v3.26.1
Accumulated other comprehensive income (Detail) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance $ 717,419  
Ending Balance 747,910  
Unrealized investment gains (losses) [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance 235 $ 117
Other comprehensive income (105) 129
Ending Balance 130 246
Foreign currency translation [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance (5,537) (7,039)
Other comprehensive income (510) 1,521
Ending Balance (6,047) (5,518)
Long duration insurance contracts [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance 2,179 2,015
Other comprehensive income 201 118
Ending Balance 2,380 2,133
Defined benefit pension plans [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance 521 1,148
Other comprehensive income (13) (87)
Ending Balance 508 1,061
Other AOCI transactions [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance 154 175
Other comprehensive income (96) 8
Ending Balance 58 183
Accumulated other comprehensive income [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Beginning Balance (2,448) (3,584)
Other comprehensive income (523) 1,689
Ending Balance $ (2,971) $ (1,895)