Markel (MKL) 10-Q 2 Aug 22 2022 Q2 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	6 Months Ended
	Jun. 30, 2022	Jul. 26, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2022
Document Transition Report	false
Entity File Number	001-15811
Entity Registrant Name	MARKEL CORPORATION
Entity Incorporation, State or Country Code	VA
Entity Tax Identification Number	54-1959284
Entity Address, Address Line One	4521 Highwoods Parkway
Entity Address, City or Town	Glen Allen
Entity Address, State or Province	VA
Entity Address, Postal Zip Code	23060-6148
City Area Code	804
Local Phone Number	747-0136
Title of 12(b) Security	Common Stock, no par value
Trading Symbol	MKL
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		13,525,410
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Entity Central Index Key	0001096343
Current Fiscal Year End Date	--12-31

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Assets [Abstract]
Fixed maturities, available-for-sale (amortized cost of $12,532,957 in 2022 and $12,061,467 in 2021)	$ 11,943,894	$ 12,587,305
Equity securities (cost of $2,939,975 in 2022 and $2,867,899 in 2021)	7,170,001	9,023,927
Short-term investments, available-for-sale (estimated fair value approximates cost)	2,055,534	1,799,988
Total Investments	21,169,429	23,411,220
Cash and cash equivalents	3,698,854	3,978,490
Restricted cash and cash equivalents	1,212,463	902,457
Receivables	3,128,706	2,413,938
Reinsurance recoverables	7,315,657	7,293,555
Deferred policy acquisition costs	954,521	794,145
Prepaid reinsurance premiums	2,123,256	1,798,571
Goodwill	2,769,729	2,899,140
Intangible assets	1,729,174	1,822,486
Other assets	3,844,984	3,163,094
Total Assets	47,946,773	48,477,096
Liabilities and Equity [Abstract]
Unpaid losses and loss adjustment expenses	19,062,760	18,178,894
Life and annuity benefits	777,726	902,980
Unearned premiums	6,336,362	5,383,619
Payables to insurance and reinsurance companies	703,481	616,665
Senior long-term debt and other debt (estimated fair value of $4,199,000 in 2022 and $5,017,000 in 2021)	4,502,237	4,361,266
Other liabilities	3,301,497	3,832,084
Total Liabilities	34,684,063	33,275,508
Redeemable noncontrolling interests	495,378	461,378
Commitments and contingencies
Shareholders' equity:
Preferred Stock	591,891	591,891
Common stock	3,478,153	3,441,079
Retained earnings	9,289,820	10,446,763
Accumulated other comprehensive income (loss)	(603,657)	237,617
Total Shareholders' Equity	12,756,207	14,717,350
Noncontrolling interests	11,125	22,860
Total Equity	12,767,332	14,740,210
Total Liabilities and Equity	$ 47,946,773	$ 48,477,096

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Fixed maturities, available-for-sale, amortized cost	$ 12,532,957	$ 12,061,467
Equity securities, cost	2,939,975	2,867,899
Senior long-term debt and other debt, fair value	$ 4,199,000	$ 5,017,000

Consolidated Statements Of Inco

Consolidated Statements Of Income (Loss) And Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022		Jun. 30, 2021		Jun. 30, 2022		Jun. 30, 2021
OPERATING REVENUES
Earned premiums	$ 1,833,104		$ 1,568,037		$ 3,592,874		$ 3,065,732
Net investment income	93,658		96,261		166,392		192,831
Net investment gains (losses)	(1,554,643)		674,753		(1,913,042)		1,201,624
Products revenues	776,959		592,601		1,258,580		921,433
Services and other revenues	643,129		569,120		1,293,639		1,019,346
Total Operating Revenues	1,792,207		3,500,772		4,398,443		6,400,966
OPERATING EXPENSES
Losses and loss adjustment expenses	1,058,810		814,955		2,031,182		1,694,873
Underwriting, acquisition and insurance expenses	609,469		548,364		1,199,834		1,075,107
Products expenses	697,718		502,202		1,145,537		798,728
Services and other expenses	559,858		516,251		1,151,634		928,348
Amortization of intangible assets	45,523	[1]	39,729	[2]	91,572	[3]	79,282	[4]
Total Operating Expenses	2,971,378		2,421,501		5,619,759		4,576,338
Operating Income (Loss)	(1,179,171)		1,079,271		(1,221,316)		1,824,628
Interest expense	(50,050)		(46,568)		(99,742)		(88,957)
Net foreign exchange gains (losses)	106,732		(12,257)		130,226		12,827
Income (Loss) Before Income Taxes	(1,122,489)		1,020,446		(1,190,832)		1,748,498
Income tax (expense) benefit	239,102		(217,112)		257,531		(365,483)
Net Income (Loss)	(883,387)		803,334		(933,301)		1,383,015
Net income attributable to noncontrolling interests	(32,972)		(11,224)		(35,901)		(17,211)
Net Income (Loss) to Shareholders	(916,359)		792,110		(969,202)		1,365,804
Preferred stock dividends	(18,000)		(18,000)		(18,000)		(18,000)
Net Income (Loss) to Common Stockholders	(934,359)		774,110		(987,202)		1,347,804
OTHER COMPREHENSIVE INCOME (LOSS)
Net holding gains (losses) arising during the period	(362,392)		55,935		(838,910)		(158,441)
Reclassification adjustments for net gains (losses) included in net income (loss)	1,261		(3,943)		1,698		(4,031)
Change in net unrealized gains (losses) on available-for-sale investments, net of taxes	(361,131)		51,992		(837,212)		(162,472)
Change in foreign currency translation adjustments, net of taxes	(4,275)		4,915		(5,523)		4,107
Change in net actuarial pension loss, net of taxes	373		654		1,505		1,246
Total Other Comprehensive Income (Loss)	(365,033)		57,561		(841,230)		(157,119)
Comprehensive Income (Loss)	(1,248,420)		860,895		(1,774,531)		1,225,896
Comprehensive income attributable to noncontrolling interests	(33,029)		(11,241)		(35,945)		(17,245)
Comprehensive Income (Loss) to Shareholders	$ (1,281,449)		$ 849,654		$ (1,810,476)		$ 1,208,651
NET INCOME (LOSS) PER COMMON SHARE
Basic	$ (69.19)		$ 57.12		$ (75.68)		$ 99.19
Diluted	$ (69.19)	[5]	$ 57.02		$ (75.68)	[5]	$ 99.03
[1]Segment profit for the Markel Ventures segment includes amortization of intangible assets attributable to Markel Ventures. Amortization of intangible assets is not allocated to the Company's Insurance and Reinsurance segments.[2]Segment profit for the Markel Ventures segment includes amortization of intangible assets attributable to Markel Ventures. Amortization of intangible assets is not allocated to the Company's Insurance and Reinsurance segments.[3]Segment profit for the Markel Ventures segment includes amortization of intangible assets attributable to Markel Ventures. Amortization of intangible assets is not allocated to the Company's Insurance and Reinsurance segments.[4]Segment profit for the Markel Ventures segment includes amortization of intangible assets attributable to Markel Ventures. Amortization of intangible assets is not allocated to the Company's Insurance and Reinsurance segments.[5]The impact of 31 thousand and 29 thousand shares from restricted stock units and restricted stock was excluded from the computation of diluted net loss per common share for the quarter and six months ended June 30, 2022, respectively, because the effect would have been anti-dilutive.

Consolidated Statements Of Chan

Consolidated Statements Of Changes In Equity - USD ($) $ in Thousands	Total	Total Equity [Member]	Total Shareholders' Equity [Member]	Preferred Stock [Member]	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]	Redeemable Noncontrolling Interests [Member]	Velocity [Member] Total Equity [Member]	Velocity [Member] Noncontrolling Interests [Member]	Metromont LLC [Member] Redeemable Noncontrolling Interests [Member]
Balance at Dec. 31, 2020		$ 12,814,681	$ 12,799,789	$ 591,891	$ 3,428,340	$ 8,195,182	$ 584,376	$ 14,892
Balance, redeemable noncontrolling interests at Dec. 31, 2020									$ 245,642
Net Income (Loss)	$ 1,383,015	1,373,206	1,365,804			1,365,804	0	7,402	9,809
Other comprehensive income (loss)	(157,119)	(157,153)	(157,153)			0	(157,153)	0	34
Comprehensive Income (Loss)	1,225,896	1,216,053	1,208,651					7,402	9,843
Repurchase of common stock		(60,826)	(60,826)	0	0	(60,826)	0	0	0
Preferred stock dividends		(18,000)	(18,000)	0	0	(18,000)	0	0	0
Restricted stock units expensed		23,602	23,602	0	23,602	0	0	0	0
Adjustment of redeemable noncontrolling interests		21,623	21,623	0	0	21,623	0	0	(21,623)
Purchase of noncontrolling interest		(531)	(531)	0	(531)	0	0	0	(147)
Other		1,447	663	0	557	106	0	784	(5,314)
Balance at Jun. 30, 2021		14,020,351	13,997,273	591,891	3,451,968	9,526,191	427,223	23,078
Balance, redeemable noncontrolling interests at Jun. 30, 2021									228,401
Balance at Mar. 31, 2021		13,207,466	13,186,246	591,891	3,447,614	8,777,062	369,679	21,220
Balance, redeemable noncontrolling interests at Mar. 31, 2021									234,654
Net Income (Loss)	803,334	792,837	792,110			792,110	0	727	10,497
Other comprehensive income (loss)	57,561	57,544	57,544			0	57,544	0	17
Comprehensive Income (Loss)	860,895	850,381	849,654					727	10,514
Repurchase of common stock		(38,803)	(38,803)	0	0	(38,803)	0	0	0
Preferred stock dividends	(18,000)	(18,000)	(18,000)	0	0	(18,000)	0	0	0
Restricted stock units expensed		4,442	4,442	0	4,442	0	0	0	0
Adjustment of redeemable noncontrolling interests		13,717	13,717	0	0	13,717	0	0	(13,717)
Other		1,148	17	0	(88)	105	0	1,131	(3,050)
Balance at Jun. 30, 2021		14,020,351	13,997,273	591,891	3,451,968	9,526,191	427,223	23,078
Balance, redeemable noncontrolling interests at Jun. 30, 2021									228,401
Balance at Dec. 31, 2021	14,740,210	14,740,210	14,717,350	591,891	3,441,079	10,446,763	237,617	22,860
Balance, redeemable noncontrolling interests at Dec. 31, 2021	461,378								461,378
Net Income (Loss)	(933,301)	(943,786)	(969,202)			(969,202)	0	25,416	10,485
Other comprehensive income (loss)	(841,230)	(841,274)	(841,274)			0	(841,274)	0	44
Comprehensive Income (Loss)	(1,774,531)	(1,785,060)	(1,810,476)					25,416	10,529
Repurchase of common stock		(126,291)	(126,291)	0	0	(126,291)	0	0	0
Preferred stock dividends		(18,000)	(18,000)	0	0	(18,000)	0	0	0
Restricted stock units expensed		32,870	32,870	0	32,870	0	0	0	0
Adjustment of redeemable noncontrolling interests		(44,438)	(44,438)	0	0	(44,438)	0	0	44,438
Acquisitions		0	0	0	0	0	0	0				$ (18,681)
Dispositions			0	0	0	0	0		0	$ (22,059)	$ (22,059)
Redemption of Markel CATCo Re noncontrolling interests		(22,261)	0	0	0	0	0	(22,261)	0
Other		12,361	5,192	0	4,204	988	0	7,169	(2,286)
Balance at Jun. 30, 2022	12,767,332	12,767,332	12,756,207	591,891	3,478,153	9,289,820	(603,657)	11,125
Balance, redeemable noncontrolling interests at Jun. 30, 2022	495,378								495,378
Balance at Mar. 31, 2022		14,106,732	14,101,178	591,891	3,469,449	10,278,405	(238,567)	5,554
Balance, redeemable noncontrolling interests at Mar. 31, 2022									480,351
Net Income (Loss)	(883,387)	(890,370)	(916,359)			(916,359)	0	25,989	6,983
Other comprehensive income (loss)	(365,033)	(365,090)	(365,090)			0	(365,090)	0	57
Comprehensive Income (Loss)	(1,248,420)	(1,255,460)	(1,281,449)					25,989	7,040
Repurchase of common stock		(46,995)	(46,995)	0	0	(46,995)	0	0	0
Preferred stock dividends	(18,000)	(18,000)	(18,000)	0	0	(18,000)	0	0	0
Restricted stock units expensed		4,406	4,406	0	4,406	0	0	0	0
Adjustment of redeemable noncontrolling interests		(7,498)	(7,498)	0	0	(7,498)	0	0	7,498
Redemption of Markel CATCo Re noncontrolling interests		(22,261)	0	0	0	0	0	(22,261)	0
Other		6,408	4,565	0	4,298	267	0	1,843	489
Balance at Jun. 30, 2022	12,767,332	$ 12,767,332	$ 12,756,207	$ 591,891	$ 3,478,153	$ 9,289,820	$ (603,657)	$ 11,125
Balance, redeemable noncontrolling interests at Jun. 30, 2022	$ 495,378								$ 495,378

Condensed Consolidated Statemen

Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
OPERATING ACTIVITIES
Net income (loss)	$ (933,301)	$ 1,383,015
Adjustments to reconcile net income (loss) to net cash provided by operating activities	1,854,290	(569,843)
Net Cash Provided By Operating Activities	920,989	813,172
INVESTING ACTIVITIES
Proceeds from sales, maturities, calls and prepayments of fixed maturity securities	370,028	294,552
Cost of fixed maturity securities purchased	(889,888)	(1,315,010)
Proceeds from sales of equity securities	146,116	115,312
Cost of equity securities purchased	(209,576)	(95,298)
Net change in short-term investments	(256,698)	(1,227,644)
Additions to property and equipment	(110,544)	(55,738)
Consolidation of Markel CATCo Re, net	629,955	0
Distributions to Markel CATCo Re noncontrolling interests for buyout transaction	(169,380)	0
Proceeds from sale of business, net	109,505	39,585
Other	(22,879)	6,902
Net Cash Used By Investing Activities	(403,361)	(2,237,339)
FINANCING ACTIVITIES
Additions to senior long-term debt and other debt	529,051	893,575
Repayments of senior long-term debt and other debt	(387,165)	(217,348)
Advance funding for repayment of senior long-term debt	(350,000)	0
Repurchases of common stock	(126,291)	(60,826)
Dividends paid on preferred stock	(18,000)	(18,000)
Other	(34,304)	(33,120)
Net Cash Provided (Used) By Financing Activities	(386,709)	564,281
Effect of foreign currency rate changes on cash, cash equivalents, restricted cash and restricted cash equivalents	(100,549)	(4,945)
Increase (decrease) in cash, cash equivalents, restricted cash and restricted cash equivalents	30,370	(864,831)
Cash, cash equivalents, restricted cash and restricted cash equivalents at beginning of period	4,880,947	5,216,649
Cash, cash equivalents, restricted cash and restricted cash equivalents at end of period	$ 4,911,317	$ 4,351,818

Summary Of Significant Accounti

Summary Of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2022
Accounting Policies [Abstract]
Summary Of Significant Accounting Policies	Summary of Significant Accounting Policies Markel Corporation is a diverse financial holding company serving a variety of niche markets. Markel Corporation's principal business markets and underwrites specialty insurance products. Through its wholly owned subsidiary, Markel Ventures, Inc. (Markel Ventures), Markel Corporation also owns controlling interests in various businesses that operate outside of the specialty insurance marketplace. See note 2 for details regarding reportable segments. a) Basis of Presentation. The consolidated balance sheet as of June 30, 2022 and the related consolidated statements of income (loss) and comprehensive income (loss) and changes in equity for the quarters and six months ended June 30, 2022 and 2021, and the condensed consolidated statements of cash flows for the six months ended June 30, 2022 and 2021 are unaudited. In the opinion of management, all adjustments necessary for fair presentation of such consolidated financial statements have been included. Except for the adjustment described in note 15, such adjustments consist only of normal, recurring items. Interim results are not necessarily indicative of results of operations for the entire year. The consolidated balance sheet as of December 31, 2021 was derived from Markel Corporation's audited annual consolidated financial statements. The accompanying consolidated financial statements have been prepared in accordance with United States (U.S.) generally accepted accounting principles (GAAP) and include the accounts of Markel Corporation and its consolidated subsidiaries, as well as any variable interest entities (VIEs) that meet the requirements for consolidation (the Company). All significant intercompany balances and transactions have been eliminated in consolidation. The Company consolidates the results of its Markel Ventures subsidiaries on a one-month lag, with the exception of significant transactions or events that occur during the intervening period. Certain prior period amounts have been reclassified to conform to the current period presentation. 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. Actual results may differ materially from the estimates and assumptions used in preparing the consolidated financial statements. The consolidated financial statements and notes are presented as permitted by Form 10-Q and do not contain certain information included in the Company's annual consolidated financial statements and notes. For a more complete description of the Company's business and accounting policies, readers are urged to review the Company's 2021 Annual Report on Form 10-K, as well as note 15 for details regarding a change to the Company's policy for accounting for deferred policy acquisition costs. b) Recent Accounting Pronouncements Accounting Standards Not Yet Adopted In August 2018, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2018-12, Financial Services—Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts. The FASB subsequently issued several ASUs as amendments to ASU No. 2018-12. The standard requires insurance companies with long duration contracts to: (1) review and, if there is a change, update the assumptions used to measure expected cash flows at least annually; (2) update the discount rate assumption at each reporting date; and (3) enhance disclosures, which includes (i) providing information about significant inputs, judgments and assumptions used to measure the liability and (ii) expanding the quantitative disclosures. ASU No. 2018-12 becomes effective for the Company during the first quarter of 2023 and will be applied using a modified retrospective approach that requires restatement of prior periods presented, including a cumulative adjustment to beginning accumulated other comprehensive income for the earliest period presented. The standard will, among other things, impact the discount rate used in estimating reserves for the Company's life and annuity reinsurance portfolio, which is in runoff. Currently, the discount rate assumption is locked-in for the life of the contracts, unless there is a loss recognition event. The Company is currently evaluating ASU No. 2018-12 to determine the impact that adopting this standard will have on its consolidated financial statements. In October 2021, the FASB issued ASU No. 2021-08, Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customer s, which becomes effective for the Company during the first quarter of 2023. ASU No. 2021-08 requires contract assets and liabilities accounted for under FASB Accounting Standards Codification (ASC) 606, Revenue from Contracts with Customers , to be recorded at the acquisition date as if the acquirer entered into those contracts itself on the contract inception dates, rather than at fair value. At adoption, ASU No. 2021-08 will not impact the Company's financial position, results of operations or cash flows, but prospectively, this ASU will impact amounts recorded by the Company for assets acquired and liabilities assumed in conjunction with certain acquisitions.

