v3.26.1
Investments - Schedule of Available-For-Sale Securities in an Unrealized Loss Position (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Mar. 31, 2026
Dec. 31, 2025
Fair value:    
Less than 12 months $ 84,765 $ 8,238
12 months or longer 15,638 14,135
Total 100,403 22,373
Gross unrealized losses:    
Less than 12 months (572) (14)
12 months or longer (548) (484)
Total (1,120) (498)
Debt Securities, Available-for-Sale, Unrealized Gain (Loss) [Abstract]    
Gross unrealized gain included in accumulated other comprehensive gain/(loss) 237 626
U.S. government obligations    
Fair value:    
Less than 12 months 76,322 6,733
12 months or longer 12,635 10,464
Total 88,957 17,197
Gross unrealized losses:    
Less than 12 months (510) (12)
12 months or longer (282) (226)
Total (792) (238)
U.S. agency obligations    
Fair value:    
Less than 12 months 2,091 706
12 months or longer 0 0
Total 2,091 706
Gross unrealized losses:    
Less than 12 months (10) (1)
12 months or longer 0 0
Total (10) (1)
Non-U.S. government obligations    
Fair value:    
Less than 12 months 6,352 799
12 months or longer 3,003 3,671
Total 9,355 4,470
Gross unrealized losses:    
Less than 12 months (52) (1)
12 months or longer (266) (258)
Total $ (318) $ (259)