v3.26.1
Unrealized Losses on Debt Investments (Detail) - USD ($)
$ in Millions
Jun. 30, 2026
Jun. 30, 2025
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value $ 25,145 $ 4,560
Less than 12 Months - Unrealized Losses (137) (65)
12 Months or Greater - Fair Value 23,232 38,176
12 Months or Greater - Unrealized Losses (1,137) (1,560)
Total Fair Value 48,377 42,736
Total Unrealized Losses (1,274) (1,625)
U.S. government and agency securities    
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value 19,100 2,569
Less than 12 Months - Unrealized Losses (100) (51)
12 Months or Greater - Fair Value 22,042 34,608
12 Months or Greater - Unrealized Losses (1,054) (1,411)
Total Fair Value 41,142 37,177
Total Unrealized Losses (1,154) (1,462)
Foreign government bonds    
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value 74 43
Less than 12 Months - Unrealized Losses (1) (2)
12 Months or Greater - Fair Value 30 106
12 Months or Greater - Unrealized Losses (6) (7)
Total Fair Value 104 149
Total Unrealized Losses (7) (9)
Mortgage- and asset-backed securities    
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value 905 841
Less than 12 Months - Unrealized Losses (5) (4)
12 Months or Greater - Fair Value 129 189
12 Months or Greater - Unrealized Losses (18) (23)
Total Fair Value 1,034 1,030
Total Unrealized Losses (23) (27)
Corporate notes and bonds    
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value 5,066 1,107
Less than 12 Months - Unrealized Losses (31) (8)
12 Months or Greater - Fair Value 909 3,105
12 Months or Greater - Unrealized Losses (40) (98)
Total Fair Value 5,975 4,212
Total Unrealized Losses (71) (106)
Municipal securities    
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value 0 0
Less than 12 Months - Unrealized Losses 0 0
12 Months or Greater - Fair Value 122 168
12 Months or Greater - Unrealized Losses (19) (21)
Total Fair Value 122 168
Total Unrealized Losses $ (19) $ (21)