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Pay vs Performance Disclosure | 12 Months Ended
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Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($)
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure, Table |  | As required and set forth by Section 953(a) of the Dodd-Frank Act, and Item 402(v) of Regulation S-K, we are providing the following information about the relationship between executive compensation paid to our named executive officers and the financial performance of the Company. Pay Versus Performance Table
|  |  |  |  |  | Average Summary Compensation Table Total for Non-PEO Named Executive Officers |  | Average Compensation Actually Paid to Non-PEO Named Executive Officers f |  | Value of Initial Fixed $100 Investment based on: |  |  |  | Company-Selected Measure k
|  | Summary Compensation Table Total for: |  | Compensation Actually Paid to:e |  |  |  | Total Shareholder Return g |  | Peer Group Total Shareholder Return h |  |  |  | 5-Year CAGR in Book Value Per Share j |  | 5-Year CAGR in Total Shareholder Return j
Year |  | PEO or Co-PEO 1 |  | Co-PEO 2 |  | PEO or Co-PEO 1 g |  | Co-PEO 2 g |  |  |  |  |  | Net Income (Loss) |  |
2023 a |  | $8,068,291 |  |  | N/A |  | $8,559,693 |  |  | N/A |  | $2,469,487 |  |  | $2,542,584 |  |  | $124.21 |  |  | $164.40 |  |  | $2,101,090,000 |  |  | 11% |  | 6%
2022 b |  | $3,991,434 |  |  | $3,981,772 |  |  | $4,408,196 |  |  | $4,398,534 |  |  | $1,668,541 |  |  | $1,763,178 |  |  | $115.25 |  |  | $144.76 |  |  | ($101,203,000) |  | i | 7% | i | 3%
2021 c |  | $4,639,603 |  |  | $4,630,441 |  |  | $5,625,544 |  |  | $5,616,382 |  |  | $2,027,504 |  |  | $2,324,107 |  |  | $107.95 |  |  | $125.88 |  |  | $2,447,735,000 |  | i | 11% |  | 6%
2020 d |  | $4,183,420 |  |  | $4,192,222 |  |  | $3,712,379 |  |  | $3,721,181 |  |  | $1,893,420 |  |  | $1,766,975 |  |  | $90.39 |  |  | $103.11 |  |  | $831,767,000 |  |  | 10% |  | 3%
a The named executive officers for the 2023 fiscal year included Thomas S. Gayner, as PEO, and Michael R. Heaton, Jeremy A. Noble, Richard R. Grinnan, Brian J. Costanzo and Teresa S. Gendron as the non-PEO named executive officers. b The named executive officers for the 2022 fiscal year included Thomas S. Gayner, as Co-PEO 1, and Richard R. Whitt, III, as Co-PEO 2, and Michael R. Heaton, Jeremy A. Noble, Robert C. Cox and Richard R. Grinnan as the non-PEO named executive officers. c The named executive officers for the 2021 fiscal year included Thomas S. Gayner, as Co-PEO 1, and Richard R. Whitt, III, as Co-PEO 2, and Michael R. Heaton, Jeremy A. Noble, Robert C. Cox and Bradley J. Kiscaden as the non-PEO named executive officers. d The named executive officers for the 2020 fiscal year included Thomas S. Gayner, as Co-PEO 1, and Richard R. Whitt, III, as Co-PEO 2, and Jeremy A. Noble, Robert C. Cox, Bradley J. Kiscaden and Richard R. Grinnan as the non-PEO named executive officers. e The amounts set out in these columns (i) represent the amounts of “compensation actually paid” to the PEO, or each Co-PEO, as computed in accordance with Item 402(v) of Regulation S-K, and (ii) do not reflect the actual amounts of compensation earned by or paid to the PEO, or each Co-PEO, during the applicable fiscal year. f The amounts set out in this column (i) represent the average amounts of “compensation actually paid” to the non-PEO named executed officers, as computed in accordance with Item 402(v) of Regulation S-K, and (ii) do not reflect the actual average amounts of compensation earned by or paid to the non-PEO named executive officers during the applicable fiscal year. g The amounts set out in the table below have been deducted from or added to the Total Compensation amounts reported in the Summary Compensation Table for the PEO, each Co-PEO, and non-PEO named executive officers to determine Compensation Actually Paid:
