v3.26.1
Property, plant and equipment (Detail) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Insurance and Other [Member]    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross $ 70,802 $ 62,979
Property, plant and equipment, accumulated depreciation (31,760) (31,094)
Total property, plant and equipment, net 39,042 31,885
Insurance and Other [Member] | Land, buildings and improvements [Member]    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 23,451 22,034
Insurance and Other [Member] | Machinery and equipment [Member]    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 39,419 34,733
Insurance and Other [Member] | Furniture, fixtures and other [Member]    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 7,932 6,212
Railroad [Member]    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 95,241 94,699
Property, plant and equipment, accumulated depreciation (22,779) (22,327)
Total property, plant and equipment, net 72,462 72,372
Railroad [Member] | Land, track structure and other roadway [Member]    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 77,044 76,764
Railroad [Member] | Locomotives, freight cars and other equipment [Member]    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 15,982 15,772
Railroad [Member] | Construction in progress [Member]    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 2,215 2,163
Utilities and Energy [Member]    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 156,739 157,370
Property, plant and equipment, accumulated depreciation (45,173) (45,002)
Total property, plant and equipment, net 111,566 112,368
Utilities and Energy [Member] | Utility generation, transmission and distribution systems [Member]    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 108,515 109,815
Utilities and Energy [Member] | Interstate natural gas pipeline assets [Member]    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 21,495 21,334
Utilities and Energy [Member] | Independent power plants and other [Member]    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 15,636 15,630
Utilities and Energy [Member] | Construction in progress [Member]    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 11,093 10,591
Railroad, Utilities and Energy [Member]    
Property, Plant and Equipment [Line Items]    
Total property, plant and equipment, net $ 184,028 $ 184,740