Net Recognized Gains (Losses) on Debt Investments (Detail) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Mar. 31, 2023 |
Mar. 31, 2022 |
Mar. 31, 2023 |
Mar. 31, 2022 |
|
| 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 | $ 4 | $ 119 | $ 19 | $ 150 |
| Realized losses from sales of available-for-sale securities | (30) | (89) | (73) | (102) |
| Total | 105 | (76) | 103 | 595 |
| 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 | 0 | (45) | (13) | (53) |
| Total | $ (26) | $ (15) | $ (67) | $ (5) |