v3.25.4
Long-duration insurance contracts - Summary of changes in discounted present values of expected future policy benefits and expected future net premiums (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]    
Balance at December 31 $ 17,890 $ 17,616
Periodic Payment Annuity [Member]    
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]    
Balance at beginning of year 10,276 11,212
Balance at beginning of year at original discount rate 11,757 11,681
Effects of cash flow assumption changes 21  
Effects of actual versus expected experience (14) 3
Change in benefits, net (499) (478)
Interest accrual 557 550
Foreign currency effect 108 1
Ending balance at original discount rate 11,930 11,757
Effects of changes in discount rate assumptions (1,489) (1,481)
Expected future policy benefits at December 31 10,441 10,276
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]    
Balance at December 31 10,441 10,276
Liability for future policy benefits at December 31, net of reinsurance recoverables 10,441 10,276
Life and Health [Member]    
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]    
Balance at beginning of year 43,784 52,665
Balance at beginning of year at original discount rate 55,170 65,871
Effects of cash flow assumption changes 80 (348)
Effects of actual versus expected experience 1,161 (12,711)
Change in benefits, net 2,138 1,991
Interest accrual 1,362 1,234
Foreign currency effect 1,336 (867)
Ending balance at original discount rate 61,247 55,170
Effects of changes in discount rate assumptions (13,123) (11,386)
Expected future policy benefits at December 31 48,124 43,784
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]    
Balance at beginning of year 39,294 46,916
Balance at beginning of year at original discount rate 49,500 58,731
Effects of cash flow assumption changes 156 (416)
Effects of actual versus expected experience 1,112 (11,104)
Change in premiums, net 2,135 1,984
Interest accrual 1,227 1,099
Foreign currency effect 1,229 (794)
Ending balance at original discount rate 55,359 49,500
Effects of changes in discount rate assumptions (11,775) (10,206)
Expected future net premiums at December 31 43,584 39,294
Balance at December 31 4,540 4,490
Reinsurance recoverables (49) (46)
Liability for future policy benefits at December 31, net of reinsurance recoverables $ 4,491 $ 4,444