|  |  |  | Starting Amount: |  |  |  |  |  |  |  |  |  |  |  |
|  |  |  |  | Deducted: |  | Added: |  | Added: |  | Added: |  | Added: |  | Adjusted Amount:
Year |  | Named Executive Officers |  | Summary Compensation Table Total |  | The grant date fair value of all stock awards granted in the applicable year, as reported in the Summary Compensation Table |  | The fair value as of the end of the covered fiscal year of all stock awards granted during the covered fiscal year that were outstanding and unvested as of the end of the covered fiscal year |  | The change (positive or negative) as of the end of the covered fiscal year (from the end of the prior fiscal year) in fair value of any stock awards granted in any prior fiscal year that are outstanding and unvested as of the end of the covered fiscal year |  | For stock awards that are granted and vest in the same covered fiscal year, the fair value as of the vesting date |  | The change (positive or negative) as of the vesting date (from the end of the prior fiscal year) in fair value of any stock awards granted in any prior fiscal year for which all vesting conditions were satisfied at the end of or during the covered fiscal year |  | Compensation Actually Paid
2023 |  | PEO |  | $8,068,291 |  |  | $5,387,107 |  |  | $5,364,382 |  |  | $351,471 |  |  | — |  |  | $162,656 |  |  | $8,559,693 |
|  | Non-PEO NEOs* |  | $2,469,487 |  |  | $1,100,028 |  |  | $903,624 |  |  | $54,462 |  |  | $195,011 |  |  | $20,028 |  |  | $2,542,584 |
2022 |  | Co-PEO 1 |  | $3,991,434 |  |  | $2,100,000 |  |  | $2,052,649 |  | ** | $318,514 |  |  | — |  |  | $145,599 |  |  | $4,408,196 |
|  | Co-PEO 2 |  | $3,981,772 |  |  | $2,100,000 |  |  | $2,052,649 |  | ** | — |  |  | — |  |  | $464,113 |  |  | $4,398,534 |
|  | Non-PEO NEOs* |  | $1,668,541 |  |  | $615,625 |  |  | $601,434 |  | ** | $79,545 |  |  | — |  |  | $29,283 |  |  | $1,763,178 |
|  | * As an average.
|  | ** Reflects corrections to amounts previously reported for the 2022 year-end fair value of stock awards granted during 2022 that were outstanding and unvested as of the end of 2022.
h Dow Jones U.S. Property & Casualty Insurance Companies Index. i Amounts are as disclosed in the Pay Versus Performance Table in the Company’s 2023 Proxy Statement. Due to a restatement as a result of the required adoption of Financial Accounting Standards Board (FASB) Accounting Standards Update (ASU) No. 2018-12, Financial Services—Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts effective January 1, 2023, net income for 2022 and 2021 has been restated to $(103,357,000) and $2,445,867,000, respectively. j The term CAGR means compound annual growth rate. k These Company-selected financial performance measures represent the most important financial performance measures used by the Company and were weighted equally to link compensation actually paid to the Company’s named executed officers (excluding Mr. Costanzo and Ms. Gendron), for the most recently completed fiscal year, to the Company’s performance. See “Cash Incentive Compensation for Brian J. Costanzo” and “Compensation for Teresa S. Gendron” for a discussion of performance measures for Mr. Costanzo and Ms. Gendron, respectively. |  |  |  |  |  |  |
