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v3.20.2

Label | Element | Value
--- | --- | ---
Noncontrolling Interest [Member] |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance | us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance1 | $ 7,549,000
Cumulative Effect of Adoption of ASU No 2016-13, Net of Taxes | mkl_CumulativeEffectofAdoptionofASUNo201613NetofTaxes | 0
Common Stock [Member] |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance | us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance1 | $ 3,404,919,000
Shares, Issued | us-gaap_SharesIssued | 13,794,000
Retained Earnings [Member] |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance | us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance1 | $ 7,453,349,000
AOCI Attributable to Parent [Member] |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance | us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance1 | 208,772,000
Cumulative Effect of Adoption of ASU No 2016-13, Net of Taxes | mkl_CumulativeEffectofAdoptionofASUNo201613NetofTaxes | 0
Parent [Member] |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance | us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance1 | 11,067,040,000
Cumulative Effect of Adoption of ASU No 2016-13, Net of Taxes | mkl_CumulativeEffectofAdoptionofASUNo201613NetofTaxes | (3,827,000)
Redeemable Noncontrolling Interests, Temporary Equity [Member] |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance | us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance1 | 177,562,000
Cumulative Effect of Adoption of ASU No 2016-13, Net of Taxes | mkl_CumulativeEffectofAdoptionofASUNo201613NetofTaxes | 0
Total Equity [Member] |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance | us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance1 | 11,074,589,000
Cumulative Effect of Adoption of ASU No 2016-13, Net of Taxes | mkl_CumulativeEffectofAdoptionofASUNo201613NetofTaxes | (3,827,000)
Preferred Stock [Member] |  |
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance | us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance1 | $ 0
Shares, Issued | us-gaap_SharesIssued | 0

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- Definition Cumulative Effect of Adoption of ASU No 2016-13, Net of Taxes + References No definition available. + Details
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Namespace Prefix: | mkl_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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- Definition Number of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 + Details
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- Definition Amount of stockholders' equity including the portion attributable to noncontrolling interests, after the cumulative effect adjustment of a new accounting principle applied in the period of adoption. + References No definition available. + Details
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