Segment Reporting Disclosures

Segment Reporting Disclosures	6 Months Ended
	Jun. 30, 2022
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Segment Reporting Disclosures	Segment Reporting Disclosures The chief operating decision maker reviews the Company's ongoing underwriting operations on a global basis in the following two segments: Insurance and Reinsurance. In determining how to allocate resources and assess the performance of the Company's underwriting results, management considers many factors, including the nature of the insurance product sold, the type of account written and the type of customer served. The Insurance segment includes all direct business and facultative placements written on a risk-bearing basis within the Company's underwriting operations. The Reinsurance segment includes all treaty reinsurance written on a risk-bearing basis within the Company's underwriting operations. All investing activities related to the Company's insurance operations are included in the Investing segment. The chief operating decision maker reviews and assesses Markel Ventures' performance in the aggregate, as a single operating segment. The Markel Ventures segment primarily consists of controlling interests in a diverse portfolio of businesses that operate in various industries. The Company's other operations primarily consist of the results of the Company's insurance-linked securities operations and program services business. Other operations also include results for lines of business discontinued prior to, or in conjunction with, acquisitions, including development on asbestos and environmental loss reserves and results attributable to the run-off of life and annuity reinsurance business, which are monitored separately from the Company's ongoing underwriting operations. For purposes of segment reporting, none of these other operations are considered to be reportable segments. Segment profit for each of the Company's underwriting segments is measured by underwriting profit. The property and casualty insurance industry commonly defines underwriting profit as earned premiums net of losses and loss adjustment expenses and underwriting, acquisition and insurance expenses. Underwriting profit does not replace operating income or net income computed in accordance with U.S. GAAP as a measure of profitability. Underwriting profit or loss provides a basis for management to evaluate the Company's underwriting performance. Segment profit for the Company's underwriting segments may also include other revenues and expenses that are attributable to the Company's underwriting operations that are not captured in underwriting profit. Segment profit for the Investing segment is measured by net investment income and net investment gains. Segment profit for the Markel Ventures segment is measured by operating income. For management reporting purposes, the Company allocates assets to its underwriting operations and to its Investing and Markel Ventures segments and certain of its other operations, including its insurance-linked securities and program services operations. Underwriting assets include assets attributed to the Company's Insurance and Reinsurance segments, discontinued underwriting lines of business, as well as assets that are not specifically allocated to the Company's other operations. Generally, the Company manages its underwriting assets in the aggregate and therefore does not allocate assets to individual underwriting segments. a) The following tables summarize the Company's segment disclosures. Quarter Ended June 30, 2022 (dollars in thousands) Insurance Reinsurance Investing Markel Ventures (1) Other (2) Consolidated Gross premium volume $ 2,237,158 $ 289,056 $ — $ — $ 753,835 $ 3,280,049 Net written premiums 1,828,162 273,838 — — (2,205) 2,099,795 Earned premiums 1,570,001 264,154 — — (1,051) 1,833,104 Losses and loss adjustment expenses: Current accident year (919,283) (165,932) — — — (1,085,215) Prior accident years 43,693 (13,577) — — (3,711) 26,405 Underwriting, acquisition and insurance expenses: Amortization of policy acquisition costs (323,826) (69,125) — — (32) (392,983) Other underwriting expenses (204,171) (11,681) — — (634) (216,486) Underwriting profit (loss) 166,414 3,839 — — (5,428) 164,825 Net investment income — — 93,558 100 — 93,658 Net investment losses — — (1,554,643) — — (1,554,643) Products revenues — — — 776,959 — 776,959 Services and other revenues — — — 584,339 58,790 643,129 Products expenses — — — (697,718) — (697,718) Services and other expenses — — — (536,057) (23,801) (559,858) Amortization of intangible assets (3) — — — (20,577) (24,946) (45,523) Segment profit (loss) $ 166,414 $ 3,839 $ (1,461,085) $ 107,046 $ 4,615 $ (1,179,171) Interest expense (50,050) Net foreign exchange gains 106,732 Loss before income taxes $ (1,122,489) U.S. GAAP combined ratio (4) 89 % 99 % NM (5) 91 % (1) Products expenses and services and other expenses for the Markel Ventures segment include depreciation expense of $26.5 million for the quarter ended June 30, 2022. (2) Other represents the total profit (loss) attributable to the Company's operations that are not included in a reportable segment as well as any amortization of intangible assets that is not allocated to a reportable segment. Amortization of intangible assets attributable to the Company's underwriting segments was $9.6 million for the quarter ended June 30, 2022, however, the Company does not allocate amortization of intangible assets between the Insurance and Reinsurance segments. (3) Segment profit for the Markel Ventures segment includes amortization of intangible assets attributable to Markel Ventures. Amortization of intangible assets is not allocated to the Company's Insurance and Reinsurance segments. (4) The U.S. GAAP combined ratio is a measure of underwriting performance and represents the relationship of incurred losses, loss adjustment expenses and underwriting, acquisition and insurance expenses to earned premiums. (5) NM - Ratio is not meaningful Quarter Ended June 30, 2021 (dollars in thousands) Insurance Reinsurance Investing Markel Ventures (1) Other (2) Consolidated Gross premium volume $ 1,821,374 $ 279,444 $ — $ — $ 783,195 $ 2,884,013 Net written premiums 1,494,443 257,355 — — (347) 1,751,451 Earned premiums 1,303,562 264,982 — — (507) 1,568,037 Losses and loss adjustment expenses: Current accident year (783,306) (166,853) — — — (950,159) Prior accident years 154,526 (21,741) — — 2,419 135,204 Underwriting, acquisition and insurance expenses: Amortization of policy acquisition costs (264,823) (67,986) — — — (332,809) Other underwriting expenses (204,622) (13,414) — — 2,481 (215,555) Underwriting profit (loss) 205,337 (5,012) — — 4,393 204,718 Net investment income — — 96,259 2 — 96,261 Net investment gains — — 674,753 — — 674,753 Products revenues — — — 592,601 — 592,601 Services and other revenues — — — 482,903 86,217 569,120 Products expenses — — — (502,202) — (502,202) Services and other expenses — 109 — (450,781) (65,579) (516,251) Amortization of intangible assets (3) — — — (13,858) (25,871) (39,729) Segment profit (loss) $ 205,337 $ (4,903) $ 771,012 $ 108,665 $ (840) $ 1,079,271 Interest expense (46,568) Net foreign exchange losses (12,257) Income before income taxes $ 1,020,446 U.S. GAAP combined ratio (4) 84 % 102 % NM (5) 87 % (1) Products expenses and services and other expenses for the Markel Ventures segment include depreciation expense of $15.8 million for the quarter ended June 30, 2021. (2) Other represents the total profit (loss) attributable to the Company's operations that are not included in a reportable segment as well as any amortization of intangible assets that is not allocated to a reportable segment. Amortization of intangible assets attributable to the Company's underwriting segments was $10.4 million for the quarter ended June 30, 2021, however, the Company does not allocate amortization of intangible assets between the Insurance and Reinsurance segments. (3) Segment profit for the Markel Ventures segment includes amortization of intangible assets attributable to Markel Ventures. Amortization of intangible assets is not allocated to the Company's Insurance and Reinsurance segments. (4) The U.S. GAAP combined ratio is a measure of underwriting performance and represents the relationship of incurred losses, loss adjustment expenses and underwriting, acquisition and insurance expenses to earned premiums. (5) NM - Ratio is not meaningful Six Months Ended June 30, 2022 (dollars in thousands) Insurance Reinsurance Investing Markel Ventures (1) Other (2) Consolidated Gross premium volume $ 4,180,464 $ 865,372 $ — $ — $ 1,632,500 $ 6,678,336 Net written premiums 3,439,182 829,058 — — (3,711) 4,264,529 Earned premiums 3,047,149 548,121 — — (2,396) 3,592,874 Losses and loss adjustment expenses: Current accident year (1,805,520) (348,390) — — — (2,153,910) Prior accident years 142,333 (15,660) — — (3,945) 122,728 Underwriting, acquisition and insurance expenses: Amortization of policy acquisition costs (634,232) (140,879) — — (32) (775,143) Other underwriting expenses (395,822) (26,070) — — (2,799) (424,691) Underwriting profit (loss) 353,908 17,122 — — (9,172) 361,858 Net investment income — — 166,285 107 — 166,392 Net investment losses — — (1,913,042) — — (1,913,042) Products revenues — — — 1,258,580 — 1,258,580 Services and other revenues — — — 1,053,103 240,536 1,293,639 Products expenses — — — (1,145,537) — (1,145,537) Services and other expenses — — — (967,960) (183,674) (1,151,634) Amortization of intangible assets (3) — — — (41,510) (50,062) (91,572) Segment profit (loss) $ 353,908 $ 17,122 $ (1,746,757) $ 156,783 $ (2,372) $ (1,221,316) Interest expense (99,742) Net foreign exchange gains 130,226 Loss before income taxes $ (1,190,832) U.S. GAAP combined ratio (4) 88 % 97 % NM (5) 90 % (1) Products expenses and services and other expenses for the Markel Ventures segment include depreciation expense of $51.6 million for the six months ended June 30, 2022. (2) Other represents the total profit (loss) attributable to the Company's operations that are not included in a reportable segment as well as any amortization of intangible assets that is not allocated to a reportable segment. Amortization of intangible assets attributable to the Company's underwriting segments was $19.4 million for the six months ended June 30, 2022, however, the Company does not allocate amortization of intangible assets between the Insurance and Reinsurance segments. (3) Segment profit for the Markel Ventures segment includes amortization of intangible assets attributable to Markel Ventures. Amortization of intangible assets is not allocated to the Company's Insurance and Reinsurance segments. (4) The U.S. GAAP combined ratio is a measure of underwriting performance and represents the relationship of incurred losses, loss adjustment expenses and underwriting, acquisition and insurance expenses to earned premiums. (5) NM - Ratio is not meaningful Six Months Ended June 30, 2021 (dollars in thousands) Insurance Reinsurance Investing Markel Ventures (1) Other (2) Consolidated Gross premium volume $ 3,459,701 $ 811,962 $ — $ — $ 1,417,202 $ 5,688,865 Net written premiums 2,881,873 751,440 — — (792) 3,632,521 Earned premiums 2,547,589 519,069 — — (926) 3,065,732 Losses and loss adjustment expenses: Current accident year (1,581,553) (339,354) — — — (1,920,907) Prior accident years 273,590 (50,396) — — 2,840 226,034 Underwriting, acquisition and insurance expenses: Amortization of policy acquisition costs (525,422) (129,974) — — — (655,396) Other underwriting expenses (391,919) (27,575) — — (217) (419,711) Underwriting profit (loss) 322,285 (28,230) — — 1,697 295,752 Net investment income — — 192,826 5 — 192,831 Net investment gains — — 1,201,624 — — 1,201,624 Products revenues — — — 921,433 — 921,433 Services and other revenues — — — 860,670 158,676 1,019,346 Products expenses — — — (798,728) — (798,728) Services and other expenses — 109 — (795,689) (132,768) (928,348) Amortization of intangible assets (3) — — — (27,563) (51,719) (79,282) Segment profit (loss) $ 322,285 $ (28,121) $ 1,394,450 $ 160,128 $ (24,114) $ 1,824,628 Interest expense (88,957) Net foreign exchange gains 12,827 Income before income taxes $ 1,748,498 U.S. GAAP combined ratio (4) 87 % 105 % NM (5) 90 % (1) Products expenses and services and other expenses for the Markel Ventures segment include depreciation expense of $31.8 million for the six months ended June 30, 2021. (2) Other represents the total profit (loss) attributable to the Company's operations that are not included in a reportable segment as well as any amortization of intangible assets that is not allocated to a reportable segment. Amortization of intangible assets attributable to the Company's underwriting segments was $20.8 million for the six months ended June 30, 2021, however, the Company does not allocate amortization of intangible assets between the Insurance and Reinsurance segments. (3) Segment profit for the Markel Ventures segment includes amortization of intangible assets attributable to Markel Ventures. Amortization of intangible assets is not allocated to the Company's Insurance and Reinsurance segments. (4) The U.S. GAAP combined ratio is a measure of underwriting performance and represents the relationship of incurred losses, loss adjustment expenses and underwriting, acquisition and insurance expenses to earned premiums. (5) NM - Ratio is not meaningful b) The following table reconciles segment assets to the Company's consolidated balance sheets. (dollars in thousands) June 30, 2022 December 31, 2021 Segment assets: Investing $ 25,616,813 $ 28,277,801 Underwriting 9,086,833 8,111,316 Markel Ventures 5,195,988 4,958,279 Total segment assets 39,899,634 41,347,396 Other operations 8,047,139 7,129,700 Total assets $ 47,946,773 $ 48,477,096

Acquisitions and Dispositions

Acquisitions and Dispositions	6 Months Ended
	Jun. 30, 2022
Business Combinations, Asset Acquisition and Disposition [Abstract]
Acquisitions and Dispositions	Acquisitions and Dispositions Velocity In February 2022, the Company sold the majority of its controlling interest in its Velocity managing general agent companies (Velocity) for total cash consideration of $181.3 million, which resulted in a gain of $107.3 million that was included in services and other revenues. Velocity provides risk origination services for the Company's Nephila insurance-linked securities fund management operations, as well as for third parties. The Company retained a minority interest in Velocity that was recorded at fair value as of the transaction date ($47.4 million) and is accounted for under the equity method. Metromont LLC In December 2021, the Company acquired 51% of Metromont LLC (Metromont), a precast concrete manufacturer and concrete building solutions provider for commercial projects. Under the terms of the acquisition agreement, the Company has the option to acquire the remaining equity interests and the remaining equity holders have the option to sell their interests to the Company in the future. The redemption value of the remaining equity interests is generally based on Metromont's earnings in specified periods preceding the redemption date. Total consideration for the transaction was $282.3 million, all of which was cash. As of December 31, 2021, the purchase price was preliminarily allocated to the acquired assets and liabilities based on estimated fair value at the acquisition date, which was subsequently updated during the first quarter of 2022. During the first quarter of 2022, the Company decreased the allocation to goodwill by $18.7 million with an offsetting decrease to redeemable noncontrolling interests of $18.7 million, resulting in a preliminary purchase price allocation that reflected goodwill of $200.6 million, intangible assets of $143.9 million and redeemable noncontrolling interests of $251.2 million. Goodwill is primarily attributable to expected future earnings and cash flow potential of Metromont, and it is expected to be deductible for income tax purposes. Results attributable to Metromont are included in the Company's Markel Ventures segment. The Company has not completed the process of determining the fair value of the assets acquired and liabilities assumed. These valuations are required to be completed within 12 months from the acquisition date. As a result, the fair value recorded for these items is a provisional estimate and is subject to adjustment. Once completed, any adjustments resulting from the valuations may impact the individual amounts recorded for assets acquired and liabilities assumed, as well as the residual goodwill. Buckner HeavyLift Cranes In August 2021, the Company acquired 90% of the holding company for the Buckner HeavyLift Cranes companies (Buckner), a provider of crane rental services for large commercial contractors. Under the terms of the acquisition agreement, the Company has the option to acquire the remaining equity interests and the remaining equity holders have the option to sell their interests to the Company in the future. The redemption value of the remaining equity interests is generally based on Buckner's earnings in specified periods preceding the redemption dates. Total consideration for the transaction was $237.9 million, all of which was cash. The purchase price was preliminarily allocated to the acquired assets and liabilities of Buckner based on estimated fair value at the acquisition date. The Company recognized goodwill of $74.5 million, intangible assets of $60.0 million and fixed assets of $332.6 million, primarily related to cranes. Goodwill is primarily attributable to expected future earnings and cash flow potential of Buckner, and it is not expected to be deductible for income tax purposes. Intangible assets include $50.0 million of customer relationships and $10.0 million of trade names, which are expected to be amortized over 6 years and 15 years, respectively. Additionally, the Company assumed long-term debt of $165.1 million and recognized redeemable noncontrolling interests of $26.4 million. Results attributable to Buckner are included in the Company's Markel Ventures segment. The Company has not completed the process of determining the fair value of the assets acquired and liabilities assumed. These valuations are required to be completed within 12 months from the acquisition date. As a result, the fair value recorded for these items is a provisional estimate and is subject to adjustment. Once completed, any adjustments resulting from the valuations may impact the individual amounts recorded for assets acquired and liabilities assumed, as well as the residual goodwill.