Named Executive Officers, Footnote |  | The named executive officers for the 2023 fiscal year included Thomas S. Gayner, as PEO, and Michael R. Heaton, Jeremy A. Noble, Richard R. Grinnan, Brian J. Costanzo and Teresa S. Gendron as the non-PEO named executive officers. |  | The named executive officers for the 2022 fiscal year included Thomas S. Gayner, as Co-PEO 1, and Richard R. Whitt, III, as Co-PEO 2, and Michael R. Heaton, Jeremy A. Noble, Robert C. Cox and Richard R. Grinnan as the non-PEO named executive officers. |  | The named executive officers for the 2021 fiscal year included Thomas S. Gayner, as Co-PEO 1, and Richard R. Whitt, III, as Co-PEO 2, and Michael R. Heaton, Jeremy A. Noble, Robert C. Cox and Bradley J. Kiscaden as the non-PEO named executive officers. |  | The named executive officers for the 2020 fiscal year included Thomas S. Gayner, as Co-PEO 1, and Richard R. Whitt, III, as Co-PEO 2, and Jeremy A. Noble, Robert C. Cox, Bradley J. Kiscaden and Richard R. Grinnan as the non-PEO named executive officers. |
Peer Group Issuers, Footnote |  | Dow Jones U.S. Property & Casualty Insurance Companies Index. |  |  |  |  |  |  |
PEO Total Compensation Amount | [1] | $ 8,068,291 |  |  |  |  |  |  |
PEO Actually Paid Compensation Amount | [1],[2],[3] | $ 8,559,693 |  |  |  |  |  |  |
Adjustment To PEO Compensation, Footnote |  | The amounts set out in the table below have been deducted from or added to the Total Compensation amounts reported in the Summary Compensation Table for the PEO, each Co-PEO, and non-PEO named executive officers to determine Compensation Actually Paid:
|  |  |  | Starting Amount: |  |  |  |  |  |  |  |  |  |  |  |
|  |  |  |  | Deducted: |  | Added: |  | Added: |  | Added: |  | Added: |  | Adjusted Amount:
Year |  | Named Executive Officers |  | Summary Compensation Table Total |  | The grant date fair value of all stock awards granted in the applicable year, as reported in the Summary Compensation Table |  | The fair value as of the end of the covered fiscal year of all stock awards granted during the covered fiscal year that were outstanding and unvested as of the end of the covered fiscal year |  | The change (positive or negative) as of the end of the covered fiscal year (from the end of the prior fiscal year) in fair value of any stock awards granted in any prior fiscal year that are outstanding and unvested as of the end of the covered fiscal year |  | For stock awards that are granted and vest in the same covered fiscal year, the fair value as of the vesting date |  | The change (positive or negative) as of the vesting date (from the end of the prior fiscal year) in fair value of any stock awards granted in any prior fiscal year for which all vesting conditions were satisfied at the end of or during the covered fiscal year |  | Compensation Actually Paid
2023 |  | PEO |  | $8,068,291 |  |  | $5,387,107 |  |  | $5,364,382 |  |  | $351,471 |  |  | — |  |  | $162,656 |  |  | $8,559,693 |
|  | Non-PEO NEOs* |  | $2,469,487 |  |  | $1,100,028 |  |  | $903,624 |  |  | $54,462 |  |  | $195,011 |  |  | $20,028 |  |  | $2,542,584 |
2022 |  | Co-PEO 1 |  | $3,991,434 |  |  | $2,100,000 |  |  | $2,052,649 |  | ** | $318,514 |  |  | — |  |  | $145,599 |  |  | $4,408,196 |
|  | Co-PEO 2 |  | $3,981,772 |  |  | $2,100,000 |  |  | $2,052,649 |  | ** | — |  |  | — |  |  | $464,113 |  |  | $4,398,534 |
|  | Non-PEO NEOs* |  | $1,668,541 |  |  | $615,625 |  |  | $601,434 |  | ** | $79,545 |  |  | — |  |  | $29,283 |  |  | $1,763,178 |
|  | * As an average.
|  | ** Reflects corrections to amounts previously reported for the 2022 year-end fair value of stock awards granted during 2022 that were outstanding and unvested as of the end of 2022.
