Net Recognized Gains (Losses) on Debt Investments (Detail) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Mar. 31, 2026 |
Mar. 31, 2025 |
|
| Schedule Of Gain Loss On Investments Including Marketable Securities And Investments Held At Cost Income Statement Reported Amounts Summary [Line Items] | ||||
| Realized gains from sales of available-for-sale securities | $ 54 | $ 8 | $ 89 | $ 25 |
| Realized losses from sales of available-for-sale securities | (18) | (17) | (37) | (51) |
| Total | 1,652 | 111 | 1,419 | (286) |
| Debt Securities | ||||
| Schedule Of Gain Loss On Investments Including Marketable Securities And Investments Held At Cost Income Statement Reported Amounts Summary [Line Items] | ||||
| Impairments and allowance for credit losses | (6) | 3 | (23) | 1 |
| Total | $ 30 | $ (6) | $ 29 | $ (25) |