefits	78777000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Other DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsOther	39469000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Other DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsOther	50806000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	25305000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	47510000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards DeferredTaxAssetsTaxCreditCarryforwards	18264000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards DeferredTaxAssetsTaxCreditCarryforwards	21734000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	65250000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	66951000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	667677000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	727682000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	16943000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	23352000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	650734000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	704330000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Other Comprehensive Income DeferredTaxLiabilitiesOtherComprehensiveIncome	761421000	usd
CY2021Q4	us-gaap	Deferred Tax Liabilities Other Comprehensive Income DeferredTaxLiabilitiesOtherComprehensiveIncome	1401871000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssets	180186000	usd
CY2021Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssets	185195000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Policy Acquisition Cost DeferredTaxLiabilitiesDeferredExpenseDeferredPolicyAcquisitionCost	161220000	usd
CY2021Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Policy Acquisition Cost DeferredTaxLiabilitiesDeferredExpenseDeferredPolicyAcquisitionCost	146601000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	144259000	usd
CY2021Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	126846000	usd
CY2022Q4	mkl	Deferred Tax Liabilities Rightofuse Lease Assets DeferredTaxLiabilitiesRightofuseLeaseAssets	127398000	usd
CY2021Q4	mkl	Deferred Tax Liabilities Rightofuse Lease Assets DeferredTaxLiabilitiesRightofuseLeaseAssets	127313000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	113065000	usd
CY2021Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	129866000	usd
CY2022Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	1487549000	usd
CY2021Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	2117692000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	836815000	usd
CY2021Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	1413362000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards DeferredTaxAssetsTaxCreditCarryforwards	18300000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	667700000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	16900000	usd
CY2022Q4	mkl	Gross Deferred Tax Assets Estimated Amount Realized Through Reversalof Deferred Tax Liabilities GrossDeferredTaxAssetsEstimatedAmountRealizedThroughReversalofDeferredTaxLiabilities	650700000	usd
CY2022	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	57900000	usd
CY2021	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	52700000	usd
CY2020	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	48600000	usd
CY2022Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	108500000	usd
CY2021Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	210200000	usd
CY2022Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	171700000	usd
CY2021Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	243600000	usd
CY2022Q4	mkl	Cash Funding Used To Purchase Markel Cat Co Funds Interests In Markel Cat Co Re CashFundingUsedToPurchaseMarkelCATCoFundsInterestsInMarkelCATCoRe	45100000	usd
CY2022	mkl	Returned Capital From Markel Cat Co Re ReturnedCapitalFromMarkelCATCoRe	24900000	usd
CY2022Q4	mkl	Investment In Markel Cat Co Re InvestmentInMarkelCATCoRe	20100000	usd
CY2022Q4	mkl	Percentage Of Markel Cat Co Re Net Equity By The Company PercentageOfMarkelCATCoReNetEquityByTheCompany	0.23
CY2022Q4	mkl	Investment In Markel Cat Co Re InvestmentInMarkelCATCoRe	20100000	usd
CY2022Q4	mkl	Tail Risk Cover In Cat Co Transaction TailRiskCoverInCATCoTransaction	142700000	usd
CY2022Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	50000000	shares
CY2022Q4	us-gaap	Common Stock No Par Value CommonStockNoParValue	0
CY2022Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	10000000	shares
CY2020Q2	mkl	Issuers Redemption Option Period To Redeem After A Redemption Event IssuersRedemptionOptionPeriodToRedeemAfterARedemptionEvent	P90D
CY2020Q2	mkl	Issuers Redemption Option Period To Redeem After A Redemption Event IssuersRedemptionOptionPeriodToRedeemAfterARedemptionEvent	P90D
CY2020Q2	us-gaap	Preferred Stock Redemption Price Per Share PreferredStockRedemptionPricePerShare	1000
CY2022	us-gaap	Dividends Preferred Stock DividendsPreferredStock	36000000	usd
CY2022	us-gaap	Preferred Stock Dividends Per Share Declared PreferredStockDividendsPerShareDeclared	60.00
CY2022	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-250123000	usd
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	2389003000	usd
CY2020	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	797630000	usd
CY2022	us-gaap	Temporary Equity Accretion To Redemption Value Adjustment TemporaryEquityAccretionToRedemptionValueAdjustment	69896000	usd
CY2021	us-gaap	Temporary Equity Accretion To Redemption Value Adjustment TemporaryEquityAccretionToRedemptionValueAdjustment	-46874000	usd
CY2020	us-gaap	Temporary Equity Accretion To Redemption Value Adjustment TemporaryEquityAccretionToRedemptionValueAdjustment	28705000	usd
CY2022	mkl	Adjusted Net Income Loss AdjustedNetIncomeLoss	-320019000	usd
CY2021	mkl	Adjusted Net Income Loss AdjustedNetIncomeLoss	2435877000	usd
CY2020	mkl	Adjusted Net Income Loss AdjustedNetIncomeLoss	768925000	usd
CY2022	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	13580000	shares
CY2021	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	13768000	shares
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	13811000	shares
CY2022	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	13580000	shares
CY2021	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	13800000	shares
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	13823000	shares
CY2022	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-23.57
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	176.92
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	55.67
CY2022	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-23.57
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	176.51
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	55.63
CY2022Q4	mkl	Cash Funding Used To Purchase Markel Cat Co Funds Interests In Markel Cat Co Re CashFundingUsedToPurchaseMarkelCATCoFundsInterestsInMarkelCATCoRe	45100000	usd
CY2022Q4	mkl	Tail Risk Cover In Cat Co Transaction TailRiskCoverInCATCoTransaction	142700000	usd
CY2022Q4	mkl	Additional Payments Made Net Of Insurance Proceeds To Investors By Markel AdditionalPaymentsMadeNetOfInsuranceProceedsToInvestorsByMarkel	101900000	usd
CY2022Q4	mkl	Funds At Lloyds FundsAtLloyds	873000000	usd
CY2022Q4	mkl	Fundsat Lloyds Holding Company FundsatLloydsHoldingCompany	335400000	usd
CY2022	dei	Auditor Name AuditorName	KPMG LLP
CY2022	dei	Auditor Location AuditorLocation	Richmond, VA
CY2022	dei	Auditor Firm AuditorFirmId	185

Files In Submission

Name	View Source	Status
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$MKL
MARKEL GROUP INC. Stock $mkl

2023 Q1 Form 10-K Financial Statement

#000109634323000033 Filed on February 17, 2023

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$MKL MARKEL GROUP INC. Stock $mkl

2023 Q1 Form 10-K Financial Statement

#000109634323000033 Filed on February 17, 2023

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$MKL
MARKEL GROUP INC. Stock $mkl