Non-PEO NEO Average Total Compensation Amount |  | $ 2,469,487 | [1] | $ 1,668,541 | [4] | $ 2,027,504 | [5] | $ 1,893,420 | [6]
Non-PEO NEO Average Compensation Actually Paid Amount | [7] | $ 2,542,584 | [1] | 1,763,178 | [4] | 2,324,107 | [5] | 1,766,975 | [6]
Adjustment to Non-PEO NEO Compensation Footnote |  | The amounts set out in the table below have been deducted from or added to the Total Compensation amounts reported in the Summary Compensation Table for the PEO, each Co-PEO, and non-PEO named executive officers to determine Compensation Actually Paid:
|  |  |  | Starting Amount: |  |  |  |  |  |  |  |  |  |  |  |
|  |  |  |  | Deducted: |  | Added: |  | Added: |  | Added: |  | Added: |  | Adjusted Amount:
Year |  | Named Executive Officers |  | Summary Compensation Table Total |  | The grant date fair value of all stock awards granted in the applicable year, as reported in the Summary Compensation Table |  | The fair value as of the end of the covered fiscal year of all stock awards granted during the covered fiscal year that were outstanding and unvested as of the end of the covered fiscal year |  | The change (positive or negative) as of the end of the covered fiscal year (from the end of the prior fiscal year) in fair value of any stock awards granted in any prior fiscal year that are outstanding and unvested as of the end of the covered fiscal year |  | For stock awards that are granted and vest in the same covered fiscal year, the fair value as of the vesting date |  | The change (positive or negative) as of the vesting date (from the end of the prior fiscal year) in fair value of any stock awards granted in any prior fiscal year for which all vesting conditions were satisfied at the end of or during the covered fiscal year |  | Compensation Actually Paid
2023 |  | PEO |  | $8,068,291 |  |  | $5,387,107 |  |  | $5,364,382 |  |  | $351,471 |  |  | — |  |  | $162,656 |  |  | $8,559,693 |
|  | Non-PEO NEOs* |  | $2,469,487 |  |  | $1,100,028 |  |  | $903,624 |  |  | $54,462 |  |  | $195,011 |  |  | $20,028 |  |  | $2,542,584 |
2022 |  | Co-PEO 1 |  | $3,991,434 |  |  | $2,100,000 |  |  | $2,052,649 |  | ** | $318,514 |  |  | — |  |  | $145,599 |  |  | $4,408,196 |
|  | Co-PEO 2 |  | $3,981,772 |  |  | $2,100,000 |  |  | $2,052,649 |  | ** | — |  |  | — |  |  | $464,113 |  |  | $4,398,534 |
|  | Non-PEO NEOs* |  | $1,668,541 |  |  | $615,625 |  |  | $601,434 |  | ** | $79,545 |  |  | — |  |  | $29,283 |  |  | $1,763,178 |
|  | * As an average.
|  | ** Reflects corrections to amounts previously reported for the 2022 year-end fair value of stock awards granted during 2022 that were outstanding and unvested as of the end of 2022.
Compensation Actually Paid vs. Total Shareholder Return |  |  |  |  |  |  |  |  |
Compensation Actually Paid vs. Net Income |  |  |  |  |  |  |  |  |
Compensation Actually Paid vs. Company Selected Measure |  |  |  |  |  |  |  |  |
Total Shareholder Return Vs Peer Group |  |  |  |  |  |  |  |  |
Tabular List, Table |  |
Most Important Financial Performance Measures Used by the Company to Link Compensation Actually Paid to Company’s Performance
5-year CAGR in the Company’s book value per share
5-year CAGR in the Company’s total shareholder return
Total Shareholder Return Amount | [2] | $ 124.21 | [1] | 115.25 | [4] | 107.95 | [5] | 90.39 | [6]
Peer Group Total Shareholder Return Amount | [8] | 164.40 | [1] | 144.76 | [4] | 125.88 | [5] | 103.11 | [6]
Net Income (Loss) |  | $ 2,101,090,000 | [1] | $ (101,203,000) | [4],[9] | $ 2,447,735,000 | [5],[9] | $ 831,767,000 | [6]
Company Selected Measure Amount | [10],[11] | 0.11 | [1] | 0.07 | [4],[9] | 0.11 | [5] | 0.10 | [6]
Additional 402(v) Disclosure |  | The following graphs represent the relationship between “compensation actually paid,” as reflected in the Pay Versus Performance Table, to the Company’s PEO, or each Co-PEO, as applicable, and other named executive officers (expressed as an average) and the performance measures included in the Pay Versus Performance Table (Total Shareholder Return, Peer Group Total Shareholder Return, Net Income, 5-Year CAGR in Book Value Per Share and 5-Year CAGR in Total Shareholder Return). |  |  |  |  |  |  |
Measure:: 2 |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Other Performance Measure, Amount | [10],[11] | 0.06 | [1] | 0.03 | [4] | 0.06 | [5] | 0.03 | [6]
Co-PEO 1 [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
PEO Total Compensation Amount |  |  |  | $ 3,991,434 | [4] | $ 4,639,603 | [5] | $ 4,183,420 | [6]
