v3.25.2
Investment gains (losses) - Narrative (Detail) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Gain (Loss) on Securities [Line Items]        
Sales of equity securities     $ 11,592 $ 97,123
Taxable gains (losses) on sales of equity securities $ 5,300 $ 59,600 $ 8,400 $ 73,700