v3.25.2
General - Summary of Reclassifications to Amounts Previously Reported (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Costs and expenses:        
Interest expense $ 1,253 $ 1,230 $ 2,510 $ 2,546
Insurance and Other [Member]        
Revenues:        
Sales and service revenues 49,658 51,841 97,473 101,774
Interest, dividend and other investment income 6,002 5,284 11,634 9,622
Costs and expenses:        
Cost of sales and services 39,616 42,082 78,167 82,874
Selling, general and administrative expenses 7,931 6,033 15,612 11,574
Interest expense 318 336 658 742
Railroad, Utilities and Energy [Member]        
Revenues:        
Utility and energy operating revenues 5,118 5,103 10,612 10,336
Service revenues and other income 1,315 1,444 2,193 2,476
Costs and expenses:        
Utility and energy cost of sales and other expenses 4,156 4,290 8,247 8,393
Interest expense $ 935 894 $ 1,852 1,804
Previously Reported [Member] | Insurance and Other [Member]        
Revenues:        
Sales and service revenues   38,892   76,364
Interest, dividend and other investment income   5,249   9,554
Costs and expenses:        
Cost of sales and services   30,391   59,786
Selling, general and administrative expenses   5,195   9,968
Interest expense   330   646
Previously Reported [Member] | Railroad, Utilities and Energy [Member]        
Revenues:        
Utility and energy operating revenues   18,048   35,738
Service revenues and other income   1,483   2,552
Costs and expenses:        
Utility and energy cost of sales and other expenses   16,819   33,087
Interest expense   900   1,900
Reclassification [Member] | Insurance and Other [Member]        
Revenues:        
Sales and service revenues   12,949   25,410
Interest, dividend and other investment income   35   68
Costs and expenses:        
Cost of sales and services   11,691   23,088
Selling, general and administrative expenses   838   1,606
Interest expense   6   96
Reclassification [Member] | Railroad, Utilities and Energy [Member]        
Revenues:        
Utility and energy operating revenues   (12,945)   (25,402)
Service revenues and other income   (39)   (76)
Costs and expenses:        
Utility and energy cost of sales and other expenses   (12,529)   (24,694)
Interest expense   $ (6)   $ (96)