XML 146 R121.htm IDEA: XBRL DOCUMENT v3.25.0.1
Markel Group (Parent Company Only) Financial Information (Schedule of Condensed Balance Sheets - Parenthetical) (Details) - USD ($)
$ in Thousands
Dec. 31, 2024
Dec. 31, 2023
Condensed Financial Statements, Captions [Line Items]    
Fixed maturities, amortized cost $ 16,457,723  
Equity securities cost 3,887,820 $ 3,497,071
Parent Company [Member]    
Condensed Financial Statements, Captions [Line Items]    
Fixed maturities, amortized cost 130,983 139,766
Equity securities cost $ 1,084,814 $ 1,089,332