v3.19.2
Unrealized Losses on Debt Investments (Detail) - USD ($)
$ in Millions
Jun. 30, 2019
Jun. 30, 2018
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value $ 2,678 $ 91,037
Less than 12 Months - Unrealized Losses (5) (1,124)
12 Months or Greater - Fair Value 39,989 4,869
12 Months or Greater - Unrealized Losses (117) (123)
Total Fair Value 42,667 95,906
Total Unrealized Losses (122) (1,247)
U.S. government and agency securities    
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value 1,491 82,352
Less than 12 Months - Unrealized Losses (1) (1,064)
12 Months or Greater - Fair Value 39,158 4,459
12 Months or Greater - Unrealized Losses (103) (103)
Total Fair Value 40,649 86,811
Total Unrealized Losses (104) (1,167)
Foreign government bonds    
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value 25 3,457
Less than 12 Months - Unrealized Losses 0 (7)
12 Months or Greater - Fair Value 77 13
12 Months or Greater - Unrealized Losses (8) (3)
Total Fair Value 102 3,470
Total Unrealized Losses (8) (10)
Mortgage- and asset-backed securities    
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value 664 2,072
Less than 12 Months - Unrealized Losses (1) (9)
12 Months or Greater - Fair Value 378 96
12 Months or Greater - Unrealized Losses (2) (4)
Total Fair Value 1,042 2,168
Total Unrealized Losses (3) (13)
Corporate notes and bonds    
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value 498 3,111
Less than 12 Months - Unrealized Losses (3) (43)
12 Months or Greater - Fair Value 376 301
12 Months or Greater - Unrealized Losses (4) (13)
Total Fair Value 874 3,412
Total Unrealized Losses $ (7) (56)
Municipal securities    
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value   45
Less than 12 Months - Unrealized Losses   (1)
12 Months or Greater - Fair Value   0
12 Months or Greater - Unrealized Losses   0
Total Fair Value   45
Total Unrealized Losses   $ (1)