PEO Actually Paid Compensation Amount | [2],[3] |  |  | $ 4,408,196 | [4] | $ 5,625,544 | [5] | $ 3,712,379 | [6]
PEO Name |  |  |  | Thomas S. Gayner |  | Thomas S. Gayner |  | Thomas S. Gayner |
Co-PEO 2 [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
PEO Total Compensation Amount |  |  |  | $ 3,981,772 | [4] | $ 4,630,441 | [5] | $ 4,192,222 | [6]
PEO Actually Paid Compensation Amount | [2],[3] |  |  | $ 4,398,534 | [4] | $ 5,616,382 | [5] | $ 3,721,181 | [6]
PEO Name |  |  |  | Richard R. Whitt, III |  | Richard R. Whitt, III |  | Richard R. Whitt, III |
PEO [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
PEO Name |  | Thomas S. Gayner |  |  |  |  |  |  |
PEO [Member] | Measure:: 1 |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Name |  | 5-year CAGR in the Company’s book value per share |  |  |  |  |  |  |
PEO [Member] | Measure:: 2 |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Name |  | 5-year CAGR in the Company’s total shareholder return |  |  |  |  |  |  |
PEO [Member] | The Grant Date Fair Value of All Stock Awards Granted in the Applicable Year, as Reported in the Summary Compensation Table [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  | $ 5,387,107 |  |  |  |  |  |  |
PEO [Member] | The Fair Value as of the End of the Covered Fiscal Year of All Stock Awards Granted During the Covered Fiscal Year That were Outstanding and Unvested as of the End of the Covered Fiscal Year [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  | 5,364,382 |  |  |  |  |  |  |
PEO [Member] | The Change as of the End of the Covered Fiscal Year in Fair Value of Any Stock Awards Granted in Any Prior Fiscal Year that are Outstanding and Unvested as of the End of the Covered Fiscal Year [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  | 351,471 |  |  |  |  |  |  |
PEO [Member] | For stock awards that are granted and vest in the same covered fiscal year, the fair value as of the vesting date [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  | 0 |  |  |  |  |  |  |
PEO [Member] | The Change as of the Vesting Date in Fair Value of Any Stock Awards Granted in Any Prior Fiscal Year for Which All Vesting Conditions were Satisfied at the End of or During the Covered Fiscal Year [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  | 162,656 |  |  |  |  |  |  |
PEO [Member] | Co-PEO 1 [Member] | The Grant Date Fair Value of All Stock Awards Granted in the Applicable Year, as Reported in the Summary Compensation Table [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  |  |  | $ 2,100,000 |  |  |  |  |
PEO [Member] | Co-PEO 1 [Member] | The Fair Value as of the End of the Covered Fiscal Year of All Stock Awards Granted During the Covered Fiscal Year That were Outstanding and Unvested as of the End of the Covered Fiscal Year [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  |  |  | 2,052,649 |  |  |  |  |
PEO [Member] | Co-PEO 1 [Member] | The Change as of the End of the Covered Fiscal Year in Fair Value of Any Stock Awards Granted in Any Prior Fiscal Year that are Outstanding and Unvested as of the End of the Covered Fiscal Year [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  |  |  | 318,514 |  |  |  |  |
PEO [Member] | Co-PEO 1 [Member] | For stock awards that are granted and vest in the same covered fiscal year, the fair value as of the vesting date [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  |  |  | 0 |  |  |  |  |
PEO [Member] | Co-PEO 1 [Member] | The Change as of the Vesting Date in Fair Value of Any Stock Awards Granted in Any Prior Fiscal Year for Which All Vesting Conditions were Satisfied at the End of or During the Covered Fiscal Year [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  |  |  | 145,599 |  |  |  |  |
PEO [Member] | Co-PEO 2 [Member] | The Grant Date Fair Value of All Stock Awards Granted in the Applicable Year, as Reported in the Summary Compensation Table [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  |  |  | 2,100,000 |  |  |  |  |
PEO [Member] | Co-PEO 2 [Member] | The Fair Value as of the End of the Covered Fiscal Year of All Stock Awards Granted During the Covered Fiscal Year That were Outstanding and Unvested as of the End of the Covered Fiscal Year [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  |  |  | 2,052,649 |  |  |  |  |
PEO [Member] | Co-PEO 2 [Member] | The Change as of the End of the Covered Fiscal Year in Fair Value of Any Stock Awards Granted in Any Prior Fiscal Year that are Outstanding and Unvested as of the End of the Covered Fiscal Year [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  |  |  | 0 |  |  |  |  |
