v3.25.4
Fair value measurements - Financial assets and liabilities (Detail) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in fixed maturity securities $ 17,816 $ 15,364
Investments in equity securities 297,778 271,588
Insurance and Other [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in fixed maturity securities 17,816 15,364
Investments in equity securities 297,778 271,588
Other assets 24,413 24,994
Railroad, Utilities and Energy [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other assets 20,941 20,811
The Kraft Heinz Company [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity method investments, fair value 7,897 9,994
U.S. Treasury, U.S. government corporations and agencies [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in fixed maturity securities 3,849 4,459
Foreign governments [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in fixed maturity securities 12,542 9,362
Corporate and Other [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in fixed maturity securities 1,425 1,543
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in equity securities 288,232 261,910
Other assets 13 33
Other liabilities 13 15
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | The Kraft Heinz Company and Occidental Petroleum Corporation [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity method investments, fair value 18,791 23,047
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | U.S. Treasury, U.S. government corporations and agencies [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in fixed maturity securities 3,815 4,425
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Foreign governments [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in fixed maturity securities 12,411 9,199
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in equity securities 10 10
Loans and finance receivables 294 810
Other assets 119 158
Other liabilities 119 143
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Insurance and Other [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Notes payable and other borrowings 40,892 40,158
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Railroad, Utilities and Energy [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Notes payable and other borrowings 76,803 72,506
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | U.S. Treasury, U.S. government corporations and agencies [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in fixed maturity securities 34 34
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Foreign governments [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in fixed maturity securities 131 163
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Corporate and Other [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in fixed maturity securities 983 1,041
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in equity securities 9,536 9,668
Loans and finance receivables 30,238 26,769
Other assets 9 10
Other liabilities 56 76
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Insurance and Other [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Notes payable and other borrowings 32 23
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Corporate and Other [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in fixed maturity securities 442 502
Fair Value, Measurements, Recurring [Member] | Carrying Value [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in equity securities 297,778 271,588
Loans and finance receivables 29,836 27,798
Other assets 141 201
Other liabilities 188 234
Fair Value, Measurements, Recurring [Member] | Carrying Value [Member] | Insurance and Other [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Notes payable and other borrowings 45,763 44,885
Fair Value, Measurements, Recurring [Member] | Carrying Value [Member] | Railroad, Utilities and Energy [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Notes payable and other borrowings 83,318 79,877
Fair Value, Measurements, Recurring [Member] | Carrying Value [Member] | The Kraft Heinz Company and Occidental Petroleum Corporation [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity method investments, fair value 19,528 30,682
Fair Value, Measurements, Recurring [Member] | Carrying Value [Member] | U.S. Treasury, U.S. government corporations and agencies [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in fixed maturity securities 3,849 4,459
Fair Value, Measurements, Recurring [Member] | Carrying Value [Member] | Foreign governments [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in fixed maturity securities 12,542 9,362
Fair Value, Measurements, Recurring [Member] | Carrying Value [Member] | Corporate and Other [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in fixed maturity securities 1,425 1,543
Fair Value, Measurements, Recurring [Member] | Fair Value [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in equity securities 297,778 271,588
Loans and finance receivables 30,532 27,579
Other assets 141 201
Other liabilities 188 234
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | Insurance and Other [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Notes payable and other borrowings 40,924 40,181
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | Railroad, Utilities and Energy [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Notes payable and other borrowings 76,803 72,506
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | The Kraft Heinz Company and Occidental Petroleum Corporation [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity method investments, fair value 18,791 23,047
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | U.S. Treasury, U.S. government corporations and agencies [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in fixed maturity securities 3,849 4,459
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | Foreign governments [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in fixed maturity securities 12,542 9,362
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | Corporate and Other [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in fixed maturity securities $ 1,425 $ 1,543