v3.25.4
Common stock - Narrative (Detail)
 12 Months Ended
Dec. 31, 2025
USD ($)
Vote
shares
Dec. 31, 2024
shares
Dec. 31, 2023
shares
Dec. 31, 2022
shares
Dec. 31, 2021
Class of Stock [Line Items]          
Preferred Stock, shares authorized 1,000,000        
Preferred Stock, shares issued 0        
Economic equivalent of Class B share to Class A share 0.0667%       0.0667%
Common Stock Repurchase Program [Member]          
Class of Stock [Line Items]          
Shares repurchase, authorization description Berkshire’s common stock repurchase program currently permits Berkshire to repurchase shares any time that Berkshire’s Chief Executive Officer, after consultation with the Chairman of the Board, believes that the repurchase price is below Berkshire’s intrinsic value, conservatively determined.        
Minimum cash, cash equivalents and U.S. Treasury Bill threshold after repurchase of common stock shares, amount | $ $ 30,000,000,000        
Class A [Member]          
Class of Stock [Line Items]          
Number of votes entitled per share, number | Vote 1        
Shares outstanding 515,835 547,562 567,775 591,564  
Class B [Member]          
Class of Stock [Line Items]          
Number of votes entitled per share, number | Vote 0.0001        
Number of shares of Class B stock obtainable from converting one Class A share 1,500        
Shares outstanding 1,383,582,639 1,335,992,139 1,310,561,508 1,302,254,076  
Equivalent Class A [Member]          
Class of Stock [Line Items]          
Shares outstanding 1,438,223 1,438,223