PEO [Member] | Co-PEO 2 [Member] | For stock awards that are granted and vest in the same covered fiscal year, the fair value as of the vesting date [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  |  |  | 0 |  |  |  |  |
PEO [Member] | Co-PEO 2 [Member] | The Change as of the Vesting Date in Fair Value of Any Stock Awards Granted in Any Prior Fiscal Year for Which All Vesting Conditions were Satisfied at the End of or During the Covered Fiscal Year [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  |  |  | 464,113 |  |  |  |  |
Non-PEO NEO | The Grant Date Fair Value of All Stock Awards Granted in the Applicable Year, as Reported in the Summary Compensation Table [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  | 1,100,028 |  | 615,625 |  |  |  |  |
Non-PEO NEO | The Fair Value as of the End of the Covered Fiscal Year of All Stock Awards Granted During the Covered Fiscal Year That were Outstanding and Unvested as of the End of the Covered Fiscal Year [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  | 903,624 |  | 601,434 |  |  |  |  |
Non-PEO NEO | The Change as of the End of the Covered Fiscal Year in Fair Value of Any Stock Awards Granted in Any Prior Fiscal Year that are Outstanding and Unvested as of the End of the Covered Fiscal Year [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  | 54,462 |  | 79,545 |  |  |  |  |
Non-PEO NEO | For stock awards that are granted and vest in the same covered fiscal year, the fair value as of the vesting date [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  | 195,011 |  | 0 |  |  |  |  |
Non-PEO NEO | The Change as of the Vesting Date in Fair Value of Any Stock Awards Granted in Any Prior Fiscal Year for Which All Vesting Conditions were Satisfied at the End of or During the Covered Fiscal Year [Member] |  |  |  |  |  |  |  |  |
Pay vs Performance Disclosure |  |  |  |  |  |  |  |  |
Adjustment to Compensation, Amount |  | $ 20,028 |  | $ 29,283 |  |  |  |  |
[1] | The named executive officers for the 2023 fiscal year included Thomas S. Gayner, as PEO, and Michael R. Heaton, Jeremy A. Noble, Richard R. Grinnan, Brian J. Costanzo and Teresa S. Gendron as the non-PEO named executive officers.
[2] | The amounts set out in the table below have been deducted from or added to the Total Compensation amounts reported in the Summary Compensation Table for the PEO, each Co-PEO, and non-PEO named executive officers to determine Compensation Actually Paid:
|  |  |  | Starting Amount: |  |  |  |  |  |  |  |  |  |  |  |
|  |  |  |  | Deducted: |  | Added: |  | Added: |  | Added: |  | Added: |  | Adjusted Amount:
Year |  | Named Executive Officers |  | Summary Compensation Table Total |  | The grant date fair value of all stock awards granted in the applicable year, as reported in the Summary Compensation Table |  | The fair value as of the end of the covered fiscal year of all stock awards granted during the covered fiscal year that were outstanding and unvested as of the end of the covered fiscal year |  | The change (positive or negative) as of the end of the covered fiscal year (from the end of the prior fiscal year) in fair value of any stock awards granted in any prior fiscal year that are outstanding and unvested as of the end of the covered fiscal year |  | For stock awards that are granted and vest in the same covered fiscal year, the fair value as of the vesting date |  | The change (positive or negative) as of the vesting date (from the end of the prior fiscal year) in fair value of any stock awards granted in any prior fiscal year for which all vesting conditions were satisfied at the end of or during the covered fiscal year |  | Compensation Actually Paid
2023 |  | PEO |  | $8,068,291 |  |  | $5,387,107 |  |  | $5,364,382 |  |  | $351,471 |  |  | — |  |  | $162,656 |  |  | $8,559,693 |
|  | Non-PEO NEOs* |  | $2,469,487 |  |  | $1,100,028 |  |  | $903,624 |  |  | $54,462 |  |  | $195,011 |  |  | $20,028 |  |  | $2,542,584 |
2022 |  | Co-PEO 1 |  | $3,991,434 |  |  | $2,100,000 |  |  | $2,052,649 |  | ** | $318,514 |  |  | — |  |  | $145,599 |  |  | $4,408,196 |
|  | Co-PEO 2 |  | $3,981,772 |  |  | $2,100,000 |  |  | $2,052,649 |  | ** | — |  |  | — |  |  | $464,113 |  |  | $4,398,534 |
|  | Non-PEO NEOs* |  | $1,668,541 |  |  | $615,625 |  |  | $601,434 |  | ** | $79,545 |  |  | — |  |  | $29,283 |  |  | $1,763,178 |
|  | * As an average.