Investments

Investments	6 Months Ended
	Jun. 30, 2022
Investments, Debt and Equity Securities [Abstract]
Investments	Investments a) The following tables summarize the Company's available-for-sale investments. Commercial and residential mortgage-backed securities include securities issued by U.S. government-sponsored enterprises and U.S. government agencies. The net unrealized holding gains (losses) in the tables below are presented before taxes and any reserve deficiency adjustments for life and annuity benefit reserves. See note 9. June 30, 2022 (dollars in thousands) Amortized Gross Gross Estimated Fixed maturity securities: U.S. Treasury securities $ 2,912,268 $ 49 $ (126,339) $ 2,785,978 U.S. government-sponsored enterprises 822,815 1,761 (70,863) 753,713 Obligations of states, municipalities and political subdivisions 3,972,514 26,051 (137,823) 3,860,742 Foreign governments 1,402,054 2,675 (107,950) 1,296,779 Commercial mortgage-backed securities 2,013,800 409 (96,890) 1,917,319 Residential mortgage-backed securities 615,940 1,736 (10,146) 607,530 Asset-backed securities 2,165 — (36) 2,129 Corporate bonds 791,401 409 (72,106) 719,704 Total fixed maturity securities 12,532,957 33,090 (622,153) 11,943,894 Short-term investments 2,064,223 1 (8,690) 2,055,534 Investments, available-for-sale $ 14,597,180 $ 33,091 $ (630,843) $ 13,999,428 December 31, 2021 (dollars in thousands) Amortized Gross Gross Estimated Fixed maturity securities: U.S. Treasury securities $ 2,489,032 $ 2,633 $ (21,471) $ 2,470,194 U.S. government-sponsored enterprises 753,029 28,997 (6,439) 775,587 Obligations of states, municipalities and political subdivisions 4,007,211 266,575 (7,862) 4,265,924 Foreign governments 1,394,771 134,071 (9,488) 1,519,354 Commercial mortgage-backed securities 1,928,775 69,810 (8,152) 1,990,433 Residential mortgage-backed securities 699,136 27,084 (170) 726,050 Asset-backed securities 3,035 46 — 3,081 Corporate bonds 786,478 54,475 (4,271) 836,682 Total fixed maturity securities 12,061,467 583,691 (57,853) 12,587,305 Short-term investments 1,805,300 28 (5,340) 1,799,988 Investments, available-for-sale $ 13,866,767 $ 583,719 $ (63,193) $ 14,387,293 b) The following tables summarize gross unrealized investment losses on available-for-sale investments by the length of time that securities have continuously been in an unrealized loss position. June 30, 2022 Less than 12 months 12 months or longer Total (dollars in thousands) Estimated Gross Estimated Gross Estimated Gross Fixed maturity securities: U.S. Treasury securities $ 1,867,197 $ (81,978) $ 911,928 $ (44,361) $ 2,779,125 $ (126,339) U.S. government-sponsored enterprises 509,765 (45,747) 155,794 (25,116) 665,559 (70,863) Obligations of states, municipalities and political subdivisions 1,951,874 (102,522) 210,370 (35,301) 2,162,244 (137,823) Foreign governments 1,016,734 (94,597) 92,286 (13,353) 1,109,020 (107,950) Commercial mortgage-backed securities 1,743,017 (87,792) 64,010 (9,098) 1,807,027 (96,890) Residential mortgage-backed securities 407,445 (9,614) 4,172 (532) 411,617 (10,146) Asset-backed securities 2,129 (36) — — 2,129 (36) Corporate bonds 614,804 (60,001) 66,422 (12,105) 681,226 (72,106) Total fixed maturity securities 8,112,965 (482,287) 1,504,982 (139,866) 9,617,947 (622,153) Short-term investments 2,034,208 (8,690) — — 2,034,208 (8,690) Total $ 10,147,173 $ (490,977) $ 1,504,982 $ (139,866) $ 11,652,155 $ (630,843) At June 30, 2022, the Company held 1,127 available-for-sale securities in an unrealized loss position with a total estimated fair value of $11.7 billion and gross unrealized losses of $630.8 million. Of these 1,127 securities, 110 securities had been in a continuous unrealized loss position for one year or longer and had a total estimated fair value of $1.5 billion and gross unrealized losses of $139.9 million. The Company does not intend to sell or believe it will be required to sell these available-for-sale securities before recovery of their amortized cost. December 31, 2021 Less than 12 months 12 months or longer Total (dollars in thousands) Estimated Gross Estimated Gross Estimated Gross Fixed maturity securities: U.S. Treasury securities $ 2,236,637 $ (18,433) $ 97,173 $ (3,038) $ 2,333,810 $ (21,471) U.S. government-sponsored enterprises 381,495 (5,640) 14,010 (799) 395,505 (6,439) Obligations of states, municipalities and political subdivisions 393,249 (6,941) 23,589 (921) 416,838 (7,862) Foreign governments 322,813 (8,596) 25,564 (892) 348,377 (9,488) Commercial mortgage-backed securities 345,616 (7,765) 9,189 (387) 354,805 (8,152) Residential mortgage-backed securities 12,828 (159) 269 (11) 13,097 (170) Corporate bonds 193,786 (4,271) — — 193,786 (4,271) Total fixed maturity securities 3,886,424 (51,805) 169,794 (6,048) 4,056,218 (57,853) Short-term investments 228,870 (5,340) — — 228,870 (5,340) Total $ 4,115,294 $ (57,145) $ 169,794 $ (6,048) $ 4,285,088 $ (63,193) At December 31, 2021, the Company held 277 available-for-sale securities in an unrealized loss position with a total estimated fair value of $4.3 billion and gross unrealized losses of $63.2 million. Of these 277 securities, 13 securities had been in a continuous unrealized loss position for one year or longer and had a total estimated fair value of $169.8 million and gross unrealized losses of $6.0 million. The Company completes a detailed analysis each quarter to assess whether the decline in the fair value of any investment below its cost basis is the result of a credit loss. All available-for-sale securities with unrealized losses are reviewed. The Company considers many factors in completing its quarterly review of securities with unrealized losses for credit-related impairment to determine whether a credit loss exists, including the extent to which fair value is below cost, the implied yield to maturity, rating downgrades of the security and whether or not the issuer has failed to make scheduled principal or interest payments. The Company also takes into consideration information about the financial condition of the issuer and industry factors that could negatively impact the capital markets. If the decline in fair value of an available-for-sale security below its amortized cost is considered to be the result of a credit loss, the Company compares the estimated present value of the cash flows expected to be collected to the amortized cost of the security. The extent to which the estimated present value of the cash flows expected to be collected is less than the amortized cost of the security represents the credit loss, which is recorded as an allowance and recognized in net income. The allowance is limited to the difference between the fair value and the amortized cost of the security. Any remaining decline in fair value represents the non-credit portion of the impairment, which is recognized in other comprehensive income. The Company did not have an allowance for credit losses as of June 30, 2022 or December 31, 2021. Quarterly, the Company also considers whether it intends to sell an available-for-sale security or if it is more likely than not that it will be required to sell the security before recovery of its amortized cost. In these instances, a decline in fair value is recognized in net income based on the fair value of the security at the time of assessment, resulting in a new cost basis for the security. c) The amortized cost and estimated fair value of fixed maturity securities at June 30, 2022 are shown below by contractual maturity. (dollars in thousands) Amortized Estimated Due in one year or less $ 1,213,444 $ 1,193,593 Due after one year through five years 3,778,157 3,628,633 Due after five years through ten years 2,877,515 2,672,144 Due after ten years 2,031,936 1,922,546 9,901,052 9,416,916 Commercial mortgage-backed securities 2,013,800 1,917,319 Residential mortgage-backed securities 615,940 607,530 Asset-backed securities 2,165 2,129 Total fixed maturity securities $ 12,532,957 $ 11,943,894 d) The following table presents the components of net investment income. Quarter Ended June 30, Six Months Ended June 30, (dollars in thousands) 2022 2021 2022 2021 Interest: Tax-exempt municipal bonds $ 13,160 $ 14,102 $ 26,735 $ 29,338 Taxable municipal bonds 17,618 16,421 35,125 32,916 Other taxable bonds 41,142 40,618 81,204 80,013 Short-term investments, including overnight deposits 5,795 874 7,001 1,546 Dividends on equity securities 23,590 19,798 48,327 45,183 Income (loss) from equity method investments (3,247) 9,018 (29,493) 12,943 Other (308) (417) 5,938 (612) 97,750 100,414 174,837 201,327 Investment expenses (4,092) (4,153) (8,445) (8,496) Net investment income $ 93,658 $ 96,261 $ 166,392 $ 192,831 e) The following table presents the components of net investment gains (losses) and the change in net unrealized gains (losses) included in other comprehensive income (loss). Gross realized investment gains and losses on fixed maturity securities, short-term investments and other investments were not material to the consolidated financial statements and are presented on a net basis in the following table. Quarter Ended June 30, Six Months Ended June 30, (dollars in thousands) 2022 2021 2022 2021 Fixed maturity securities, short-term investments and other investments: Net realized investment gains (losses) $ (2,259) $ 4,402 $ 3,969 $ 7,811 Equity securities: Change in fair value of securities sold during the period (2,113) 1,345 (19,231) 3,971 Change in fair value of securities held at the end of the period (1,550,271) 669,006 (1,897,780) 1,189,842 Total change in fair value (1,552,384) 670,351 (1,917,011) 1,193,813 Net investment gains (losses) $ (1,554,643) $ 674,753 $ (1,913,042) $ 1,201,624 Change in net unrealized gains (losses) on available-for-sale investments included in other comprehensive income (loss): Fixed maturity securities $ (449,089) $ 62,948 $ (1,114,899) $ (258,284) Short-term investments (9,239) 1,095 (3,377) 1,779 Reserve deficiency adjustment for life and annuity benefit reserves (see note 9) — 929 56,560 50,262 Net increase (decrease) $ (458,328) $ 64,972 $ (1,061,716) $ (206,243) f) The Company's equity method investments, which totaled $489.4 million and $459.7 million as of June 30, 2022 and December 31, 2021, respectively, are included in other assets on the consolidated balance sheets. The Company's most significant equity method investment is an investment in Hagerty, Inc. (Hagerty), which is accounted for on a quarter lag. Hagerty is an automotive enthusiast brand offering integrated membership products and programs as well as a specialty insurance provider focused on the global automobile enthusiast market. The Company's ownership interest in Hagerty was 23% as of June 30, 2022 and December 31, 2021. The Company's investment is comprised of Class A common shares, which are listed for trading on the New York Stock Exchange, as well as Class V common shares, associated with the Company's original investment in 2019, that have special voting rights and can be converted on a one-for-one basis into Class A common shares. The Company accounts for its investment under the equity method as it is deemed to have the ability to exercise significant influence over Hagerty's operating and financial policies through a combination of its voting interest, its right to designate a board member and business it conducts with Hagerty. As of June 30, 2022 and December 31, 2021, the carrying value of the Company's investment in Hagerty was $241.6 million and $256.6 million, respectively. As of June 30, 2022 and December 31, 2021, the estimated value of the Company's investment, based on the closing stock price of Hagerty's Class A common shares, was $896.2 million and $1.1 billion, respectively. See note 12 for further details regarding related party transactions with Hagerty.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements FASB ASC 820, Fair Value Measurements and Disclosures, establishes a three-level hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The fair value hierarchy gives the highest priority to quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). If the inputs used to measure the assets or liabilities fall within different levels of the hierarchy, the classification is based on the lowest level input that is significant to the fair value measurement of the asset or liability. Classification of assets and liabilities within the hierarchy considers the markets in which the assets and liabilities are traded and the reliability and transparency of the assumptions used to determine fair value. The hierarchy requires the use of observable market data when available. The levels of the hierarchy are defined as follows: • Level 1 – Inputs to the valuation methodology are quoted prices (unadjusted) for identical assets or liabilities traded in active markets. • Level 2 – Inputs to the valuation methodology include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability and market-corroborated inputs. • Level 3 – Inputs to the valuation methodology are unobservable for the asset or liability and are significant to the fair value measurement. In accordance with ASC 820, the Company determines fair value based on the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. In determining fair value, the Company uses various methods, including the market, income and cost approaches. The Company uses valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. The following section describes the valuation methodologies used by the Company to measure assets and liabilities at fair value, including an indication of the level within the fair value hierarchy in which each asset or liability is generally classified. Available-for-sale investments and equity securities. Available-for-sale investments and equity securities are recorded at fair value on a recurring basis. Available-for-sale investments include fixed maturity securities and short-term investments. Short-term investments include certificates of deposit, commercial paper, discount notes and treasury bills with original maturities of one year or less. Fair value is determined by the Company after considering various sources of information, including information provided by a third-party pricing service. The pricing service provides prices for substantially all of the Company's fixed maturity securities and equity securities. In determining fair value, the Company generally does not adjust the prices obtained from the pricing service. The Company obtains an understanding of the pricing service's valuation methodologies and related inputs, which include, but are not limited to, reported trades, benchmark yields, issuer spreads, bids, offers, duration, credit ratings, estimated cash flows and prepayment speeds. The Company validates prices provided by the pricing service by reviewing prices from other pricing sources and analyzing pricing data in certain instances. The Company has evaluated the various types of securities in its investment portfolio to determine an appropriate fair value hierarchy level based upon trading activity and the observability of market inputs. Level 1 investments include those traded on an active exchange, such as the New York Stock Exchange. Level 2 investments include U.S. Treasury securities, U.S. government-sponsored enterprises, municipal bonds, foreign government bonds, commercial mortgage-backed securities, residential mortgage-backed securities, asset-backed securities and corporate debt securities. Level 3 investments include the Company's investments in insurance-linked securities funds that are not traded on an active exchange and are valued using unobservable inputs. Fair value for available-for-sale investments and equity securities is measured based upon quoted prices in active markets, if available. Due to variations in trading volumes and the lack of quoted market prices, fixed maturity securities are classified as Level 2 investments. The fair value of fixed maturity securities is normally derived through recent reported trades for identical or similar securities, making adjustments through the reporting date based upon available market observable data previously described. If there are no recent reported trades, the fair value of fixed maturity securities may be derived through the use of matrix pricing or model processes, where future cash flow expectations are developed based upon collateral performance and discounted at an estimated market rate. Significant inputs used to determine the fair value of obligations of states, municipalities and political subdivisions, corporate bonds and obligations of foreign governments include reported trades, benchmark yields, issuer spreads, bids, offers, credit information and estimated cash flows. Significant inputs used to determine the fair value of commercial mortgage-backed securities, residential mortgage-backed securities and asset-backed securities include the type of underlying assets, benchmark yields, prepayment speeds, collateral information, tranche type and volatility, estimated cash flows, credit information, default rates, recovery rates, issuer spreads and the year of issue. Due to the significance of unobservable inputs required in measuring the fair value of the Company's investments in certain insurance-linked securities funds, these investments are classified as Level 3 within the fair value hierarchy. The fair value of the securities is derived using their reported net asset value (NAV) as the primary input, as well as other observable and unobservable inputs as deemed necessary by management. Management has obtained an understanding of the inputs, assumptions, process and controls used to determine NAV, which is calculated by an independent third party. Unobservable inputs to the NAV calculations include assumptions around premium earnings patterns and loss reserve estimates for the underlying securitized reinsurance contracts. The Company's valuation policies and procedures for Level 3 investments are determined by management. Fair value measurements are analyzed quarterly to ensure the change in fair value from prior periods is reasonable relative to management's understanding of the underlying investments, recent market trends and external market data. Senior long-term debt and other debt. Senior long-term debt and other debt is carried at amortized cost with the estimated fair value disclosed on the consolidated balance sheets. Senior long-term debt and other debt is classified as Level 2 within the fair value hierarchy due to variations in trading volumes and the lack of quoted market prices. Fair value is generally derived through recent reported trades for identical securities, making adjustments through the reporting date, if necessary, based upon available market observable data including U.S. Treasury securities and implied credit spreads. Significant inputs used to determine the fair value of senior long-term debt and other debt include reported trades, benchmark yields, issuer spreads, bids and offers. The following tables present the balances of assets measured at fair value on a recurring basis by level within the fair value hierarchy. June 30, 2022 (dollars in thousands) Level 1 Level 2 Level 3 Total Assets: Investments: Fixed maturity securities, available-for-sale: U.S. Treasury securities $ — $ 2,785,978 $ — $ 2,785,978 U.S. government-sponsored enterprises — 753,713 — 753,713 Obligations of states, municipalities and political subdivisions — 3,860,742 — 3,860,742 Foreign governments — 1,296,779 — 1,296,779 Commercial mortgage-backed securities — 1,917,319 — 1,917,319 Residential mortgage-backed securities — 607,530 — 607,530 Asset-backed securities — 2,129 — 2,129 Corporate bonds — 719,704 — 719,704 Total fixed maturity securities, available-for-sale — 11,943,894 — 11,943,894 Equity securities: Insurance, banks and other financial institutions 2,741,363 — 4,380 2,745,743 Industrial, consumer and all other 4,424,258 — — 4,424,258 Total equity securities 7,165,621 — 4,380 7,170,001 Short-term investments, available-for-sale 1,892,694 162,840 — 2,055,534 Total investments $ 9,058,315 $ 12,106,734 $ 4,380 $ 21,169,429 December 31, 2021 (dollars in thousands) Level 1 Level 2 Level 3 Total Assets: Investments: Fixed maturity securities, available-for-sale: U.S. Treasury securities $ — $ 2,470,194 $ — $ 2,470,194 U.S. government-sponsored enterprises — 775,587 — 775,587 Obligations of states, municipalities and political subdivisions — 4,265,924 — 4,265,924 Foreign governments — 1,519,354 — 1,519,354 Commercial mortgage-backed securities — 1,990,433 — 1,990,433 Residential mortgage-backed securities — 726,050 — 726,050 Asset-backed securities — 3,081 — 3,081 Corporate bonds — 836,682 — 836,682 Total fixed maturity securities, available-for-sale — 12,587,305 — 12,587,305 Equity securities: Insurance, banks and other financial institutions 3,307,755 — 56,472 3,364,227 Industrial, consumer and all other 5,659,700 — — 5,659,700 Total equity securities 8,967,455 — 56,472 9,023,927 Short-term investments, available-for-sale 1,619,496 180,492 — 1,799,988 Total investments $ 10,586,951 $ 12,767,797 $ 56,472 $ 23,411,220 The following table summarizes changes in Level 3 investments measured at fair value on a recurring basis. Quarter Ended June 30, Six Months Ended June 30, (dollars in thousands) 2022 2021 2022 2021 Equity securities, beginning of period $ 8,468 $ 56,138 $ 56,472 $ 58,493 Purchases — — — — Sales (4,027) (15,015) (52,807) (15,015) Net investment gains (losses) (61) (57) 715 (2,412) Equity securities, end of period $ 4,380 $ 41,066 $ 4,380 $ 41,066 As of June 30, 2022, the Company's remaining Level 3 investment relates to its investment in Lodgepine Fund Limited, an insurance-linked securities fund managed through the Company's Lodgepine operations, which are currently in run-off. Previously, Level 3 investments also included the Company's investment in an insurance-linked securities fund managed by Markel CATCo Investment Management Ltd. (MCIM). During the first quarter of 2022, the Company's remaining investment was redeemed ($41.3 million) in conjunction with a buy-out transaction that provided for an accelerated return of all remaining capital to investors. See note 11 for further details about the Company's Markel CATCo operations and the buy-out transaction. Except as disclosed in note 3, the Company did not have any assets or liabilities measured at fair value on a non-recurring basis during the six months ended June 30, 2022 and 2021.

Products, Services and Other Re

Products, Services and Other Revenues	6 Months Ended
	Jun. 30, 2022
Revenue from Contract with Customer [Abstract]
Products, Services and Other Revenues	Products, Services and Other Revenues The amount of revenues from contracts with customers was $1.4 billion and $1.1 billion for the quarters ended June 30, 2022 and 2021, respectively, and $2.3 billion and $1.8 billion for the six months ended June 30, 2022 and 2021, respectively. The following tables present revenues from contracts with customers by segment and type, all of which are included in products revenues and services and other revenues in the consolidated statements of income (loss) and comprehensive income (loss), along with a reconciliation to total products revenues and services and other revenues. Quarter Ended June 30, 2022 2021 (dollars in thousands) Markel Ventures Other Total Markel Ventures Other Total Products $ 764,543 $ — $ 764,543 $ 581,321 $ — $ 581,321 Services 569,385 8,450 577,835 468,424 37,902 506,326 Investment management — 20,328 20,328 — 20,785 20,785 Total revenues from contracts with customers 1,333,928 28,778 1,362,706 1,049,745 58,687 1,108,432 Program services and other fronting — 29,731 29,731 — 27,399 27,399 Other 27,370 281 27,651 25,759 131 25,890 Total $ 1,361,298 $ 58,790 $ 1,420,088 $ 1,075,504 $ 86,217 $ 1,161,721 Six Months Ended June 30, 2022 2021 (dollars in thousands) Markel Ventures Other Total Markel Ventures Other Total Products $ 1,233,999 $ — $ 1,233,999 $ 899,963 $ — $ 899,963 Services 1,018,834 30,018 1,048,852 825,112 65,881 890,993 Investment management — 39,556 39,556 — 37,122 37,122 Total revenues from contracts with customers 2,252,833 69,574 2,322,407 1,725,075 103,003 1,828,078 Program services and other fronting — 63,063 63,063 — 55,016 55,016 Disposition gain — 107,293 107,293 — — — Other 58,850 606 59,456 57,028 657 57,685 Total $ 2,311,683 $ 240,536 $ 2,552,219 $ 1,782,103 $ 158,676 $ 1,940,779 Receivables from contracts with customers were $723.0 million and $626.1 million as of June 30, 2022 and December 31, 2021, respectively.

Unpaid Losses And Loss Adjustme

Unpaid Losses And Loss Adjustment Expenses	6 Months Ended
	Jun. 30, 2022
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract]
Unpaid Losses And Loss Adjustment Expenses	Unpaid Losses and Loss Adjustment Expenses The following table presents a reconciliation of consolidated beginning and ending reserves for losses and loss adjustment expenses. Six Months Ended June 30, (dollars in thousands) 2022 2021 Net reserves for losses and loss adjustment expenses, beginning of year $ 11,302,577 $ 10,485,717 Effect of foreign currency rate changes on beginning of year balance (149,383) 5,198 Adjusted net reserves for losses and loss adjustment expenses, beginning of year 11,153,194 10,490,915 Incurred losses and loss adjustment expenses: Current accident year 2,153,910 1,920,907 Prior accident years (122,728) (226,059) Total incurred losses and loss adjustment expenses 2,031,182 1,694,848 Payments: Current accident year 167,262 198,402 Prior accident years 1,291,318 1,190,303 Total payments 1,458,580 1,388,705 Effect of foreign currency rate changes on current year activity 221 (476) Net reserves for losses and loss adjustment expenses of Markel CATCo Re (see note 11) 465,196 — Net reserves for losses and loss adjustment expenses of insurance companies sold — (2,762) Net reserves for losses and loss adjustment expenses, end of period 12,191,213 10,793,820 Reinsurance recoverables on unpaid losses 6,871,547 6,205,996 Gross reserves for losses and loss adjustment expenses, end of period $ 19,062,760 $ 16,999,816 For the six months ended June 30, 2022, current accident year losses and loss adjustment expenses included $35.0 million of net losses and loss adjustment expenses attributed to the Russia-Ukraine conflict. These losses and loss adjustment expenses were net of ceded losses of $70.0 million. All of the gross and net losses and loss adjustment expenses attributed to the Russia-Ukraine conflict were recognized in the first quarter of 2022. Both the gross and net loss estimates for incurred losses attributed to the Russia-Ukraine conflict continue to represent the Company's best estimates as of June 30, 2022 based upon information currently available. The Company's estimates for these losses are based on reported claims, detailed underwriting, actuarial and claims reviews of policies and in-force assumed reinsurance contracts for potential exposures, as well as analysis of ceded reinsurance contracts and analysis provided by the Company's brokers and claims counsel. These estimates include various assumptions about what areas within the affected regions have incurred losses, the nature and extent of such losses, which remain difficult to verify, as well as assumptions about coverage, liability and reinsurance. Due to the inherent uncertainty associated with the assumptions surrounding the Russia-Ukraine conflict, these estimates are subject to a wide range of variability. Additionally, as the Russia-Ukraine conflict is ongoing, the Company believes it is possible that additional losses could be incurred in subsequent periods. Given the significant levels of ceded reinsurance on certain of the Company's impacted policies, a significant portion of any additional incurred losses may be ceded. Additionally, increases in ceded losses may require payment of additional reinstatement premiums. Further, if coverage under the Company's existing ceded reinsurance contracts is exhausted, the Company may need to purchase additional reinsurance to ensure that net retained risks on the impacted product lines are within the Company's corporate risk tolerances. While the Company believes the gross and net reserves for losses and loss adjustment expenses for the Russia-Ukraine conflict as of June 30, 2022 are adequate based on information currently available, the Company continues to closely monitor reported claims, ceded reinsurance contract attachment, government actions and areas impacted by the conflict and may adjust the estimates of gross and net losses as new information becomes available. Any such adjustments or additional incurred losses may be material to the Company's results of operations, financial condition and cash flows. For the six months ended June 30, 2021, current accident year losses and loss adjustment expenses included $67.9 million of net losses and loss adjustment expenses attributed to Winter Storm Uri. For the six months ended June 30, 2022, prior accident years losses and loss adjustment expenses included $122.7 million of favorable development on prior years loss reserves, which included $123.3 million of favorable development on the Company's property, marine and energy, workers' compensation and programs product lines within the Insurance segment. For the six months ended June 30, 2021, prior accident years losses and loss adjustment expenses included $226.1 million of favorable development on prior years loss reserves, which included $213.3 million of favorable development on the Company's general liability, workers' compensation, marine and energy, property and professional liability product lines within the Insurance segment. Favorable development on prior years loss reserves for the six months ended June 30, 2021 was partially offset by $32.8 million of adverse development on the Company's property product lines within the Reinsurance segment, due in part to losses related to COVID-19. The Company's loss estimates for COVID-19 continue to represent the Company's best estimate as of June 30, 2022 based on information currently available, however, the assumptions on which these estimates are based are subject to a wide range of variability. The Company is closely monitoring reported claims, ceded reinsurance contract attachment, government actions and judicial decisions and may adjust the estimates of gross and net losses as new information becomes available. Such adjustments may be material to the Company's results of operations, financial condition and cash flows. For additional details on the Company's COVID-19 loss estimates, readers are urged to review the Company's 2021 Annual Report on Form 10-K.

