v3.25.4
Significant accounting policies and practices - Narrative (Detail) - USD ($)
$ in Billions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Percentage of LIFO Inventory 30.00%  
Excess of current or replacement costs over costs determined under LIFO $ 2.5 $ 2.3
Other Assets [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Unamortized balances of deferred policy acquisition costs $ 4.8 $ 4.6
Maximum [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Trade receivables, insurance premiums receivables and other receivables collection term 1 year  
Maximum [Member] | Buildings and improvements [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Estimated useful life (in years) 50 years  
Maximum [Member] | Machinery and equipment [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Estimated useful life (in years) 30 years  
Maximum [Member] | Furniture, fixtures and other [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Estimated useful life (in years) 15 years  
Maximum [Member] | Track structure and other roadway [Member] | Railroad [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Estimated useful life (in years) 100 years  
Maximum [Member] | Locomotives, freight cars and other equipment [Member] | Railroad [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Estimated useful life (in years) 45 years  
Maximum [Member] | Utility generation, transmission and distribution systems [Member] | Utilities and Energy [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Estimated useful life (in years) 80 years  
Maximum [Member] | Interstate natural gas pipeline assets [Member] | Utilities and Energy [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Estimated useful life (in years) 80 years  
Maximum [Member] | Independent power plants and other assets [Member] | Utilities and Energy [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Estimated useful life (in years) 50 years  
Maximum [Member] | Equipment held for lease [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Estimated useful life (in years) 35 years  
Minimum [Member] | Buildings and improvements [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Estimated useful life (in years) 5 years  
Minimum [Member] | Machinery and equipment [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Estimated useful life (in years) 3 years  
Minimum [Member] | Furniture, fixtures and other [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Estimated useful life (in years) 4 years  
Minimum [Member] | Track structure and other roadway [Member] | Railroad [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Estimated useful life (in years) 10 years  
Minimum [Member] | Locomotives, freight cars and other equipment [Member] | Railroad [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Estimated useful life (in years) 6 years  
Minimum [Member] | Utility generation, transmission and distribution systems [Member] | Utilities and Energy [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Estimated useful life (in years) 5 years  
Minimum [Member] | Interstate natural gas pipeline assets [Member] | Utilities and Energy [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Estimated useful life (in years) 3 years  
Minimum [Member] | Independent power plants and other assets [Member] | Utilities and Energy [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Estimated useful life (in years) 2 years  
Minimum [Member] | Equipment held for lease [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Estimated useful life (in years) 3 years  
ASU 2023-09 [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Change in accounting principle, accounting standards update, adopted true  
Change in accounting principle, accounting standards update, adoption date Dec. 31, 2025