v3.26.1
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
6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]    
Balance at June 30 $ 17,738 $ 17,865
Periodic Payment Annuity [Member]    
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]    
Balance at beginning of year 10,441 10,276
Balance at beginning of year at original discount rate 11,930 11,757
Effects of actual versus expected experience 3 (20)
Change in benefits, net (247) (240)
Interest accrual 281 277
Foreign currency effect (20) 136
Ending balance at original discount rate 11,947 11,910
Effects of changes in discount rate assumptions (1,642) (1,453)
Expected future policy benefits at June 30 10,305 10,457
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]    
Balance at June 30 10,305 10,457
Liabilities for future policy benefits at June 30, net of reinsurance recoverables 10,305 10,457
Life and Health [Member]    
Liability for Future Policy Benefit, Expected Future Policy Benefit [Roll Forward]    
Balance at beginning of year 48,124 43,784
Balance at beginning of year at original discount rate 61,247 55,170
Effects of cash flow assumption changes (283) (98)
Effects of actual versus expected experience 22 246
Change in benefits, net (721) (887)
Interest accrual 714 646
Foreign currency effect 332 1,489
Ending balance at original discount rate 61,311 56,566
Effects of changes in discount rate assumptions (14,571) (12,232)
Expected future policy benefits at June 30 46,740 44,334
Liability for Future Policy Benefit, Expected Net Premium [Roll Forward]    
Balance at beginning of year 43,584 39,294
Balance at beginning of year at original discount rate 55,359 49,500
Effects of cash flow assumption changes (201) (66)
Effect of actual versus expected experience (7) 204
Change in premiums, net (744) (884)
Interest accrual 646 579
Foreign currency effect 290 1,395
Ending balance at original discount rate 55,343 50,728
Effect of changes in discount rate assumptions (13,132) (10,898)
Expected future net premiums at June 30 42,211 39,830
Balance at June 30 4,529 4,504
Reinsurance recoverables (46) (51)
Liabilities for future policy benefits at June 30, net of reinsurance recoverables $ 4,483 $ 4,453