Reinsurance

Reinsurance	6 Months Ended
	Jun. 30, 2022
Reinsurance Disclosures [Abstract]
Reinsurance	Reinsurance The following tables summarize the effect of reinsurance and retrocessional reinsurance on premiums written and earned. Quarter Ended June 30, 2022 2021 (dollars in thousands) Direct Assumed Ceded Net Premiums Direct Assumed Ceded Net Premiums Underwriting: Written $ 2,108,859 $ 420,026 $ (427,959) $ 2,100,926 $ 1,756,680 $ 344,279 $ (349,037) $ 1,751,922 Earned 1,772,695 382,876 (321,438) 1,834,133 1,511,416 351,931 (294,679) 1,568,668 Program services and other fronting: Written 664,590 86,574 (752,295) (1,131) 737,110 45,944 (783,525) (471) Earned 607,099 65,116 (673,244) (1,029) 582,809 23,763 (607,203) (631) Consolidated: Written 2,773,449 506,600 (1,180,254) 2,099,795 2,493,790 390,223 (1,132,562) 1,751,451 Earned $ 2,379,794 $ 447,992 $ (994,682) $ 1,833,104 $ 2,094,225 $ 375,694 $ (901,882) $ 1,568,037 Six Months Ended June 30, 2022 2021 (dollars in thousands) Direct Assumed Ceded Net Premiums Direct Assumed Ceded Net Premiums Underwriting: Written $ 3,932,114 $ 1,116,386 $ (781,341) $ 4,267,159 $ 3,305,777 $ 966,027 $ (638,350) $ 3,633,454 Earned 3,470,665 785,943 (661,367) 3,595,241 2,942,749 717,829 (593,779) 3,066,799 Program services and other fronting: Written 1,361,564 268,272 (1,632,466) (2,630) 1,345,147 71,914 (1,417,994) (933) Earned 1,306,704 113,976 (1,423,047) (2,367) 1,165,969 38,668 (1,205,704) (1,067) Consolidated: Written 5,293,678 1,384,658 (2,413,807) 4,264,529 4,650,924 1,037,941 (2,056,344) 3,632,521 Earned $ 4,777,369 $ 899,919 $ (2,084,414) $ 3,592,874 $ 4,108,718 $ 756,497 $ (1,799,483) $ 3,065,732 Substantially all of the premiums written and earned in the Company's program services and other fronting operations for the quarters and six months ended June 30, 2022 and 2021 were ceded. The percentage of consolidated ceded earned premiums to gross earned premiums was 35% and 37% for the quarter and six months ended June 30, 2022, respectively, and 37% for both the quarter and six months ended June 30, 2021. The percentage of consolidated assumed earned premiums to net earned premiums was 24% and 25% for the quarter and six months ended June 30, 2022, respectively, and 24% and 25% for the quarter and six months ended June 30, 2021, respectively. Substantially all of the incurred losses and loss adjustment expenses in the Company's program services and other fronting operations were ceded. These losses totaled $574.8 million and $990.5 million for the quarter and six months ended June 30, 2022, respectively, and $636.8 million and $1.1 billion for the quarter and six months ended June 30, 2021, respectively. The following table summarizes the effect of reinsurance and retrocessional reinsurance on losses and loss adjustment expenses in the Company's underwriting operations. Quarter Ended June 30, Six Months Ended June 30, (dollars in thousands) 2022 2021 2022 2021 Gross losses and loss adjustment expenses $ 1,186,691 $ 993,138 $ 2,337,040 $ 2,067,061 Ceded losses and loss adjustment expenses (127,895) (177,674) (305,889) (369,645) Net losses and loss adjustment expenses $ 1,058,796 $ 815,464 $ 2,031,151 $ 1,697,416

Life and Annuity Benefits Life

Life and Annuity Benefits Life and Annuity Benefits	6 Months Ended
	Jun. 30, 2022
Liability for Future Policy Benefit, before Reinsurance [Abstract]
Liability for Future Policy Benefits and Unpaid Claims Disclosure [Text Block]	Life and Annuity BenefitsLife and annuity benefits are compiled on a reinsurance contract-by-contract basis and are discounted using standard actuarial techniques and cash flow models. Since the development of the life and annuity reinsurance reserves is based upon cash flow projection models, the Company must make estimates and assumptions based on cedent experience, industry mortality tables, and expense and investment experience, including a provision for adverse deviation. The assumptions used to determine policy benefit reserves are generally locked-in for the life of the contract unless an unlocking event occurs. Loss recognition testing is performed to determine if existing policy benefit reserves, together with the present value of future gross premiums and expected investment income earned thereon, are adequate to cover the present value of future benefits, settlement and maintenance costs. If the existing policy benefit reserves are not sufficient, the locked-in assumptions are revised to current best estimate assumptions and a charge to earnings for life and annuity benefits is recognized at that time.Life and annuity benefits are also adjusted to the extent unrealized gains on the investments supporting the policy benefit reserves would result in a reserve deficiency if those gains were realized. As of December 31, 2021, the cumulative increase to life and annuity benefits attributable to unrealized gains on the underlying investment portfolio totaled $56.6 million, all of which reversed during the first quarter of 2022 as a result of an increase in the market yield on the investment securities supporting the policy benefit reserves. As the market yield continued to increase, there was no adjustment to life and annuity benefits during the quarter ended June 30, 2022. During the quarter and six months ended June 30, 2021, the Company decreased life and annuity benefits by $0.9 million and $50.3 million, respectively and increased the change in net unrealized holding gains included in other comprehensive income by a corresponding amount.

Debt

Debt	6 Months Ended
	Jun. 30, 2022
Debt Disclosure [Abstract]
Debt Disclosure	Senior Long-Term Debt and Other Debt In June 2022, the Company made a cash payment to a third-party trust account to pre-fund the retirement of its 4.90% unsecured senior notes due July 1, 2022 ($350.0 million aggregate principal outstanding at June 30, 2022). On July 1, 2022, the notes were retired. The Company maintains a corporate revolving credit facility which provides up to $300 million of capacity for future acquisitions, investments and stock repurchases, and for other working capital and general corporate purposes. At the Company's discretion, up to $200 million of the total capacity may be used for letters of credit. The Company may increase the capacity of the facility by up to $200 million subject to obtaining commitments for the increase and certain other terms and conditions. At June 30, 2022 and December 31, 2021, the Company had no borrowings outstanding under this revolving credit facility. This facility expires in April 2024. Various of the Company's Markel Ventures subsidiaries maintain revolving credit facilities or lines of credit, which provide up to $600 million of aggregate capacity for working capital and other general operational purposes. A portion of the capacity on certain of these credit facilities may be used as security for letters of credit and other obligations. At June 30, 2022 and December 31, 2021, the Company had $296.1 million and $94.3 million, respectively, of borrowings outstanding under these credit facilities. To the extent that the Company or any of its subsidiaries are not in compliance with the covenants under their respective credit facilities, access to such credit facilities could be restricted. At June 30, 2022, the Company and all of the Company's subsidiaries were in compliance with all covenants contained in their respective credit facilities.

Variable Interest Entities

Variable Interest Entities	6 Months Ended
	Jun. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	Variable Interest Entities MCIM, a wholly-owned consolidated subsidiary of the Company, is an insurance-linked securities investment fund manager and reinsurance manager headquartered in Bermuda. Results attributable to MCIM are not included in a reportable segment. MCIM serves as the insurance manager for Markel CATCo Re Ltd. (Markel CATCo Re), a Bermuda Class 3 reinsurance company, and as the investment manager for Markel CATCo Reinsurance Fund Ltd., a Bermuda exempted mutual fund company comprised of multiple segregated accounts (Markel CATCo Funds). Voting shares in Markel CATCo Reinsurance Fund Ltd. and Markel CATCo Re are held by MCIM, which has the power to direct the activities that most significantly impact the economic performance of these entities. The Markel CATCo Funds issued multiple classes of nonvoting, redeemable preference shares to investors, and the Markel CATCo Funds are primarily invested in nonvoting preference shares of Markel CATCo Re. The underwriting results of Markel CATCo Re are attributed to investors through its nonvoting preference shares. Both Markel CATCo Re and the Markel CATCo Funds were placed into run-off in July 2019. In March 2022, the Company completed a buy-out transaction with Markel CATCo Re and the Markel CATCo Funds that provided for an accelerated return of all remaining capital to investors in the Markel CATCo Funds. Under the terms of the transaction, the Company provided cash funding of $45.1 million to purchase substantially all of the Markel CATCo Funds' interests in Markel CATCo Re. See note 14 for further details regarding the terms of the buy-out transaction. As part of the transaction, substantially all of the preference shares held by investors in the Markel CATCo Funds were redeemed, including preference shares previously held by the Company. See note 5 for details regarding the Company's investment in the Markel CATCo Funds. During June 2022, the Company received a return of $24.9 million of the capital it provided in March 2022 and the related preference shares were redeemed. As of June 30, 2022, the Company's investment in preference shares of Markel CATCo Re totaled $20.1 million, which comprised 74% of the equity of Markel CATCo Re. Through that investment, the Company has exposure to adverse loss development on reinsurance contracts previously written by Markel CATCo Re for loss events that occurred from 2014 to 2020. If loss reserves held by Markel CATCo Re are sufficient to settle claims on the remaining open contracts, the Company will receive a full return of the remaining $20.1 million capital provided in March 2022. Favorable development on loss reserves held by Markel CATCo Re, less operating expenses, will be distributed to the Markel CATCo Funds, and ultimately to investors in the Markel CATCo Funds. Markel CATCo Re is considered a VIE, as the equity at risk does not have the right to receive residual returns that exceed the capital provided by the Company in the buy-out transaction. As a result of the preference shares acquired by the Company in the buy-out transaction, and the voting shares held by its consolidated subsidiary, MCIM, the Company consolidates Markel CATCo Re as its primary beneficiary. Results attributed to the run-off of Markel CATCo Re are reported with the Company's other ILS operations, within services and other revenues and expenses, and are not included in a reportable segment. The Company's consolidated balance sheet includes the following amounts attributable to Markel CATCo Re. (dollars in thousands) June 30, 2022 Assets Cash and cash equivalents $ 75,144 Restricted cash and cash equivalents 357,974 Other assets and receivables due from cedents 81,751 Total Assets $ 514,869 Liabilities and Equity Unpaid losses and loss adjustment expenses $ 465,196 Other liabilities 22,596 Total Liabilities 487,792 Shareholders' Equity 21,139 Noncontrolling interests 5,938 Total Equity 27,077 Total Liabilities and Equity $ 514,869 In connection with the buy-out transaction, the Company also entered into a tail risk cover with Markel CATCo Re. Through this contract, the Company has $142.7 million of uncollateralized exposure to adverse development on loss reserves held by Markel CATCo Re for loss exposures in excess of limits that the Company believes are unlikely to be exceeded.

Related Party Transactions Rela

Related Party Transactions Related Party Transactions	6 Months Ended
	Jun. 30, 2022
Related Party Transactions [Abstract]
Related Party Transactions Disclosure [Text Block]	Related Party Transactions The Company engages in certain related party transactions in the normal course of business at arm's length. Insurance-Linked Securities Within the Company's insurance-linked securities operations, the Company provides investment and insurance management services through Nephila Holdings Ltd. (together with its subsidiaries, Nephila). Nephila serves as the investment manager to several Bermuda, Ireland and U.S. based private funds (the Nephila Funds). To provide access for the Nephila Funds to the insurance, reinsurance and weather markets, Nephila also acts as an insurance manager to certain Bermuda Class 3 and 3A reinsurance companies and Lloyd's of London Syndicate 2357 (Syndicate 2357) (collectively, the Nephila Reinsurers). Nephila receives management fees for investment and insurance management services provided through its insurance-linked securities operations based on the net asset value of the accounts managed, and, for certain funds, incentive fees based on the annual performance of the funds managed. Prior to the disposition of Velocity in February 2022, Nephila also provided managing general agent services to the Nephila Reinsurers in exchange for commissions. For the quarter and six months ended June 30, 2022, total revenues attributed to unconsolidated entities managed by Nephila were $17.5 million and $39.9 million, respectively. For the quarter and six months ended June 30, 2021, total revenues attributed to unconsolidated entities managed by Nephila were $42.0 million and $70.7 million, respectively. Through the Company's program services operations and other fronting arrangements, the Company has programs with Nephila through which the Company writes insurance policies that are ceded to Syndicate 2357 and certain other Nephila Reinsurers. Through these programs, Nephila utilizes certain of the Company's licensed insurance companies to write U.S. catastrophe-exposed property risk that is then ceded to Nephila Reinsurers. Gross premiums written through these programs with Nephila were $317.7 million and $633.3 million for the quarter and six months ended June 30, 2022, respectively, and $186.7 million and $304.0 million for the quarter and six months ended June 30, 2021, respectively, all of which were ceded to Nephila Reinsurers. As of June 30, 2022 and December 31, 2021, reinsurance recoverables on the consolidated balance sheets included $598.0 million and $751.0 million, respectively, due from Nephila Reinsurers. Under these programs, the Company bears underwriting risk for annual aggregate agreement year losses in excess of a limit the Company believes is unlikely to be exceeded. To the extent losses under these programs exceed the prescribed limits, the Company is obligated to pay such losses to the cedents without recourse to the Nephila Reinsurers. While the Company believes losses under these programs are unlikely, those losses, if incurred, could be material to the Company's consolidated results of operations and financial condition. The Company has also entered into other assumed and ceded reinsurance transactions with the Nephila Reinsurers in the normal course of business, which are not material to the Company's consolidated financial statements. Hagerty The Company holds a minority ownership interest in Hagerty, which operates primarily as a managing general agent and also includes Hagerty Re, a Bermuda Class 3 reinsurance company. Through the Company's underwriting operations, the Company underwrites insurance for Hagerty, and a portion of this insurance is ceded to Hagerty Re. For the quarter and six months ended June 30, 2022, the Company's gross written premiums attributable to Hagerty were $204.4 million and $343.4 million, respectively, of which $135.2 million and $227.3 million, respectively, were ceded to Hagerty Re. For the quarter and six months ended June 30, 2021, the Company's gross written premiums attributable to Hagerty were $177.6 million and $297.5 million, respectively, of which $100.9 million and $168.8 million, respectively, were ceded to Hagerty Re.

Shareholders' Equity

Shareholders' Equity	6 Months Ended
	Jun. 30, 2022
Stockholders' Equity Note [Abstract]
Shareholders' Equity Note Disclosure	Shareholders' Equity a) The Company has 50,000,000 shares of no par value common stock authorized. The following table presents a rollforward of changes in common shares issued and outstanding. Quarter Ended June 30, Six Months Ended June 30, (in thousands) 2022 2021 2022 2021 Issued and outstanding common shares, beginning of period 13,570 13,765 13,632 13,783 Issuance of common shares 1 2 2 3 Repurchase of common shares (33) (33) (96) (52) Issued and outstanding common shares, end of period 13,538 13,734 13,538 13,734 b) The Company also has 10,000,000 shares of no par value preferred stock authorized, of which 600,000 shares were issued and outstanding at June 30, 2022 and December 31, 2021. The Company declared and paid dividends on preferred shares of $18.0 million, or $30 per share, in both the quarter ended June 30, 2022 and 2021. c) Net income (loss) per common share was determined by dividing adjusted net income (loss) to common shareholders by the applicable weighted average common shares outstanding. Basic common shares outstanding include restricted stock units that are no longer subject to any contingencies for issuance, but for which corresponding shares have not been issued. Diluted net income (loss) per common share is computed by dividing adjusted net income (loss) to common shareholders by the weighted average number of common shares and dilutive potential common shares outstanding during the period. The following table presents net income (loss) per common share and diluted net income (loss) per common share. Quarter Ended June 30, Six Months Ended June 30, (in thousands, except per share amounts) 2022 2021 2022 2021 Net income (loss) to common shareholders $ (934,359) $ 774,110 $ (987,202) $ 1,347,804 Adjustment of redeemable noncontrolling interests (7,498) 13,717 (44,438) 21,623 Adjusted net income (loss) to common shareholders $ (941,857) $ 787,827 $ (1,031,640) $ 1,369,427 Basic common shares outstanding 13,612 13,793 13,632 13,806 Dilutive potential common shares from restricted stock units and restricted stock (1) — 24 — 22 Diluted common shares outstanding 13,612 13,817 13,632 13,828 Basic net income (loss) per common share $ (69.19) $ 57.12 $ (75.68) $ 99.19 Diluted net income (loss) per common share (1) $ (69.19) $ 57.02 $ (75.68) $ 99.03 (1) The impact of 31 thousand and 29 thousand shares from restricted stock units and restricted stock was excluded from the computation of diluted net loss per common share for the quarter and six months ended June 30, 2022, respectively, because the effect would have been anti-dilutive.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2022
Loss Contingency [Abstract]
Commitments and Contingencies	Commitments and Contingencies a) In March 2022, the Company completed a buy-out transaction with Markel CATCo Re and the Markel CATCo Funds, which are currently in run-off, that provided for an accelerated return of all remaining capital to investors in the Markel CATCo Funds. Under the terms of the transaction, the Company provided cash funding of $45.1 million to purchase substantially all of the Markel CATCo Funds' investments in Markel CATCo Re and also provided tail risk cover of $142.7 million to Markel CATCo Re to allow for the release of collateral to investors. In order to complete the transaction, the Company also made $101.9 million in additional payments, net of insurance proceeds, to or for the benefit of investors, which were recognized as an expense to the Company and included in services and other expenses for the six months ended June 30, 2022. In conjunction with the buy-out transaction, all investors holding securities in the Markel CATCo Funds, the Markel CATCo Group Companies (MCIM, the Markel CATCo Funds and Markel CATCo Re), Markel Corporation and each of their related parties, among others, granted mutual releases of all claims related to the transaction, the Markel CATCo Group Companies' businesses and the investors' investments in the Funds, including any pending litigation. See note 11 for further details about the Company's Markel CATCo operations and the buy-out transaction. b) Contingencies arise in the normal course of the Company's operations and are not expected to have a material impact on the Company's financial condition or results of operations.

Accounting Changes and Error Co

Accounting Changes and Error Corrections	Jan. 01, 2021
Accounting Changes and Error Corrections [Abstract]
Immaterial Correction to Prior Period Financial Statements for Accounting Policy Change	Immaterial Correction to Prior Period Financial Statements for Accounting Policy Change The Company defers and amortizes costs directly related to the successful acquisition of new or renewal insurance contracts over the related policy period, generally one year. Previously, the Company did not defer salaries and benefits associated with the successful acquisition of insurance contracts, as such amounts were quantified and assessed each period and were deemed not to be material to the consolidated financial statements. Effective January 1, 2022, the Company changed its accounting policy to defer salaries and benefits associated with the successful acquisition of insurance contracts in accordance with the requirements of FASB ASC 944, Financial Services—Insurance . To reflect the change in accounting policy, the Company made a cumulative adjustment to increase deferred policy acquisition costs by $28.2 million, increase deferred tax liabilities by $5.9 million and increase retained earnings by $22.3 million as of January 1, 2020, which is the beginning of the earliest year that will be presented in the consolidated financial statements included in the Company's 2022 Annual Report on Form 10-K. These increases in deferred policy acquisition costs, deferred tax liabilities and retained earnings are also reflected as increases to the previously reported amounts in the Company's consolidated balance sheets as of December 31, 2021 and as an adjustment to retained earnings as of January 1, 2021 in the accompanying consolidated statement of changes in equity for the six months ended June 30, 2021. The Company considered both the quantitative and qualitative factors within the provisions of U.S. Securities and Exchange Commission Staff Accounting Bulletin (SAB) No. 99, Materiality , and SAB No. 108, Considering the Effect of Prior Year Misstatements when Quantifying Misstatements in Current Year Financial Statements

Summary Of Significant Accoun_2

Summary Of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation. The consolidated balance sheet as of June 30, 2022 and the related consolidated statements of income (loss) and comprehensive income (loss) and changes in equity for the quarters and six months ended June 30, 2022 and 2021, and the condensed consolidated statements of cash flows for the six months ended June 30, 2022 and 2021 are unaudited. In the opinion of management, all adjustments necessary for fair presentation of such consolidated financial statements have been included. Except for the adjustment described in note 15, such adjustments consist only of normal, recurring items. Interim results are not necessarily indicative of results of operations for the entire year. The consolidated balance sheet as of December 31, 2021 was derived from Markel Corporation's audited annual consolidated financial statements. The accompanying consolidated financial statements have been prepared in accordance with United States (U.S.) generally accepted accounting principles (GAAP) and include the accounts of Markel Corporation and its consolidated subsidiaries, as well as any variable interest entities (VIEs) that meet the requirements for consolidation (the Company). All significant intercompany balances and transactions have been eliminated in consolidation. The Company consolidates the results of its Markel Ventures subsidiaries on a one-month lag, with the exception of significant transactions or events that occur during the intervening period. Certain prior period amounts have been reclassified to conform to the current period presentation. 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. Actual results may differ materially from the estimates and assumptions used in preparing the consolidated financial statements. The consolidated financial statements and notes are presented as permitted by Form 10-Q and do not contain certain information included in the Company's annual consolidated financial statements and notes. For a more complete description of the Company's business and accounting policies, readers are urged to review the Company's 2021 Annual Report on Form 10-K, as well as note 15 for details regarding a change to the Company's policy for accounting for deferred policy acquisition costs.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Accounting Standards Not Yet Adopted In August 2018, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2018-12, Financial Services—Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts. The FASB subsequently issued several ASUs as amendments to ASU No. 2018-12. The standard requires insurance companies with long duration contracts to: (1) review and, if there is a change, update the assumptions used to measure expected cash flows at least annually; (2) update the discount rate assumption at each reporting date; and (3) enhance disclosures, which includes (i) providing information about significant inputs, judgments and assumptions used to measure the liability and (ii) expanding the quantitative disclosures. ASU No. 2018-12 becomes effective for the Company during the first quarter of 2023 and will be applied using a modified retrospective approach that requires restatement of prior periods presented, including a cumulative adjustment to beginning accumulated other comprehensive income for the earliest period presented. The standard will, among other things, impact the discount rate used in estimating reserves for the Company's life and annuity reinsurance portfolio, which is in runoff. Currently, the discount rate assumption is locked-in for the life of the contracts, unless there is a loss recognition event. The Company is currently evaluating ASU No. 2018-12 to determine the impact that adopting this standard will have on its consolidated financial statements. In October 2021, the FASB issued ASU No. 2021-08, Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customer s, which becomes effective for the Company during the first quarter of 2023. ASU No. 2021-08 requires contract assets and liabilities accounted for under FASB Accounting Standards Codification (ASC) 606, Revenue from Contracts with Customers , to be recorded at the acquisition date as if the acquirer entered into those contracts itself on the contract inception dates, rather than at fair value. At adoption, ASU No. 2021-08 will not impact the Company's financial position, results of operations or cash flows, but prospectively, this ASU will impact amounts recorded by the Company for assets acquired and liabilities assumed in conjunction with certain acquisitions.