|  | ** Reflects corrections to amounts previously reported for the 2022 year-end fair value of stock awards granted during 2022 that were outstanding and unvested as of the end of 2022.
[3] | The amounts set out in these columns (i) represent the amounts of “compensation actually paid” to the PEO, or each Co-PEO, as computed in accordance with Item 402(v) of Regulation S-K, and (ii) do not reflect the actual amounts of compensation earned by or paid to the PEO, or each Co-PEO, during the applicable fiscal year.
[4] | The named executive officers for the 2022 fiscal year included Thomas S. Gayner, as Co-PEO 1, and Richard R. Whitt, III, as Co-PEO 2, and Michael R. Heaton, Jeremy A. Noble, Robert C. Cox and Richard R. Grinnan as the non-PEO named executive officers.
[5] | The named executive officers for the 2021 fiscal year included Thomas S. Gayner, as Co-PEO 1, and Richard R. Whitt, III, as Co-PEO 2, and Michael R. Heaton, Jeremy A. Noble, Robert C. Cox and Bradley J. Kiscaden as the non-PEO named executive officers.
[6] | The named executive officers for the 2020 fiscal year included Thomas S. Gayner, as Co-PEO 1, and Richard R. Whitt, III, as Co-PEO 2, and Jeremy A. Noble, Robert C. Cox, Bradley J. Kiscaden and Richard R. Grinnan as the non-PEO named executive officers.
[7] | The amounts set out in this column (i) represent the average amounts of “compensation actually paid” to the non-PEO named executed officers, as computed in accordance with Item 402(v) of Regulation S-K, and (ii) do not reflect the actual average amounts of compensation earned by or paid to the non-PEO named executive officers during the applicable fiscal year.
[8] | Dow Jones U.S. Property & Casualty Insurance Companies Index.
[9] | Amounts are as disclosed in the Pay Versus Performance Table in the Company’s 2023 Proxy Statement. Due to a restatement as a result of the required adoption of Financial Accounting Standards Board (FASB) Accounting Standards Update (ASU) No. 2018-12, Financial Services—Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts effective January 1, 2023, net income for 2022 and 2021 has been restated to $(103,357,000) and $2,445,867,000, respectively.
[10] | The term CAGR means compound annual growth rate.
[11] | These Company-selected financial performance measures represent the most important financial performance measures used by the Company and were weighted equally to link compensation actually paid to the Company’s named executed officers (excluding Mr. Costanzo and Ms. Gendron), for the most recently completed fiscal year, to the Company’s performance. See “Cash Incentive Compensation for Brian J. Costanzo” and “Compensation for Teresa S. Gendron” for a discussion of performance measures for Mr. Costanzo and Ms. Gendron, respectively.

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Name: | ecd_AdjToCompAxis=mkl_TheChangeAsOfTheEndOfTheCoveredFiscalYearInFairValueOfAnyStockAwardsGrantedInAnyPriorFiscalYearThatAreOutstandingAndUnvestedAsOfTheEndOfTheCoveredFiscalYearMember
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Data Type: | na
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X
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Name: | ecd_AdjToCompAxis=mkl_ForStockAwardsThatAreGrantedAndVestInTheSameCoveredFiscalYearTheFairValueAsOfTheVestingDateMember
Namespace Prefix: |
Data Type: | na
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X
- Details
Name: | ecd_AdjToCompAxis=mkl_TheChangeAsOfTheVestingDateInFairValueOfAnyStockAwardsGrantedInAnyPriorFiscalYearForWhichAllVestingConditionsWereSatisfiedAtTheEndOfOrDuringTheCoveredFiscalYearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
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X
- Details
Name: | ecd_ExecutiveCategoryAxis=ecd_NonPeoNeoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |