v3.26.1
Accumulated other comprehensive income (Detail) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance $ 717,419  
Ending Balance 727,181  
Unrealized investment gains (losses) [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance 235 $ 117
Other comprehensive income (58) 30
Ending Balance 177 147
Foreign currency translation [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance (5,537) (7,039)
Other comprehensive income (260) 474
Ending Balance (5,797) (6,565)
Long duration insurance contracts [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance 2,179 2,015
Other comprehensive income 286 28
Ending Balance 2,465 2,043
Defined benefit pension plans [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance 521 1,148
Other comprehensive income 3 (38)
Ending Balance 524 1,110
Other AOCI transactions [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance 154 175
Other comprehensive income (34) 6
Ending Balance 120 181
Accumulated other comprehensive income [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance (2,448) (3,584)
Other comprehensive income (63) 500
Ending Balance $ (2,511) $ (3,084)