Segment Reporting Disclosures (

Segment Reporting Disclosures (Tables)	6 Months Ended
	Jun. 30, 2022
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Company's Segment Disclosures	The following tables summarize the Company's segment disclosures. Quarter Ended June 30, 2022 (dollars in thousands) Insurance Reinsurance Investing Markel Ventures (1) Other (2) Consolidated Gross premium volume $ 2,237,158 $ 289,056 $ — $ — $ 753,835 $ 3,280,049 Net written premiums 1,828,162 273,838 — — (2,205) 2,099,795 Earned premiums 1,570,001 264,154 — — (1,051) 1,833,104 Losses and loss adjustment expenses: Current accident year (919,283) (165,932) — — — (1,085,215) Prior accident years 43,693 (13,577) — — (3,711) 26,405 Underwriting, acquisition and insurance expenses: Amortization of policy acquisition costs (323,826) (69,125) — — (32) (392,983) Other underwriting expenses (204,171) (11,681) — — (634) (216,486) Underwriting profit (loss) 166,414 3,839 — — (5,428) 164,825 Net investment income — — 93,558 100 — 93,658 Net investment losses — — (1,554,643) — — (1,554,643) Products revenues — — — 776,959 — 776,959 Services and other revenues — — — 584,339 58,790 643,129 Products expenses — — — (697,718) — (697,718) Services and other expenses — — — (536,057) (23,801) (559,858) Amortization of intangible assets (3) — — — (20,577) (24,946) (45,523) Segment profit (loss) $ 166,414 $ 3,839 $ (1,461,085) $ 107,046 $ 4,615 $ (1,179,171) Interest expense (50,050) Net foreign exchange gains 106,732 Loss before income taxes $ (1,122,489) U.S. GAAP combined ratio (4) 89 % 99 % NM (5) 91 % (1) Products expenses and services and other expenses for the Markel Ventures segment include depreciation expense of $26.5 million for the quarter ended June 30, 2022. (2) Other represents the total profit (loss) attributable to the Company's operations that are not included in a reportable segment as well as any amortization of intangible assets that is not allocated to a reportable segment. Amortization of intangible assets attributable to the Company's underwriting segments was $9.6 million for the quarter ended June 30, 2022, however, the Company does not allocate amortization of intangible assets between the Insurance and Reinsurance segments. (3) Segment profit for the Markel Ventures segment includes amortization of intangible assets attributable to Markel Ventures. Amortization of intangible assets is not allocated to the Company's Insurance and Reinsurance segments. (4) The U.S. GAAP combined ratio is a measure of underwriting performance and represents the relationship of incurred losses, loss adjustment expenses and underwriting, acquisition and insurance expenses to earned premiums. (5) NM - Ratio is not meaningful Quarter Ended June 30, 2021 (dollars in thousands) Insurance Reinsurance Investing Markel Ventures (1) Other (2) Consolidated Gross premium volume $ 1,821,374 $ 279,444 $ — $ — $ 783,195 $ 2,884,013 Net written premiums 1,494,443 257,355 — — (347) 1,751,451 Earned premiums 1,303,562 264,982 — — (507) 1,568,037 Losses and loss adjustment expenses: Current accident year (783,306) (166,853) — — — (950,159) Prior accident years 154,526 (21,741) — — 2,419 135,204 Underwriting, acquisition and insurance expenses: Amortization of policy acquisition costs (264,823) (67,986) — — — (332,809) Other underwriting expenses (204,622) (13,414) — — 2,481 (215,555) Underwriting profit (loss) 205,337 (5,012) — — 4,393 204,718 Net investment income — — 96,259 2 — 96,261 Net investment gains — — 674,753 — — 674,753 Products revenues — — — 592,601 — 592,601 Services and other revenues — — — 482,903 86,217 569,120 Products expenses — — — (502,202) — (502,202) Services and other expenses — 109 — (450,781) (65,579) (516,251) Amortization of intangible assets (3) — — — (13,858) (25,871) (39,729) Segment profit (loss) $ 205,337 $ (4,903) $ 771,012 $ 108,665 $ (840) $ 1,079,271 Interest expense (46,568) Net foreign exchange losses (12,257) Income before income taxes $ 1,020,446 U.S. GAAP combined ratio (4) 84 % 102 % NM (5) 87 % (1) Products expenses and services and other expenses for the Markel Ventures segment include depreciation expense of $15.8 million for the quarter ended June 30, 2021. (2) Other represents the total profit (loss) attributable to the Company's operations that are not included in a reportable segment as well as any amortization of intangible assets that is not allocated to a reportable segment. Amortization of intangible assets attributable to the Company's underwriting segments was $10.4 million for the quarter ended June 30, 2021, however, the Company does not allocate amortization of intangible assets between the Insurance and Reinsurance segments. (3) Segment profit for the Markel Ventures segment includes amortization of intangible assets attributable to Markel Ventures. Amortization of intangible assets is not allocated to the Company's Insurance and Reinsurance segments. (4) The U.S. GAAP combined ratio is a measure of underwriting performance and represents the relationship of incurred losses, loss adjustment expenses and underwriting, acquisition and insurance expenses to earned premiums. (5) NM - Ratio is not meaningful Six Months Ended June 30, 2022 (dollars in thousands) Insurance Reinsurance Investing Markel Ventures (1) Other (2) Consolidated Gross premium volume $ 4,180,464 $ 865,372 $ — $ — $ 1,632,500 $ 6,678,336 Net written premiums 3,439,182 829,058 — — (3,711) 4,264,529 Earned premiums 3,047,149 548,121 — — (2,396) 3,592,874 Losses and loss adjustment expenses: Current accident year (1,805,520) (348,390) — — — (2,153,910) Prior accident years 142,333 (15,660) — — (3,945) 122,728 Underwriting, acquisition and insurance expenses: Amortization of policy acquisition costs (634,232) (140,879) — — (32) (775,143) Other underwriting expenses (395,822) (26,070) — — (2,799) (424,691) Underwriting profit (loss) 353,908 17,122 — — (9,172) 361,858 Net investment income — — 166,285 107 — 166,392 Net investment losses — — (1,913,042) — — (1,913,042) Products revenues — — — 1,258,580 — 1,258,580 Services and other revenues — — — 1,053,103 240,536 1,293,639 Products expenses — — — (1,145,537) — (1,145,537) Services and other expenses — — — (967,960) (183,674) (1,151,634) Amortization of intangible assets (3) — — — (41,510) (50,062) (91,572) Segment profit (loss) $ 353,908 $ 17,122 $ (1,746,757) $ 156,783 $ (2,372) $ (1,221,316) Interest expense (99,742) Net foreign exchange gains 130,226 Loss before income taxes $ (1,190,832) U.S. GAAP combined ratio (4) 88 % 97 % NM (5) 90 % (1) Products expenses and services and other expenses for the Markel Ventures segment include depreciation expense of $51.6 million for the six months ended June 30, 2022. (2) Other represents the total profit (loss) attributable to the Company's operations that are not included in a reportable segment as well as any amortization of intangible assets that is not allocated to a reportable segment. Amortization of intangible assets attributable to the Company's underwriting segments was $19.4 million for the six months ended June 30, 2022, however, the Company does not allocate amortization of intangible assets between the Insurance and Reinsurance segments. (3) Segment profit for the Markel Ventures segment includes amortization of intangible assets attributable to Markel Ventures. Amortization of intangible assets is not allocated to the Company's Insurance and Reinsurance segments. (4) The U.S. GAAP combined ratio is a measure of underwriting performance and represents the relationship of incurred losses, loss adjustment expenses and underwriting, acquisition and insurance expenses to earned premiums. (5) NM - Ratio is not meaningful Six Months Ended June 30, 2021 (dollars in thousands) Insurance Reinsurance Investing Markel Ventures (1) Other (2) Consolidated Gross premium volume $ 3,459,701 $ 811,962 $ — $ — $ 1,417,202 $ 5,688,865 Net written premiums 2,881,873 751,440 — — (792) 3,632,521 Earned premiums 2,547,589 519,069 — — (926) 3,065,732 Losses and loss adjustment expenses: Current accident year (1,581,553) (339,354) — — — (1,920,907) Prior accident years 273,590 (50,396) — — 2,840 226,034 Underwriting, acquisition and insurance expenses: Amortization of policy acquisition costs (525,422) (129,974) — — — (655,396) Other underwriting expenses (391,919) (27,575) — — (217) (419,711) Underwriting profit (loss) 322,285 (28,230) — — 1,697 295,752 Net investment income — — 192,826 5 — 192,831 Net investment gains — — 1,201,624 — — 1,201,624 Products revenues — — — 921,433 — 921,433 Services and other revenues — — — 860,670 158,676 1,019,346 Products expenses — — — (798,728) — (798,728) Services and other expenses — 109 — (795,689) (132,768) (928,348) Amortization of intangible assets (3) — — — (27,563) (51,719) (79,282) Segment profit (loss) $ 322,285 $ (28,121) $ 1,394,450 $ 160,128 $ (24,114) $ 1,824,628 Interest expense (88,957) Net foreign exchange gains 12,827 Income before income taxes $ 1,748,498 U.S. GAAP combined ratio (4) 87 % 105 % NM (5) 90 % (1) Products expenses and services and other expenses for the Markel Ventures segment include depreciation expense of $31.8 million for the six months ended June 30, 2021. (2) Other represents the total profit (loss) attributable to the Company's operations that are not included in a reportable segment as well as any amortization of intangible assets that is not allocated to a reportable segment. Amortization of intangible assets attributable to the Company's underwriting segments was $20.8 million for the six months ended June 30, 2021, however, the Company does not allocate amortization of intangible assets between the Insurance and Reinsurance segments. (3) Segment profit for the Markel Ventures segment includes amortization of intangible assets attributable to Markel Ventures. Amortization of intangible assets is not allocated to the Company's Insurance and Reinsurance segments. (4) The U.S. GAAP combined ratio is a measure of underwriting performance and represents the relationship of incurred losses, loss adjustment expenses and underwriting, acquisition and insurance expenses to earned premiums. (5) NM - Ratio is not meaningful
Reconciliation Of Segment Assets To The Company's Consolidated Balance Sheets	The following table reconciles segment assets to the Company's consolidated balance sheets. (dollars in thousands) June 30, 2022 December 31, 2021 Segment assets: Investing $ 25,616,813 $ 28,277,801 Underwriting 9,086,833 8,111,316 Markel Ventures 5,195,988 4,958,279 Total segment assets 39,899,634 41,347,396 Other operations 8,047,139 7,129,700 Total assets $ 47,946,773 $ 48,477,096

Investments (Tables)

Investments (Tables)	3 Months Ended	6 Months Ended
	Mar. 31, 2022	Jun. 30, 2022
Investments, Debt and Equity Securities [Abstract]
Available-For-Sale Investments		The following tables summarize the Company's available-for-sale investments. Commercial and residential mortgage-backed securities include securities issued by U.S. government-sponsored enterprises and U.S. government agencies. The net unrealized holding gains (losses) in the tables below are presented before taxes and any reserve deficiency adjustments for life and annuity benefit reserves. See note 9. June 30, 2022 (dollars in thousands) Amortized Gross Gross Estimated Fixed maturity securities: U.S. Treasury securities $ 2,912,268 $ 49 $ (126,339) $ 2,785,978 U.S. government-sponsored enterprises 822,815 1,761 (70,863) 753,713 Obligations of states, municipalities and political subdivisions 3,972,514 26,051 (137,823) 3,860,742 Foreign governments 1,402,054 2,675 (107,950) 1,296,779 Commercial mortgage-backed securities 2,013,800 409 (96,890) 1,917,319 Residential mortgage-backed securities 615,940 1,736 (10,146) 607,530 Asset-backed securities 2,165 — (36) 2,129 Corporate bonds 791,401 409 (72,106) 719,704 Total fixed maturity securities 12,532,957 33,090 (622,153) 11,943,894 Short-term investments 2,064,223 1 (8,690) 2,055,534 Investments, available-for-sale $ 14,597,180 $ 33,091 $ (630,843) $ 13,999,428 December 31, 2021 (dollars in thousands) Amortized Gross Gross Estimated Fixed maturity securities: U.S. Treasury securities $ 2,489,032 $ 2,633 $ (21,471) $ 2,470,194 U.S. government-sponsored enterprises 753,029 28,997 (6,439) 775,587 Obligations of states, municipalities and political subdivisions 4,007,211 266,575 (7,862) 4,265,924 Foreign governments 1,394,771 134,071 (9,488) 1,519,354 Commercial mortgage-backed securities 1,928,775 69,810 (8,152) 1,990,433 Residential mortgage-backed securities 699,136 27,084 (170) 726,050 Asset-backed securities 3,035 46 — 3,081 Corporate bonds 786,478 54,475 (4,271) 836,682 Total fixed maturity securities 12,061,467 583,691 (57,853) 12,587,305 Short-term investments 1,805,300 28 (5,340) 1,799,988 Investments, available-for-sale $ 13,866,767 $ 583,719 $ (63,193) $ 14,387,293
Summary Of Gross Unrealized Investment Losses By Length Of Time That Securities Have Continuously Been In An Unrealized Loss Position	December 31, 2021 Less than 12 months 12 months or longer Total (dollars in thousands) Estimated Gross Estimated Gross Estimated Gross Fixed maturity securities: U.S. Treasury securities $ 2,236,637 $ (18,433) $ 97,173 $ (3,038) $ 2,333,810 $ (21,471) U.S. government-sponsored enterprises 381,495 (5,640) 14,010 (799) 395,505 (6,439) Obligations of states, municipalities and political subdivisions 393,249 (6,941) 23,589 (921) 416,838 (7,862) Foreign governments 322,813 (8,596) 25,564 (892) 348,377 (9,488) Commercial mortgage-backed securities 345,616 (7,765) 9,189 (387) 354,805 (8,152) Residential mortgage-backed securities 12,828 (159) 269 (11) 13,097 (170) Corporate bonds 193,786 (4,271) — — 193,786 (4,271) Total fixed maturity securities 3,886,424 (51,805) 169,794 (6,048) 4,056,218 (57,853) Short-term investments 228,870 (5,340) — — 228,870 (5,340) Total $ 4,115,294 $ (57,145) $ 169,794 $ (6,048) $ 4,285,088 $ (63,193)	The following tables summarize gross unrealized investment losses on available-for-sale investments by the length of time that securities have continuously been in an unrealized loss position. June 30, 2022 Less than 12 months 12 months or longer Total (dollars in thousands) Estimated Gross Estimated Gross Estimated Gross Fixed maturity securities: U.S. Treasury securities $ 1,867,197 $ (81,978) $ 911,928 $ (44,361) $ 2,779,125 $ (126,339) U.S. government-sponsored enterprises 509,765 (45,747) 155,794 (25,116) 665,559 (70,863) Obligations of states, municipalities and political subdivisions 1,951,874 (102,522) 210,370 (35,301) 2,162,244 (137,823) Foreign governments 1,016,734 (94,597) 92,286 (13,353) 1,109,020 (107,950) Commercial mortgage-backed securities 1,743,017 (87,792) 64,010 (9,098) 1,807,027 (96,890) Residential mortgage-backed securities 407,445 (9,614) 4,172 (532) 411,617 (10,146) Asset-backed securities 2,129 (36) — — 2,129 (36) Corporate bonds 614,804 (60,001) 66,422 (12,105) 681,226 (72,106) Total fixed maturity securities 8,112,965 (482,287) 1,504,982 (139,866) 9,617,947 (622,153) Short-term investments 2,034,208 (8,690) — — 2,034,208 (8,690) Total $ 10,147,173 $ (490,977) $ 1,504,982 $ (139,866) $ 11,652,155 $ (630,843)
Schedule Of Amortized Cost And Estimated Fair Value Of Fixed Maturity Securities By Contractual Maturity Date		The amortized cost and estimated fair value of fixed maturity securities at June 30, 2022 are shown below by contractual maturity. (dollars in thousands) Amortized Estimated Due in one year or less $ 1,213,444 $ 1,193,593 Due after one year through five years 3,778,157 3,628,633 Due after five years through ten years 2,877,515 2,672,144 Due after ten years 2,031,936 1,922,546 9,901,052 9,416,916 Commercial mortgage-backed securities 2,013,800 1,917,319 Residential mortgage-backed securities 615,940 607,530 Asset-backed securities 2,165 2,129 Total fixed maturity securities $ 12,532,957 $ 11,943,894
Components Of Net Investment Income		The following table presents the components of net investment income. Quarter Ended June 30, Six Months Ended June 30, (dollars in thousands) 2022 2021 2022 2021 Interest: Tax-exempt municipal bonds $ 13,160 $ 14,102 $ 26,735 $ 29,338 Taxable municipal bonds 17,618 16,421 35,125 32,916 Other taxable bonds 41,142 40,618 81,204 80,013 Short-term investments, including overnight deposits 5,795 874 7,001 1,546 Dividends on equity securities 23,590 19,798 48,327 45,183 Income (loss) from equity method investments (3,247) 9,018 (29,493) 12,943 Other (308) (417) 5,938 (612) 97,750 100,414 174,837 201,327 Investment expenses (4,092) (4,153) (8,445) (8,496) Net investment income $ 93,658 $ 96,261 $ 166,392 $ 192,831
Summary Of Net Investment Gains (Losses) And The Change In Net Unrealized Gains On Available-For-Sale Investments		The following table presents the components of net investment gains (losses) and the change in net unrealized gains (losses) included in other comprehensive income (loss). Gross realized investment gains and losses on fixed maturity securities, short-term investments and other investments were not material to the consolidated financial statements and are presented on a net basis in the following table. Quarter Ended June 30, Six Months Ended June 30, (dollars in thousands) 2022 2021 2022 2021 Fixed maturity securities, short-term investments and other investments: Net realized investment gains (losses) $ (2,259) $ 4,402 $ 3,969 $ 7,811 Equity securities: Change in fair value of securities sold during the period (2,113) 1,345 (19,231) 3,971 Change in fair value of securities held at the end of the period (1,550,271) 669,006 (1,897,780) 1,189,842 Total change in fair value (1,552,384) 670,351 (1,917,011) 1,193,813 Net investment gains (losses) $ (1,554,643) $ 674,753 $ (1,913,042) $ 1,201,624 Change in net unrealized gains (losses) on available-for-sale investments included in other comprehensive income (loss): Fixed maturity securities $ (449,089) $ 62,948 $ (1,114,899) $ (258,284) Short-term investments (9,239) 1,095 (3,377) 1,779 Reserve deficiency adjustment for life and annuity benefit reserves (see note 9) — 929 56,560 50,262 Net increase (decrease) $ (458,328) $ 64,972 $ (1,061,716) $ (206,243)

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2022
Fair Value Disclosures [Abstract]
Balances Of Assets Measured At Fair Value On A Recurring Basis	The following tables present the balances of assets measured at fair value on a recurring basis by level within the fair value hierarchy. June 30, 2022 (dollars in thousands) Level 1 Level 2 Level 3 Total Assets: Investments: Fixed maturity securities, available-for-sale: U.S. Treasury securities $ — $ 2,785,978 $ — $ 2,785,978 U.S. government-sponsored enterprises — 753,713 — 753,713 Obligations of states, municipalities and political subdivisions — 3,860,742 — 3,860,742 Foreign governments — 1,296,779 — 1,296,779 Commercial mortgage-backed securities — 1,917,319 — 1,917,319 Residential mortgage-backed securities — 607,530 — 607,530 Asset-backed securities — 2,129 — 2,129 Corporate bonds — 719,704 — 719,704 Total fixed maturity securities, available-for-sale — 11,943,894 — 11,943,894 Equity securities: Insurance, banks and other financial institutions 2,741,363 — 4,380 2,745,743 Industrial, consumer and all other 4,424,258 — — 4,424,258 Total equity securities 7,165,621 — 4,380 7,170,001 Short-term investments, available-for-sale 1,892,694 162,840 — 2,055,534 Total investments $ 9,058,315 $ 12,106,734 $ 4,380 $ 21,169,429 December 31, 2021 (dollars in thousands) Level 1 Level 2 Level 3 Total Assets: Investments: Fixed maturity securities, available-for-sale: U.S. Treasury securities $ — $ 2,470,194 $ — $ 2,470,194 U.S. government-sponsored enterprises — 775,587 — 775,587 Obligations of states, municipalities and political subdivisions — 4,265,924 — 4,265,924 Foreign governments — 1,519,354 — 1,519,354 Commercial mortgage-backed securities — 1,990,433 — 1,990,433 Residential mortgage-backed securities — 726,050 — 726,050 Asset-backed securities — 3,081 — 3,081 Corporate bonds — 836,682 — 836,682 Total fixed maturity securities, available-for-sale — 12,587,305 — 12,587,305 Equity securities: Insurance, banks and other financial institutions 3,307,755 — 56,472 3,364,227 Industrial, consumer and all other 5,659,700 — — 5,659,700 Total equity securities 8,967,455 — 56,472 9,023,927 Short-term investments, available-for-sale 1,619,496 180,492 — 1,799,988 Total investments $ 10,586,951 $ 12,767,797 $ 56,472 $ 23,411,220
Summary Of Changes In Level 3 Investments Measured At Fair Value On A Recurring Basis	The following table summarizes changes in Level 3 investments measured at fair value on a recurring basis. Quarter Ended June 30, Six Months Ended June 30, (dollars in thousands) 2022 2021 2022 2021 Equity securities, beginning of period $ 8,468 $ 56,138 $ 56,472 $ 58,493 Purchases — — — — Sales (4,027) (15,015) (52,807) (15,015) Net investment gains (losses) (61) (57) 715 (2,412) Equity securities, end of period $ 4,380 $ 41,066 $ 4,380 $ 41,066

Products, Services and Other _2

Products, Services and Other Revenues (Tables)	6 Months Ended
	Jun. 30, 2022
Revenue from Contract with Customer [Abstract]
Schedule Of Revenues From Contracts With Customers By Type	The following tables present revenues from contracts with customers by segment and type, all of which are included in products revenues and services and other revenues in the consolidated statements of income (loss) and comprehensive income (loss), along with a reconciliation to total products revenues and services and other revenues. Quarter Ended June 30, 2022 2021 (dollars in thousands) Markel Ventures Other Total Markel Ventures Other Total Products $ 764,543 $ — $ 764,543 $ 581,321 $ — $ 581,321 Services 569,385 8,450 577,835 468,424 37,902 506,326 Investment management — 20,328 20,328 — 20,785 20,785 Total revenues from contracts with customers 1,333,928 28,778 1,362,706 1,049,745 58,687 1,108,432 Program services and other fronting — 29,731 29,731 — 27,399 27,399 Other 27,370 281 27,651 25,759 131 25,890 Total $ 1,361,298 $ 58,790 $ 1,420,088 $ 1,075,504 $ 86,217 $ 1,161,721 Six Months Ended June 30, 2022 2021 (dollars in thousands) Markel Ventures Other Total Markel Ventures Other Total Products $ 1,233,999 $ — $ 1,233,999 $ 899,963 $ — $ 899,963 Services 1,018,834 30,018 1,048,852 825,112 65,881 890,993 Investment management — 39,556 39,556 — 37,122 37,122 Total revenues from contracts with customers 2,252,833 69,574 2,322,407 1,725,075 103,003 1,828,078 Program services and other fronting — 63,063 63,063 — 55,016 55,016 Disposition gain — 107,293 107,293 — — — Other 58,850 606 59,456 57,028 657 57,685 Total $ 2,311,683 $ 240,536 $ 2,552,219 $ 1,782,103 $ 158,676 $ 1,940,779

Unpaid Losses And Loss Adjust_2

Unpaid Losses And Loss Adjustment Expenses (Tables)	6 Months Ended
	Jun. 30, 2022
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract]
Reconciliation Of Consolidated Reserves For Losses And Loss Adjustment Expenses	The following table presents a reconciliation of consolidated beginning and ending reserves for losses and loss adjustment expenses. Six Months Ended June 30, (dollars in thousands) 2022 2021 Net reserves for losses and loss adjustment expenses, beginning of year $ 11,302,577 $ 10,485,717 Effect of foreign currency rate changes on beginning of year balance (149,383) 5,198 Adjusted net reserves for losses and loss adjustment expenses, beginning of year 11,153,194 10,490,915 Incurred losses and loss adjustment expenses: Current accident year 2,153,910 1,920,907 Prior accident years (122,728) (226,059) Total incurred losses and loss adjustment expenses 2,031,182 1,694,848 Payments: Current accident year 167,262 198,402 Prior accident years 1,291,318 1,190,303 Total payments 1,458,580 1,388,705 Effect of foreign currency rate changes on current year activity 221 (476) Net reserves for losses and loss adjustment expenses of Markel CATCo Re (see note 11) 465,196 — Net reserves for losses and loss adjustment expenses of insurance companies sold — (2,762) Net reserves for losses and loss adjustment expenses, end of period 12,191,213 10,793,820 Reinsurance recoverables on unpaid losses 6,871,547 6,205,996 Gross reserves for losses and loss adjustment expenses, end of period $ 19,062,760 $ 16,999,816

Reinsurance (Tables)

Reinsurance (Tables)	6 Months Ended
	Jun. 30, 2022
Reinsurance Disclosures [Abstract]
Effect Of Reinsurance And Retrocessional Reinsurance On Premiums Written And Earned	The following tables summarize the effect of reinsurance and retrocessional reinsurance on premiums written and earned. Quarter Ended June 30, 2022 2021 (dollars in thousands) Direct Assumed Ceded Net Premiums Direct Assumed Ceded Net Premiums Underwriting: Written $ 2,108,859 $ 420,026 $ (427,959) $ 2,100,926 $ 1,756,680 $ 344,279 $ (349,037) $ 1,751,922 Earned 1,772,695 382,876 (321,438) 1,834,133 1,511,416 351,931 (294,679) 1,568,668 Program services and other fronting: Written 664,590 86,574 (752,295) (1,131) 737,110 45,944 (783,525) (471) Earned 607,099 65,116 (673,244) (1,029) 582,809 23,763 (607,203) (631) Consolidated: Written 2,773,449 506,600 (1,180,254) 2,099,795 2,493,790 390,223 (1,132,562) 1,751,451 Earned $ 2,379,794 $ 447,992 $ (994,682) $ 1,833,104 $ 2,094,225 $ 375,694 $ (901,882) $ 1,568,037 Six Months Ended June 30, 2022 2021 (dollars in thousands) Direct Assumed Ceded Net Premiums Direct Assumed Ceded Net Premiums Underwriting: Written $ 3,932,114 $ 1,116,386 $ (781,341) $ 4,267,159 $ 3,305,777 $ 966,027 $ (638,350) $ 3,633,454 Earned 3,470,665 785,943 (661,367) 3,595,241 2,942,749 717,829 (593,779) 3,066,799 Program services and other fronting: Written 1,361,564 268,272 (1,632,466) (2,630) 1,345,147 71,914 (1,417,994) (933) Earned 1,306,704 113,976 (1,423,047) (2,367) 1,165,969 38,668 (1,205,704) (1,067) Consolidated: Written 5,293,678 1,384,658 (2,413,807) 4,264,529 4,650,924 1,037,941 (2,056,344) 3,632,521 Earned $ 4,777,369 $ 899,919 $ (2,084,414) $ 3,592,874 $ 4,108,718 $ 756,497 $ (1,799,483) $ 3,065,732
Effect Of Reinsurance And Retrocessional Reinsurance On Losses and Loss Adjustment Expenses	The following table summarizes the effect of reinsurance and retrocessional reinsurance on losses and loss adjustment expenses in the Company's underwriting operations. Quarter Ended June 30, Six Months Ended June 30, (dollars in thousands) 2022 2021 2022 2021 Gross losses and loss adjustment expenses $ 1,186,691 $ 993,138 $ 2,337,040 $ 2,067,061 Ceded losses and loss adjustment expenses (127,895) (177,674) (305,889) (369,645) Net losses and loss adjustment expenses $ 1,058,796 $ 815,464 $ 2,031,151 $ 1,697,416

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	6 Months Ended
	Jun. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Amounts attributable to Markel CATCo Re in Markel's consolidated balance sheet	The Company's consolidated balance sheet includes the following amounts attributable to Markel CATCo Re. (dollars in thousands) June 30, 2022 Assets Cash and cash equivalents $ 75,144 Restricted cash and cash equivalents 357,974 Other assets and receivables due from cedents 81,751 Total Assets $ 514,869 Liabilities and Equity Unpaid losses and loss adjustment expenses $ 465,196 Other liabilities 22,596 Total Liabilities 487,792 Shareholders' Equity 21,139 Noncontrolling interests 5,938 Total Equity 27,077 Total Liabilities and Equity $ 514,869

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2022
Stockholders' Equity Note [Abstract]
Schedule of Common Stock Outstanding Roll Forward	The Company has 50,000,000 shares of no par value common stock authorized. The following table presents a rollforward of changes in common shares issued and outstanding. Quarter Ended June 30, Six Months Ended June 30, (in thousands) 2022 2021 2022 2021 Issued and outstanding common shares, beginning of period 13,570 13,765 13,632 13,783 Issuance of common shares 1 2 2 3 Repurchase of common shares (33) (33) (96) (52) Issued and outstanding common shares, end of period 13,538 13,734 13,538 13,734
Schedule Of Net Income (Loss) Per Common Share	The following table presents net income (loss) per common share and diluted net income (loss) per common share. Quarter Ended June 30, Six Months Ended June 30, (in thousands, except per share amounts) 2022 2021 2022 2021 Net income (loss) to common shareholders $ (934,359) $ 774,110 $ (987,202) $ 1,347,804 Adjustment of redeemable noncontrolling interests (7,498) 13,717 (44,438) 21,623 Adjusted net income (loss) to common shareholders $ (941,857) $ 787,827 $ (1,031,640) $ 1,369,427 Basic common shares outstanding 13,612 13,793 13,632 13,806 Dilutive potential common shares from restricted stock units and restricted stock (1) — 24 — 22 Diluted common shares outstanding 13,612 13,817 13,632 13,828 Basic net income (loss) per common share $ (69.19) $ 57.12 $ (75.68) $ 99.19 Diluted net income (loss) per common share (1) $ (69.19) $ 57.02 $ (75.68) $ 99.03 (1) The impact of 31 thousand and 29 thousand shares from restricted stock units and restricted stock was excluded from the computation of diluted net loss per common share for the quarter and six months ended June 30, 2022, respectively, because the effect would have been anti-dilutive.

Segment Reporting Disclosures_2

Segment Reporting Disclosures (Company's Segment Disclosures) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022		Jun. 30, 2021		Jun. 30, 2022		Jun. 30, 2021
Segment Reporting Information [Line Items]
Gross premium volume	$ 3,280,049		$ 2,884,013		$ 6,678,336		$ 5,688,865
Net written premiums	2,099,795		1,751,451		4,264,529		3,632,521
Earned premiums	1,833,104		1,568,037		3,592,874		3,065,732
Losses and loss adjustment expenses, current accident year	(1,085,215)		(950,159)		(2,153,910)		(1,920,907)
Losses and loss adjustment expenses, prior accident year	26,405		135,204		122,728		226,034
Amortization of policy acquisition costs	(392,983)		(332,809)		(775,143)		(655,396)
Other underwriting expenses	(216,486)		(215,555)		(424,691)		(419,711)
Underwriting profit (loss)	164,825		204,718		361,858		295,752
Net investment income	93,658		96,261		166,392		192,831
Net investment gains (losses)	(1,554,643)		674,753		(1,913,042)		1,201,624
Products revenues	776,959		592,601		1,258,580		921,433
Services and other revenues	643,129		569,120		1,293,639		1,019,346
Products expenses	(697,718)		(502,202)		(1,145,537)		(798,728)
Services and other expenses	(559,858)		(516,251)		(1,151,634)		(928,348)
Amortization of intangible assets	(45,523)	[1]	(39,729)	[2]	(91,572)	[3]	(79,282)	[4]
Segment profit (loss)	(1,179,171)		1,079,271		(1,221,316)		1,824,628
Interest expense	(50,050)		(46,568)		(99,742)		(88,957)
Net foreign exchange gains	106,732		(12,257)		130,226		12,827
Income (Loss) before income taxes	$ (1,122,489)		$ 1,020,446		$ (1,190,832)		$ 1,748,498
U.S. GAAP combined ratio	91%	[5]	87%	[6]	90%	[7]	90%	[8]
Insurance [Member]
Segment Reporting Information [Line Items]
Gross premium volume	$ 2,237,158		$ 1,821,374		$ 4,180,464		$ 3,459,701
Net written premiums	1,828,162		1,494,443		3,439,182		2,881,873
Earned premiums	1,570,001		1,303,562		3,047,149		2,547,589
Losses and loss adjustment expenses, current accident year	(919,283)		(783,306)		(1,805,520)		(1,581,553)
Losses and loss adjustment expenses, prior accident year	43,693		154,526		142,333		273,590
Amortization of policy acquisition costs	(323,826)		(264,823)		(634,232)		(525,422)
Other underwriting expenses	(204,171)		(204,622)		(395,822)		(391,919)
Underwriting profit (loss)	166,414		205,337		353,908		322,285
Net investment income	0		0		0		0
Net investment gains (losses)	0		0		0		0
Products revenues	0		0		0		0
Services and other revenues	0		0		0		0
Products expenses	0		0		0		0
Services and other expenses	0		0		0		0
Amortization of intangible assets	0	[1]	0	[2]	0	[3]	0	[4]
Segment profit (loss)	$ 166,414		$ 205,337		$ 353,908		$ 322,285
U.S. GAAP combined ratio	89%	[5]	84%	[6]	88%	[7]	87%	[8]
Reinsurance [Member]
Segment Reporting Information [Line Items]
Gross premium volume	$ 289,056		$ 279,444		$ 865,372		$ 811,962
Net written premiums	273,838		257,355		829,058		751,440
Earned premiums	264,154		264,982		548,121		519,069
Losses and loss adjustment expenses, current accident year	(165,932)		(166,853)		(348,390)		(339,354)
Losses and loss adjustment expenses, prior accident year	(13,577)		(21,741)		(15,660)		(50,396)
Amortization of policy acquisition costs	(69,125)		(67,986)		(140,879)		(129,974)
Other underwriting expenses	(11,681)		(13,414)		(26,070)		(27,575)
Underwriting profit (loss)	3,839		(5,012)		17,122		(28,230)
Net investment income	0		0		0		0
Net investment gains (losses)	0		0		0		0
Products revenues	0		0		0		0
Services and other revenues	0		0		0		0
Products expenses	0		0		0		0
Services and other expenses	0		109		0		109
Amortization of intangible assets	0	[1]	0	[2]	0	[3]	0	[4]
Segment profit (loss)	$ 3,839		$ (4,903)		$ 17,122		$ (28,121)
U.S. GAAP combined ratio	99%	[5]	102%	[6]	97%	[7]	105%	[8]
Investing [Member]
Segment Reporting Information [Line Items]
Gross premium volume	$ 0		$ 0		$ 0		$ 0
Net written premiums	0		0		0		0
Earned premiums	0		0		0		0
Losses and loss adjustment expenses, current accident year	0		0		0		0
Losses and loss adjustment expenses, prior accident year	0		0		0		0
Amortization of policy acquisition costs	0		0		0		0
Other underwriting expenses	0		0		0		0
Underwriting profit (loss)	0		0		0		0
Net investment income	93,558		96,259		166,285		192,826
Net investment gains (losses)	(1,554,643)		674,753		(1,913,042)		1,201,624
Products revenues	0		0		0		0
Services and other revenues	0		0		0		0
Products expenses	0		0		0		0
Services and other expenses	0		0		0		0
Amortization of intangible assets	0	[1]	0	[2]	0	[3]	0	[4]
Segment profit (loss)	(1,461,085)		771,012		(1,746,757)		1,394,450
Markel Ventures [Member]
Segment Reporting Information [Line Items]
Gross premium volume	0	[9]	0	[10]	0	[11]	0	[12]
Net written premiums	0	[9]	0	[10]	0	[11]	0	[12]
Earned premiums	0	[9]	0	[10]	0	[11]	0	[12]
Losses and loss adjustment expenses, current accident year	0	[9]	0	[10]	0	[11]	0	[12]
Losses and loss adjustment expenses, prior accident year	0	[9]	0	[10]	0	[11]	0	[12]
Amortization of policy acquisition costs	0	[9]	0	[10]	0	[11]	0	[12]
Other underwriting expenses	0	[9]	0	[10]	0	[11]	0	[12]
Underwriting profit (loss)	0	[9]	0	[10]	0	[11]	0	[12]
Net investment income	100	[9]	2	[10]	107	[11]	5	[12]
Net investment gains (losses)	0	[9]	0	[10]	0	[11]	0	[12]
Products revenues	776,959	[9]	592,601	[10]	1,258,580	[11]	921,433	[12]
Services and other revenues	584,339	[9]	482,903	[10]	1,053,103	[11]	860,670	[12]
Products expenses	(697,718)	[9]	(502,202)	[10]	(1,145,537)	[11]	(798,728)	[12]
Services and other expenses	(536,057)	[9]	(450,781)	[10]	(967,960)	[11]	(795,689)	[12]
Amortization of intangible assets	(20,577)	[1],[9]	(13,858)	[2],[10]	(41,510)	[3],[11]	(27,563)	[4],[12]
Segment profit (loss)	107,046	[9]	108,665	[10]	156,783	[11]	160,128	[12]
Depreciation	26,500	[9]	15,800	[10]	51,600	[11]	31,800	[12]
Underwriting Segments [Member]
Segment Reporting Information [Line Items]
Amortization of intangible assets	9,600	[13]	10,400	[14]	19,400	[15]	20,800	[16]
Other [Member]
Segment Reporting Information [Line Items]
Gross premium volume	753,835	[13]	783,195	[14]	1,632,500	[15]	1,417,202	[16]
Net written premiums	(2,205)	[13]	(347)	[14]	(3,711)	[15]	(792)	[16]
Earned premiums	(1,051)	[13]	(507)	[14]	(2,396)	[15]	(926)	[16]
Losses and loss adjustment expenses, current accident year	0	[13]	0	[14]	0	[15]	0	[16]
Losses and loss adjustment expenses, prior accident year	(3,711)	[13]	2,419	[14]	(3,945)	[15]	2,840	[16]
Amortization of policy acquisition costs	(32)	[13]	0	[14]	(32)	[15]	0	[16]
Other underwriting expenses	(634)	[13]	2,481	[14]	(2,799)	[15]	(217)	[16]
Underwriting profit (loss)	(5,428)	[13]	4,393	[14]	(9,172)	[15]	1,697	[16]
Net investment income	0	[13]	0	[14]	0	[15]	0	[16]
Net investment gains (losses)	0	[13]	0	[14]	0	[15]	0	[16]
Products revenues	0	[13]	0	[14]	0	[15]	0	[16]
Services and other revenues	58,790	[13]	86,217	[14]	240,536	[15]	158,676	[16]
Products expenses	0	[13]	0	[14]	0	[15]	0	[16]
Services and other expenses	(23,801)	[13]	(65,579)	[14]	(183,674)	[15]	(132,768)	[16]
Amortization of intangible assets	(24,946)	[1],[13]	(25,871)	[2],[14]	(50,062)	[3],[15]	(51,719)	[4],[16]
Segment profit (loss)	$ 4,615	[13]	$ (840)	[14]	$ (2,372)	[15]	$ (24,114)	[12]
[1]Segment profit for the Markel Ventures segment includes amortization of intangible assets attributable to Markel Ventures. Amortization of intangible assets is not allocated to the Company's Insurance and Reinsurance segments.[2]Segment profit for the Markel Ventures segment includes amortization of intangible assets attributable to Markel Ventures. Amortization of intangible assets is not allocated to the Company's Insurance and Reinsurance segments.[3]Segment profit for the Markel Ventures segment includes amortization of intangible assets attributable to Markel Ventures. Amortization of intangible assets is not allocated to the Company's Insurance and Reinsurance segments.[4]Segment profit for the Markel Ventures segment includes amortization of intangible assets attributable to Markel Ventures. Amortization of intangible assets is not allocated to the Company's Insurance and Reinsurance segments.[5]The U.S. GAAP combined ratio is a measure of underwriting performance and represents the relationship of incurred losses, loss adjustment expenses and underwriting, acquisition and insurance expenses to earned premiums.[6]The U.S. GAAP combined ratio is a measure of underwriting performance and represents the relationship of incurred losses, loss adjustment expenses and underwriting, acquisition and insurance expenses to earned premiums.[7]The U.S. GAAP combined ratio is a measure of underwriting performance and represents the relationship of incurred losses, loss adjustment expenses and underwriting, acquisition and insurance expenses to earned premiums.[8]The U.S. GAAP combined ratio is a measure of underwriting performance and represents the relationship of incurred losses, loss adjustment expenses and underwriting, acquisition and insurance expenses to earned premiums.[9]Products expenses and services and other expenses for the Markel Ventures segment include depreciation expense of $26.5 million for the quarter ended June 30, 2022.[10]Products expenses and services and other expenses for the Markel Ventures segment include depreciation expense of $15.8 million for the quarter ended June 30, 2021.[11]Products expenses and services and other expenses for the Markel Ventures segment include depreciation expense of $51.6 million for the six months ended June 30, 2022.[12]Products expenses and services and other expenses for the Markel Ventures segment include depreciation expense of $31.8 million for the six months ended June 30, 2021.[13]Other represents the total profit (loss) attributable to the Company's operations that are not included in a reportable segment as well as any amortization of intangible assets that is not allocated to a reportable segment. Amortization of intangible assets attributable to the Company's underwriting segments was $9.6 million for the quarter ended June 30, 2022, however, the Company does not allocate amortization of intangible assets between the Insurance and Reinsurance segments.[14]Other represents the total profit (loss) attributable to the Company's operations that are not included in a reportable segment as well as any amortization of intangible assets that is not allocated to a reportable segment. Amortization of intangible assets attributable to the Company's underwriting segments was $10.4 million for the quarter ended June 30, 2021, however, the Company does not allocate amortization of intangible assets between the Insurance and Reinsurance segments.[15]Other represents the total profit (loss) attributable to the Company's operations that are not included in a reportable segment as well as any amortization of intangible assets that is not allocated to a reportable segment. Amortization of intangible assets attributable to the Company's underwriting segments was $19.4 million for the six months ended June 30, 2022, however, the Company does not allocate amortization of intangible assets between the Insurance and Reinsurance segments.[16]Other represents the total profit (loss) attributable to the Company's operations that are not included in a reportable segment as well as any amortization of intangible assets that is not allocated to a reportable segment. Amortization of intangible assets attributable to the Company's underwriting segments was $20.8 million for the six months ended June 30, 2021, however, the Company does not allocate amortization of intangible assets between the Insurance and Reinsurance segments.

Segment Reporting Disclosures_3

Segment Reporting Disclosures (Reconciliation Of Segment Assets To The Company's Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Assets	$ 47,946,773	$ 48,477,096
Other [Member]
Segment Reporting Information [Line Items]
Assets	8,047,139	7,129,700
Segment assets [Member]
Segment Reporting Information [Line Items]
Assets	39,899,634	41,347,396
Segment assets [Member] | Investing [Member]
Segment Reporting Information [Line Items]
Assets	25,616,813	28,277,801
Segment assets [Member] | Underwriting [Member]
Segment Reporting Information [Line Items]
Assets	9,086,833	8,111,316
Segment assets [Member] | Markel Ventures [Member]
Segment Reporting Information [Line Items]
Assets	$ 5,195,988	$ 4,958,279

Acquisitions and Dispositions (

Acquisitions and Dispositions (Narratives) (Details) - USD ($) $ in Thousands				6 Months Ended
	Feb. 01, 2022	Dec. 21, 2021	Aug. 31, 2021	Jun. 30, 2022
Velocity [Member]
Schedule of Business Dispositions, by Dispositions [Line Items]
Proceeds from sale of business	$ 181,300
Gain on sale of business	107,300
Business combination, disposition of less than 100 percent, noncontrolling interest, fair value	$ 47,400
Metromont LLC [Member]
Business Acquisition [Line Items]
Percentage acquired		51%
Total purchase consideration		$ 282,300
Cash consideration		$ 282,300
Goodwill, period decrease				$ 18,700
Noncontrolling interest, period decrease				18,700
Goodwill recognized				200,600
Expected tax deductible goodwill				200,600
Intangible Assets				143,900
Redeemable noncontrolling interest				$ 251,200
Buckner HeavyLift Cranes [Member]
Business Acquisition [Line Items]
Percentage acquired			90%
Total purchase consideration			$ 237,900
Cash consideration			237,900
Goodwill recognized			74,500
Expected tax deductible goodwill			0
Finite-lived intangible assets			60,000
Fixed assets			332,600
Long-term debt			165,100
Redeemable noncontrolling interest			26,400
Buckner HeavyLift Cranes [Member] | Customer relationships [Member]
Business Acquisition [Line Items]
Finite-lived intangible assets			$ 50,000
Definite-lived intangible assets, weighted-average amortization period			6 years
Buckner HeavyLift Cranes [Member] | Trade names [Member]
Business Acquisition [Line Items]
Finite-lived intangible assets			$ 10,000
Definite-lived intangible assets, weighted-average amortization period			15 years

Investments (Narrative) (Detail

Investments (Narrative) (Details) $ in Thousands	Jun. 30, 2022 USD ($) securities	Dec. 31, 2021 USD ($) securities
Schedule of Investments [Line Items]
Available-for-sale fixed maturity securities in unrealized loss position, number of positions | securities	1,127	277
Available-for-sale securities, estimated fair value	$ 11,652,155	$ 4,285,088
Available-for-sale securities, gross unrealized holding losses	$ (630,843)	$ (63,193)
Number of available-for-sale fixed maturity securities positions in a continuous unrealized loss position for one year or longer at period end | securities	110	13
Available-for-sale securities, estimated fair value, 12 months or longer	$ 1,504,982	$ 169,794
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(139,866)	(6,048)
Available-for-sale, allowance for credit losses	0	0
Equity method investments	489,400	459,700
Hagerty Group, LLC [Member]
Schedule of Investments [Line Items]
Equity method investments	$ 241,600	$ 256,600
Equity method investment, ownership percentage	23%	23%
Equity method investment, quoted market value	$ 896,200	$ 1,100,000
Fixed Maturities [Member]
Schedule of Investments [Line Items]
Available-for-sale securities, estimated fair value	9,617,947	4,056,218
Available-for-sale securities, gross unrealized holding losses	(622,153)	(57,853)
Available-for-sale securities, estimated fair value, 12 months or longer	1,504,982	169,794
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	$ (139,866)	$ (6,048)

Investments (Available-For-Sale

Investments (Available-For-Sale Investments) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, amortized cost	$ 12,532,957	$ 12,061,467
Available-for-sale fixed maturity investments, gross unrealized holding gains	33,090	583,691
Available-for-sale fixed maturity investments, gross unrealized holding losses	(622,153)	(57,853)
Available-for-sale fixed maturity investments, estimated fair value	11,943,894	12,587,305
Short-term investments, available-for-sale, amortized cost	2,064,223	1,805,300
Short-term investments, available-for-sale, gross unrealized holding gains	1	28
Short-term investments, available-for-sale, gross unrealized holding losses	(8,690)	(5,340)
Short-term investments, available-for-sale, estimated fair value	2,055,534	1,799,988
Investments, available-for-sale, amortized cost	14,597,180	13,866,767
Investments, available-for-sale, gross unrealized holding gains	33,091	583,719
Investments, available-for-sale, gross unrealized holding losses	(630,843)	(63,193)
Investments, available-for-sale, estimated fair value	13,999,428	14,387,293
Available-for-sale securities, estimated fair value, less than 12 months	10,147,173	4,115,294
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(490,977)	(57,145)
Available-for-sale securities, estimated fair value, 12 months or longer	1,504,982	169,794
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(139,866)	(6,048)
Available-for-sale securities, estimated fair value	11,652,155	4,285,088
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(630,843)	(63,193)
U.S. Treasury securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, amortized cost	2,912,268	2,489,032
Available-for-sale fixed maturity investments, gross unrealized holding gains	49	2,633
Available-for-sale fixed maturity investments, gross unrealized holding losses	(126,339)	(21,471)
Available-for-sale fixed maturity investments, estimated fair value	2,785,978	2,470,194
Available-for-sale securities, estimated fair value, less than 12 months	1,867,197	2,236,637
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(81,978)	(18,433)
Available-for-sale securities, estimated fair value, 12 months or longer	911,928	97,173
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(44,361)	(3,038)
Available-for-sale securities, estimated fair value	2,779,125	2,333,810
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(126,339)	(21,471)
U.S. government-sponsored enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, amortized cost	822,815	753,029
Available-for-sale fixed maturity investments, gross unrealized holding gains	1,761	28,997
Available-for-sale fixed maturity investments, gross unrealized holding losses	(70,863)	(6,439)
Available-for-sale fixed maturity investments, estimated fair value	753,713	775,587
Available-for-sale securities, estimated fair value, less than 12 months	509,765	381,495
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(45,747)	(5,640)
Available-for-sale securities, estimated fair value, 12 months or longer	155,794	14,010
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(25,116)	(799)
Available-for-sale securities, estimated fair value	665,559	395,505
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(70,863)	(6,439)
Obligations of states, municipalities and political subdivisions [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, amortized cost	3,972,514	4,007,211
Available-for-sale fixed maturity investments, gross unrealized holding gains	26,051	266,575
Available-for-sale fixed maturity investments, gross unrealized holding losses	(137,823)	(7,862)
Available-for-sale fixed maturity investments, estimated fair value	3,860,742	4,265,924
Available-for-sale securities, estimated fair value, less than 12 months	1,951,874	393,249
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(102,522)	(6,941)
Available-for-sale securities, estimated fair value, 12 months or longer	210,370	23,589
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(35,301)	(921)
Available-for-sale securities, estimated fair value	2,162,244	416,838
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(137,823)	(7,862)
Foreign governments [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, amortized cost	1,402,054	1,394,771
Available-for-sale fixed maturity investments, gross unrealized holding gains	2,675	134,071
Available-for-sale fixed maturity investments, gross unrealized holding losses	(107,950)	(9,488)
Available-for-sale fixed maturity investments, estimated fair value	1,296,779	1,519,354
Available-for-sale securities, estimated fair value, less than 12 months	1,016,734	322,813
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(94,597)	(8,596)
Available-for-sale securities, estimated fair value, 12 months or longer	92,286	25,564
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(13,353)	(892)
Available-for-sale securities, estimated fair value	1,109,020	348,377
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(107,950)	(9,488)
Commercial mortgage-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, amortized cost	2,013,800	1,928,775
Available-for-sale fixed maturity investments, gross unrealized holding gains	409	69,810
Available-for-sale fixed maturity investments, gross unrealized holding losses	(96,890)	(8,152)
Available-for-sale fixed maturity investments, estimated fair value	1,917,319	1,990,433
Available-for-sale securities, estimated fair value, less than 12 months	1,743,017	345,616
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(87,792)	(7,765)
Available-for-sale securities, estimated fair value, 12 months or longer	64,010	9,189
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(9,098)	(387)
Available-for-sale securities, estimated fair value	1,807,027	354,805
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(96,890)	(8,152)
Residential mortgage-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, amortized cost	615,940	699,136
Available-for-sale fixed maturity investments, gross unrealized holding gains	1,736	27,084
Available-for-sale fixed maturity investments, gross unrealized holding losses	(10,146)	(170)
Available-for-sale fixed maturity investments, estimated fair value	607,530	726,050
Available-for-sale securities, estimated fair value, less than 12 months	407,445	12,828
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(9,614)	(159)
Available-for-sale securities, estimated fair value, 12 months or longer	4,172	269
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(532)	(11)
Available-for-sale securities, estimated fair value	411,617	13,097
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(10,146)	(170)
Asset-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, amortized cost	2,165	3,035
Available-for-sale fixed maturity investments, gross unrealized holding gains	0	46
Available-for-sale fixed maturity investments, gross unrealized holding losses	(36)	0
Available-for-sale fixed maturity investments, estimated fair value	2,129	3,081
Available-for-sale securities, estimated fair value, less than 12 months	2,129
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(36)
Available-for-sale securities, estimated fair value, 12 months or longer	0
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	0
Available-for-sale securities, estimated fair value	2,129
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(36)
Corporate bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, amortized cost	791,401	786,478
Available-for-sale fixed maturity investments, gross unrealized holding gains	409	54,475
Available-for-sale fixed maturity investments, gross unrealized holding losses	(72,106)	(4,271)
Available-for-sale fixed maturity investments, estimated fair value	719,704	836,682
Available-for-sale securities, estimated fair value, less than 12 months	614,804	193,786
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(60,001)	(4,271)
Available-for-sale securities, estimated fair value, 12 months or longer	66,422	0
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(12,105)	0
Available-for-sale securities, estimated fair value	681,226	193,786
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(72,106)	(4,271)
Total fixed maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	8,112,965	3,886,424
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(482,287)	(51,805)
Available-for-sale securities, estimated fair value, 12 months or longer	1,504,982	169,794
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(139,866)	(6,048)
Available-for-sale securities, estimated fair value	9,617,947	4,056,218
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ (622,153)	$ (57,853)

Investments (Summary Of Gross U

Investments (Summary Of Gross Unrealized Investment Losses By Length Of Time That Securities Have Continuously Been In An Unrealized Loss Position) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	$ 10,147,173	$ 4,115,294
Available-for-sale securities, gross unrealized holding losses, less than 12 months	(490,977)	(57,145)
Available-for-sale securities, estimated fair value, 12 months or longer	1,504,982	169,794
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(139,866)	(6,048)
Available-for-sale securities, estimated fair value	11,652,155	4,285,088
Available-for-sale securities, gross unrealized holding losses	(630,843)	(63,193)
Short-term investments, estimated fair value, less than 12 months	2,034,208	228,870
Short-term investments, gross unrealized holding losses, less than 12 months	(8,690)	(5,340)
Short-term investments, estimated fair value, 12 months or longer	0	0
Short-term investments, gross unrealized holding losses, 12 months or longer	0	0
Short-term investments, estimated fair value	2,034,208	228,870
Short-term investments, gross unrealized holding losses	(8,690)	(5,340)
U.S. Treasury securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	1,867,197	2,236,637
Available-for-sale securities, gross unrealized holding losses, less than 12 months	(81,978)	(18,433)
Available-for-sale securities, estimated fair value, 12 months or longer	911,928	97,173
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(44,361)	(3,038)
Available-for-sale securities, estimated fair value	2,779,125	2,333,810
Available-for-sale securities, gross unrealized holding losses	(126,339)	(21,471)
U.S. government-sponsored enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	509,765	381,495
Available-for-sale securities, gross unrealized holding losses, less than 12 months	(45,747)	(5,640)
Available-for-sale securities, estimated fair value, 12 months or longer	155,794	14,010
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(25,116)	(799)
Available-for-sale securities, estimated fair value	665,559	395,505
Available-for-sale securities, gross unrealized holding losses	(70,863)	(6,439)
Obligations of states, municipalities and political subdivisions [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	1,951,874	393,249
Available-for-sale securities, gross unrealized holding losses, less than 12 months	(102,522)	(6,941)
Available-for-sale securities, estimated fair value, 12 months or longer	210,370	23,589
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(35,301)	(921)
Available-for-sale securities, estimated fair value	2,162,244	416,838
Available-for-sale securities, gross unrealized holding losses	(137,823)	(7,862)
Foreign governments [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	1,016,734	322,813
Available-for-sale securities, gross unrealized holding losses, less than 12 months	(94,597)	(8,596)
Available-for-sale securities, estimated fair value, 12 months or longer	92,286	25,564
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(13,353)	(892)
Available-for-sale securities, estimated fair value	1,109,020	348,377
Available-for-sale securities, gross unrealized holding losses	(107,950)	(9,488)
Commercial mortgage-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	1,743,017	345,616
Available-for-sale securities, gross unrealized holding losses, less than 12 months	(87,792)	(7,765)
Available-for-sale securities, estimated fair value, 12 months or longer	64,010	9,189
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(9,098)	(387)
Available-for-sale securities, estimated fair value	1,807,027	354,805
Available-for-sale securities, gross unrealized holding losses	(96,890)	(8,152)
Residential mortgage-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	407,445	12,828
Available-for-sale securities, gross unrealized holding losses, less than 12 months	(9,614)	(159)
Available-for-sale securities, estimated fair value, 12 months or longer	4,172	269
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(532)	(11)
Available-for-sale securities, estimated fair value	411,617	13,097
Available-for-sale securities, gross unrealized holding losses	(10,146)	(170)
Corporate bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	614,804	193,786
Available-for-sale securities, gross unrealized holding losses, less than 12 months	(60,001)	(4,271)
Available-for-sale securities, estimated fair value, 12 months or longer	66,422	0
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(12,105)	0
Available-for-sale securities, estimated fair value	681,226	193,786
Available-for-sale securities, gross unrealized holding losses	(72,106)	(4,271)
Total fixed maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	8,112,965	3,886,424
Available-for-sale securities, gross unrealized holding losses, less than 12 months	(482,287)	(51,805)
Available-for-sale securities, estimated fair value, 12 months or longer	1,504,982	169,794
Available-for-sale securities, gross unrealized holding losses, 12 months or longer	(139,866)	(6,048)
Available-for-sale securities, estimated fair value	9,617,947	4,056,218
Available-for-sale securities, gross unrealized holding losses	$ (622,153)	$ (57,853)

Investments (Schedule Of Amorti

Investments (Schedule Of Amortized Cost And Estimated Fair Value Of Fixed Maturity Securities By Contractual Maturity Date) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Due in one year or less, amortized cost	$ 1,213,444
Due after one year through five years, amortized cost	3,778,157
Due after five years through ten years, amortized cost	2,877,515
Due after ten years, amortized cost	2,031,936
Amortized cost, sub-total	9,901,052
Total fixed maturities, amortized cost	12,532,957	$ 12,061,467
Due in one year or less, estimated fair value	1,193,593
Due after one year through five years, estimated fair value	3,628,633
Due after five years through ten years, estimated fair value	2,672,144
Due after ten years, estimated fair value	1,922,546
Estimated fair value, sub-total	9,416,916
Total fixed maturities, estimated fair value	11,943,894	12,587,305
Commercial mortgage-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, amortized cost	2,013,800
Total fixed maturities, amortized cost	2,013,800	1,928,775
Fixed maturities, estimated fair value	1,917,319
Total fixed maturities, estimated fair value	1,917,319	1,990,433
Residential mortgage-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, amortized cost	615,940
Total fixed maturities, amortized cost	615,940	699,136
Fixed maturities, estimated fair value	607,530
Total fixed maturities, estimated fair value	607,530	726,050
Asset-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, amortized cost	2,165
Total fixed maturities, amortized cost	2,165	3,035
Fixed maturities, estimated fair value	2,129
Total fixed maturities, estimated fair value	$ 2,129	$ 3,081

Investments (Components Of Net

Investments (Components Of Net Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Tax-exempt municipal bonds	$ 13,160	$ 14,102	$ 26,735	$ 29,338
Short-term investments, including overnight deposits	5,795	874	7,001	1,546
Dividends on equity securities	23,590	19,798	48,327	45,183
Income (loss) from equity method investments	(3,247)	9,018	(29,493)	12,943
Other	308	417	(5,938)	612
Total investment income	97,750	100,414	174,837	201,327
Investment expenses	(4,092)	(4,153)	(8,445)	(8,496)
Net investment income	93,658	96,261	166,392	192,831
Taxable municipal bonds [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Taxable bonds	17,618	16,421	35,125	32,916
Other taxable bonds [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Taxable bonds	$ 41,142	$ 40,618	$ 81,204	$ 80,013

Investments (Summary Of Net Inv

Investments (Summary Of Net Investment Gains (Losses) And The Change In Net Unrealized Gains On Investments) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Gain (Loss) on Securities [Line Items]
Net realized investment gains (losses)	$ (2,259)	$ 4,402	$ 3,969	$ 7,811
Equity securities, Change in fair value of securities sold during the period	(2,113)	1,345	(19,231)	3,971
Equity securities, Change in fair value of securities held at the end of the period	(1,550,271)	669,006	(1,897,780)	1,189,842
Total change in fair value of equity securities	(1,552,384)	670,351	(1,917,011)	1,193,813
Net investment gains (losses)	(1,554,643)	674,753	(1,913,042)	1,201,624
Change in net unrealized gains on available-for-sale investments included in other comprehensive income	(458,328)	64,972	(1,061,716)	(206,243)
Reserve deficiency adjustment for life and annuity benefit reserves	0	929	56,560	50,262
Fixed Maturities [Member]
Gain (Loss) on Securities [Line Items]
Change in net unrealized gains on available-for-sale investments included in other comprehensive income	(449,089)	62,948	(1,114,899)	(258,284)
Short-term investments [Member]
Gain (Loss) on Securities [Line Items]
Change in net unrealized gains on available-for-sale investments included in other comprehensive income	$ (9,239)	$ 1,095	$ (3,377)	$ 1,779

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net investment gains (losses)	$ (1,554,643)	$ 674,753	$ (1,913,042)	$ 1,201,624
Equity securities	7,170,001		7,170,001		$ 9,023,927
Purchases	0	0	0	0
Sales	(4,027)	(15,015)	(52,807)	(15,015)
Unconsolidated Markel CATCo Fund 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Sales			(41,300)
Fair value, recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, level 1 to level 2 transfers, amount			0	0
Fair value, level 2 to level 1 transfers, amount			0	0
Equity securities	7,170,001		7,170,001		$ 9,023,927
Fair value, nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value on a nonrecurring basis	0	0	0	0
Liabilities measured at fair value on a nonrecurring basis	$ 0	$ 0	$ 0	$ 0

Fair Value Measurements (Balanc

Fair Value Measurements (Balances Of Assets Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	$ 11,943,894	$ 12,587,305
Equity securities	7,170,001	9,023,927
Short-term investments, available-for-sale	2,055,534	1,799,988
Total Investments	21,169,429	23,411,220
U.S. Treasury securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	2,785,978	2,470,194
U.S. government-sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	753,713	775,587
Obligations of states, municipalities and political subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	3,860,742	4,265,924
Foreign governments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	1,296,779	1,519,354
Commercial mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	1,917,319	1,990,433
Residential mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	607,530	726,050
Asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	2,129	3,081
Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	719,704	836,682
Fair value, recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	11,943,894	12,587,305
Equity securities	7,170,001	9,023,927
Short-term investments, available-for-sale	2,055,534	1,799,988
Total Investments	21,169,429	23,411,220
Fair value, recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	0	0
Equity securities	7,165,621	8,967,455
Short-term investments, available-for-sale	1,892,694	1,619,496
Total Investments	9,058,315	10,586,951
Fair value, recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	11,943,894	12,587,305
Equity securities	0	0
Short-term investments, available-for-sale	162,840	180,492
Total Investments	12,106,734	12,767,797
Fair value, recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	0	0
Equity securities	4,380	56,472
Short-term investments, available-for-sale	0	0
Total Investments	4,380	56,472
Fair value, recurring [Member] | U.S. Treasury securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	2,785,978	2,470,194
Fair value, recurring [Member] | U.S. Treasury securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	0	0
Fair value, recurring [Member] | U.S. Treasury securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	2,785,978	2,470,194
Fair value, recurring [Member] | U.S. Treasury securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	0	0
Fair value, recurring [Member] | U.S. government-sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	753,713	775,587
Fair value, recurring [Member] | U.S. government-sponsored enterprises [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	0	0
Fair value, recurring [Member] | U.S. government-sponsored enterprises [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	753,713	775,587
Fair value, recurring [Member] | U.S. government-sponsored enterprises [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	0	0
Fair value, recurring [Member] | Obligations of states, municipalities and political subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	3,860,742	4,265,924
Fair value, recurring [Member] | Obligations of states, municipalities and political subdivisions [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	0	0
Fair value, recurring [Member] | Obligations of states, municipalities and political subdivisions [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	3,860,742	4,265,924
Fair value, recurring [Member] | Obligations of states, municipalities and political subdivisions [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	0	0
Fair value, recurring [Member] | Foreign governments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	1,296,779	1,519,354
Fair value, recurring [Member] | Foreign governments [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	0	0
Fair value, recurring [Member] | Foreign governments [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	1,296,779	1,519,354
Fair value, recurring [Member] | Foreign governments [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	0	0
Fair value, recurring [Member] | Commercial mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	1,917,319	1,990,433
Fair value, recurring [Member] | Commercial mortgage-backed securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	0	0
Fair value, recurring [Member] | Commercial mortgage-backed securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	1,917,319	1,990,433
Fair value, recurring [Member] | Commercial mortgage-backed securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	0	0
Fair value, recurring [Member] | Residential mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	607,530	726,050
Fair value, recurring [Member] | Residential mortgage-backed securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	0	0
Fair value, recurring [Member] | Residential mortgage-backed securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	607,530	726,050
Fair value, recurring [Member] | Residential mortgage-backed securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	0	0
Fair value, recurring [Member] | Asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	2,129	3,081
Fair value, recurring [Member] | Asset-backed securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	0	0
Fair value, recurring [Member] | Asset-backed securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	2,129	3,081
Fair value, recurring [Member] | Asset-backed securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	0	0
Fair value, recurring [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	719,704	836,682
Fair value, recurring [Member] | Corporate bonds [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	0	0
Fair value, recurring [Member] | Corporate bonds [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	719,704	836,682
Fair value, recurring [Member] | Corporate bonds [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale fixed maturity investments, estimated fair value	0	0
Fair value, recurring [Member] | Insurance, banks and other financial institutions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	2,745,743	3,364,227
Fair value, recurring [Member] | Insurance, banks and other financial institutions [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	2,741,363	3,307,755
Fair value, recurring [Member] | Insurance, banks and other financial institutions [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	0	0
Fair value, recurring [Member] | Insurance, banks and other financial institutions [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	4,380	56,472
Fair value, recurring [Member] | Industrial, consumer and all other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	4,424,258	5,659,700
Fair value, recurring [Member] | Industrial, consumer and all other [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	4,424,258	5,659,700
Fair value, recurring [Member] | Industrial, consumer and all other [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	0	0
Fair value, recurring [Member] | Industrial, consumer and all other [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	$ 0	$ 0

Fair Value Measurements (Summar

Fair Value Measurements (Summary Of Changes In Level 3 Investments Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, beginning of period	$ 8,468	$ 56,138	$ 56,472	$ 58,493
Purchases	0	0	0	0
Sales	(4,027)	(15,015)	(52,807)	(15,015)
Net investment gains (losses) on Level 3 investments	(61)	(57)	715	(2,412)
Equity securities, end of period	$ 4,380	$ 41,066	4,380	$ 41,066
Unconsolidated Markel CATCo Fund 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Sales			$ (41,300)

Products, Services and Other _3

Products, Services and Other Revenues (Schedule Of Revenues From Contracts With Customers By Type) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue [Line Items]
Other revenues	$ 1,420,088	$ 1,161,721	$ 2,552,219	$ 1,940,779
Revenue from contracts with customers [Member]
Disaggregation of Revenue [Line Items]
Other revenues	1,362,706	1,108,432	2,322,407	1,828,078
Products [Member] | Revenue from contracts with customers [Member]
Disaggregation of Revenue [Line Items]
Other revenues	764,543	581,321	1,233,999	899,963
Services [Member] | Revenue from contracts with customers [Member]
Disaggregation of Revenue [Line Items]
Other revenues	577,835	506,326	1,048,852	890,993
Investment management [Member] | Revenue from contracts with customers [Member]
Disaggregation of Revenue [Line Items]
Other revenues	20,328	20,785	39,556	37,122
Program services and other fronting [Member]
Disaggregation of Revenue [Line Items]
Other revenues	29,731	27,399	63,063	55,016
Disposition gain
Disaggregation of Revenue [Line Items]
Other revenues			107,293	0
Other [Member]
Disaggregation of Revenue [Line Items]
Other revenues	27,651	25,890	59,456	57,685
Markel Ventures [Member]
Disaggregation of Revenue [Line Items]
Other revenues	1,361,298	1,075,504	2,311,683	1,782,103
Markel Ventures [Member] | Revenue from contracts with customers [Member]
Disaggregation of Revenue [Line Items]
Other revenues	1,333,928	1,049,745	2,252,833	1,725,075
Markel Ventures [Member] | Products [Member] | Revenue from contracts with customers [Member]
Disaggregation of Revenue [Line Items]
Other revenues	764,543	581,321	1,233,999	899,963
Markel Ventures [Member] | Services [Member] | Revenue from contracts with customers [Member]
Disaggregation of Revenue [Line Items]
Other revenues	569,385	468,424	1,018,834	825,112
Markel Ventures [Member] | Investment management [Member] | Revenue from contracts with customers [Member]
Disaggregation of Revenue [Line Items]
Other revenues	0	0	0	0
Markel Ventures [Member] | Program services and other fronting [Member]
Disaggregation of Revenue [Line Items]
Other revenues	0	0	0	0
Markel Ventures [Member] | Disposition gain
Disaggregation of Revenue [Line Items]
Other revenues			0	0
Markel Ventures [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Other revenues	27,370	25,759	58,850	57,028
Other [Member]
Disaggregation of Revenue [Line Items]
Other revenues	58,790	86,217	240,536	158,676
Other [Member] | Revenue from contracts with customers [Member]
Disaggregation of Revenue [Line Items]
Other revenues	28,778	58,687	69,574	103,003
Other [Member] | Products [Member] | Revenue from contracts with customers [Member]
Disaggregation of Revenue [Line Items]
Other revenues	0	0	0	0
Other [Member] | Services [Member] | Revenue from contracts with customers [Member]
Disaggregation of Revenue [Line Items]
Other revenues	8,450	37,902	30,018	65,881
Other [Member] | Investment management [Member] | Revenue from contracts with customers [Member]
Disaggregation of Revenue [Line Items]
Other revenues	20,328	20,785	39,556	37,122
Other [Member] | Program services and other fronting [Member]
Disaggregation of Revenue [Line Items]
Other revenues	29,731	27,399	63,063	55,016
Other [Member] | Disposition gain
Disaggregation of Revenue [Line Items]
Other revenues			107,293	0
Other [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Other revenues	$ 281	$ 131	$ 606	$ 657

Products, Services and Other _4

Products, Services and Other Revenues (Schedule Of Receivables And Customer Deposits Related To Contracts With Customers) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Contracts with customers [Member]
Receivables [Line Items]
Trade and Other Receivables, Net	$ 723	$ 626.1

Unpaid Losses And Loss Adjust_3

Unpaid Losses And Loss Adjustment Expenses (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expenses, current accident years	$ 1,085,215	$ 950,159	$ 2,153,910	$ 1,920,907
Favorable (adverse) development on prior years' loss reserves			122,728	226,059
2021 Catastrophes [Member]
Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expenses, current accident years				67,900
Russia-Ukraine conflict
Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expenses, current accident years			35,000
Ceded losses			70,000
Insurance [Member]
Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expenses, current accident years	919,283	783,306	1,805,520	1,581,553
Insurance [Member] | Property Marine and Energy Workers' Comp and Programs Insurance Segment
Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Favorable (adverse) development on prior years' loss reserves			123,300
Insurance [Member] | General Liab Workers Comp Marine and Energy Property and Professional Liab Insurance Segment
Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Favorable (adverse) development on prior years' loss reserves				213,300
Reinsurance [Member]
Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expenses, current accident years	$ 165,932	$ 166,853	$ 348,390	339,354
Reinsurance [Member] | COVID-19 Reinsurance Segment
Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Favorable (adverse) development on prior years' loss reserves				$ (32,800)

Unpaid Losses And Loss Adjust_4

Unpaid Losses And Loss Adjustment Expenses (Reconciliation Of Consolidated Reserves For Losses And Loss Adjustment Expenses) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract]
Net reserves for losses and loss adjustment expenses, beginning of year			$ 11,302,577	$ 10,485,717
Effect of foreign currency rate changes on beginning of year balance	$ (149,383)	$ 5,198	(149,383)	5,198
Adjusted net reserves for losses and loss adjustment expenses, beginning of year			11,153,194	10,490,915
Incurred losses and loss adjustment expenses, current accident years	1,085,215	950,159	2,153,910	1,920,907
Incurred losses and loss adjustment expenses, prior accident years			(122,728)	(226,059)
Total incurred losses and loss adjustment expenses			2,031,182	1,694,848
Payments, current accident year			167,262	198,402
Payments, prior accident years			1,291,318	1,190,303
Total payments			1,458,580	1,388,705
Effect of foreign currency rate changes on current year activity			221	(476)
Net reserves for losses and loss adjustment expenses of Markel CATCo Re			465,196	0
Net reserves for losses and loss adjustment expenses of insurance companies sold			0	(2,762)
Net reserves for losses and loss adjustment expenses, end of period	12,191,213	10,793,820	12,191,213	10,793,820
Reinsurance recoverable on unpaid losses	6,871,547	6,205,996	6,871,547	6,205,996
Gross reserves for losses and loss adjustment expenses, end of period	$ 19,062,760	$ 16,999,816	$ 19,062,760	$ 16,999,816

Reinsurance (Narrative) (Detail

Reinsurance (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Percentage of ceded earned premiums to gross earned premiums	35%	37%	37%	37%
Percentage of assumed earned premiums to net earned premiums	24%	24%	25%	25%
Underwriting [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Gross losses and loss adjustment expenses	$ 1,186,691	$ 993,138	$ 2,337,040	$ 2,067,061
Ceded losses	127,895	177,674	305,889	369,645
Program services and other fronting [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Gross losses and loss adjustment expenses	574,800	636,800	990,500	1,100,000
Ceded losses	$ (574,800)	$ (637,300)	$ (990,500)	$ (1,100,000)

Reinsurance (Effect Of Reinsura

Reinsurance (Effect Of Reinsurance And Retrocessional Reinsurance On Premiums Written And Earned) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Effects of Reinsurance [Line Items]
Direct premiums written	$ 2,773,449	$ 2,493,790	$ 5,293,678	$ 4,650,924
Direct premiums earned	2,379,794	2,094,225	4,777,369	4,108,718
Assumed premiums written	506,600	390,223	1,384,658	1,037,941
Assumed premiums earned	447,992	375,694	899,919	756,497
Ceded premiums written	(1,180,254)	(1,132,562)	(2,413,807)	(2,056,344)
Ceded premiums earned	(994,682)	(901,882)	(2,084,414)	(1,799,483)
Net premiums written	2,099,795	1,751,451	4,264,529	3,632,521
Net premiums earned	1,833,104	1,568,037	3,592,874	3,065,732
Program services and other fronting [Member]
Effects of Reinsurance [Line Items]
Direct premiums written	664,590	737,110	1,361,564	1,345,147
Direct premiums earned	607,099	582,809	1,306,704	1,165,969
Assumed premiums written	86,574	45,944	268,272	71,914
Assumed premiums earned	65,116	23,763	113,976	38,668
Ceded premiums written	(752,295)	(783,525)	(1,632,466)	(1,417,994)
Ceded premiums earned	(673,244)	(607,203)	(1,423,047)	(1,205,704)
Net premiums written	(1,131)	(471)	(2,630)	(933)
Net premiums earned	(1,029)	(631)	(2,367)	(1,067)
Underwriting [Member]
Effects of Reinsurance [Line Items]
Direct premiums written	2,108,859	1,756,680	3,932,114	3,305,777
Direct premiums earned	1,772,695	1,511,416	3,470,665	2,942,749
Assumed premiums written	420,026	344,279	1,116,386	966,027
Assumed premiums earned	382,876	351,931	785,943	717,829
Ceded premiums written	(427,959)	(349,037)	(781,341)	(638,350)
Ceded premiums earned	(321,438)	(294,679)	(661,367)	(593,779)
Net premiums written	2,100,926	1,751,922	4,267,159	3,633,454
Net premiums earned	$ 1,834,133	$ 1,568,668	$ 3,595,241	$ 3,066,799

Reinsurance Reinsurance (Effect

Reinsurance Reinsurance (Effect Of Reinsurance And Retrocessional Reinsurance On Losses) (Details) - Underwriting [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Effects of Reinsurance [Line Items]
Gross losses and loss adjustment expenses	$ 1,186,691	$ 993,138	$ 2,337,040	$ 2,067,061
Ceded losses and loss adjustment expenses	(127,895)	(177,674)	(305,889)	(369,645)
Net losses and loss adjustment expenses	$ 1,058,796	$ 815,464	$ 2,031,151	$ 1,697,416

Life and Annuity Benefits Lif_2

Life and Annuity Benefits Life and Annuity Benefits (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Liability for Future Policy Benefit, before Reinsurance [Abstract]
Cumulative adjustment to life and annuity benefits	$ 0		$ 0		$ 56.6
Adjustment to life and annuity benefits	$ 0	$ (0.9)	$ (56.6)	$ (50.3)

Debt (Details)

Debt (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Line of Credit Facility [Line Items]
Line of Credit Facility, Initiation Date	Apr. 10, 2019
Line of Credit Facility, Expiration Date	Apr. 10, 2024
Senior Notes | Four point nine zero percent unsecured senior notes due July 1, 2022
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.90%
Debt Instrument, Face Amount	$ 350
Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	300
Long-term Line of Credit	0	$ 0
Line of Credit Facility, Increase (Decrease), Net	200
Revolving Credit Facility | Markel Ventures [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	600
Long-term Line of Credit	296.1	$ 94.3
Revolving Credit Facility | Secured Letters of Credit
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 200

Variable Interest Entities (Nar

Variable Interest Entities (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2022	Mar. 31, 2022
Variable Interest Entity [Line Items]
Tail risk cover in Markel CATCo transaction	$ 142.7
Cash funding used to purchase Markel CATCo Funds' interests in Markel CATCo Re		$ 45.1
Returned capital from Markel CATCo Re	24.9
Investment in Markel CATCo Re	$ 20.1
Percentage of Markel CATCo Re net equity held by the Company	74%

Variable Interest Entities (Det

Variable Interest Entities (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 3,698,854	$ 3,978,490
Restricted cash and cash equivalents	1,212,463	902,457
Total Assets	47,946,773	48,477,096
Unpaid losses and loss adjustment expenses	19,062,760	18,178,894	$ 16,999,816
Other liabilities	3,301,497	3,832,084
Total Liabilities	34,684,063	33,275,508
Shareholders' Equity	12,756,207	14,717,350
Noncontrolling interests	11,125	22,860
Total Equity	12,767,332	14,740,210
Total Liabilities and Equity	47,946,773	$ 48,477,096
Markel CatCo Re
Variable Interest Entity [Line Items]
Cash and cash equivalents	75,144
Restricted cash and cash equivalents	357,974
Other assets and receivables due from cedents	81,751
Total Assets	514,869
Unpaid losses and loss adjustment expenses	465,196
Other liabilities	22,596
Total Liabilities	487,792
Shareholders' Equity	21,139
Noncontrolling interests	5,938
Total Equity	27,077
Total Liabilities and Equity	$ 514,869

Related Party Transactions Re_2

Related Party Transactions Related Party Transactions (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Related Party Transaction [Line Items]
Services and other revenues	$ 643,129	$ 569,120	$ 1,293,639	$ 1,019,346
Gross premium volume	3,280,049	2,884,013	6,678,336	5,688,865
Reinsurance recoverables	7,315,657		7,315,657		$ 7,293,555
Ceded premiums written	1,180,254	1,132,562	2,413,807	2,056,344
Syndicate 2357 and certain other Nephila Reinsurers [Member]
Related Party Transaction [Line Items]
Gross premium volume	317,700	186,700	633,300	304,000
Reinsurance recoverables	598,000		598,000		$ 751,000
Ceded premiums written	317,700	186,700	633,300	304,000
Hagerty Group, LLC [Member]
Related Party Transaction [Line Items]
Gross premium volume	204,400	177,600	343,400	297,500
Ceded premiums written	135,200	100,900	227,300	168,800
Insurance-linked Securities Operations [Member] | Unconsolidated entities managed by Nephila [Member]
Related Party Transaction [Line Items]
Services and other revenues	$ 17,500	$ 42,000	$ 39,900	$ 70,700

Shareholders' Equity (Details)

Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Earnings Per Share [Line Items]
Common stock, shares authorized	50,000,000		50,000,000
Common stock, no par value	$ 0		$ 0
Preferred stock, shares authorized	10,000,000		10,000,000
Preferred stock, no par value	$ 0		$ 0
Preferred stock dividends	$ (18,000)	$ (18,000)
Preferred Stock, Dividends Per Share, Declared	$ 30	$ 30
Preferred Stock, Dividends, Per Share, Cash Paid	$ 30	$ 30
Common Stock [Member]
Earnings Per Share [Line Items]
Preferred stock dividends	$ 0	$ 0	$ 0	$ 0
Shares, issued	13,538,000	13,734,000	13,538,000	13,734,000	13,570,000	13,632,000	13,765,000	13,783,000
Repurchase of common stock, shares	(33,000)	(33,000)	(96,000)	(52,000)
Shares, outstanding	13,538,000	13,734,000	13,538,000	13,734,000	13,570,000	13,632,000	13,765,000	13,783,000
Series A preferred stock [Member]
Earnings Per Share [Line Items]
Preferred stock, shares issued	600,000		600,000			600,000
Preferred stock, shares outstanding	600,000		600,000			600,000
Common Stock [Member] | Common Stock [Member]
Earnings Per Share [Line Items]
Issuance of stock, shares	1,000	2,000	2,000	3,000

Shareholders' Equity (Schedule

Shareholders' Equity (Schedule Of Net Income (Loss) Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2022		Jun. 30, 2021	Jun. 30, 2022		Jun. 30, 2021
Earnings Per Share [Line Items]
Net income (loss) to common stockholders	$ (934,359)		$ 774,110	$ (987,202)		$ 1,347,804
Adjustment of redeemable noncontrolling interests	(7,498)		13,717	(44,438)		21,623
Adjusted net income (loss) to common shareholders	$ (941,857)		$ 787,827	$ (1,031,640)		$ 1,369,427
Basic common shares outstanding	13,612		13,793	13,632		13,806
Diluted shares outstanding	13,612		13,817	13,632		13,828
Basic net income (loss) per common share	$ (69.19)		$ 57.12	$ (75.68)		$ 99.19
Diluted net income (loss) per common share	$ (69.19)	[1]	$ 57.02	$ (75.68)	[1]	$ 99.03
Restricted Stock Units (RSUs) [Member]
Earnings Per Share [Line Items]
Dilutive potential common shares from restricted stock units and restricted stock	0	[1]	24	0	[1]	22
Potential incremental common shares attributable to share-based payment arrangements	31			29
[1]The impact of 31 thousand and 29 thousand shares from restricted stock units and restricted stock was excluded from the computation of diluted net loss per common share for the quarter and six months ended June 30, 2022, respectively, because the effect would have been anti-dilutive.

Commitments and Contingencies (

Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Mar. 31, 2022
Loss Contingencies [Line Items]
Cash funding used to purchase Markel CATCo Funds' interests in Markel CATCo Re		$ 45.1
Tail risk cover in Markel CATCo transaction	$ 142.7
Additional payments made, net of insurance in proceeds, to Markel CATCo Funds investors		$ 101.9

Accounting Changes and Error _2

Accounting Changes and Error Corrections (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Jan. 01, 2021
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Deferred policy acquisition costs	$ 954,521	$ 794,145
Retained earnings	$ 9,289,820	$ 10,446,763
Revision of Prior Period, Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Deferred policy acquisition costs			$ 28,200
Deferred tax liabilities			5,900
Retained earnings			$ 22,300

Uncategorized Items - mkl-20220

Label	Element	Value
Retained Earnings [Member]
Cumulative effect of change in accounting principle	mkl_CumulativeEffectOfChangeInAccountingPrinciple	$ 22,302,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	mkl_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance	8,217,484,000
AOCI Attributable to Parent [Member]
Cumulative effect of change in accounting principle	mkl_CumulativeEffectOfChangeInAccountingPrinciple	0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	mkl_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance	584,376,000
Total Equity [Member]
Cumulative effect of change in accounting principle	mkl_CumulativeEffectOfChangeInAccountingPrinciple	22,302,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	mkl_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance	12,836,983,000
Common Stock [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	mkl_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance	3,428,340,000
Preferred Stock [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	mkl_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance	591,891,000
Parent [Member]
Cumulative effect of change in accounting principle	mkl_CumulativeEffectOfChangeInAccountingPrinciple	22,302,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	mkl_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance	12,822,091,000
Noncontrolling Interest [Member]
Cumulative effect of change in accounting principle	mkl_CumulativeEffectOfChangeInAccountingPrinciple	0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	mkl_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance	14,892,000
Redeemable Noncontrolling Interests, Temporary Equity [Member]
Cumulative effect of change in accounting principle	mkl_CumulativeEffectOfChangeInAccountingPrinciple	0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	mkl_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance	$ 245,642,000