Net Recognized Gains (Losses) on Debt Investments (Detail) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Dec. 31, 2022 |
Dec. 31, 2021 |
Dec. 31, 2022 |
Dec. 31, 2021 |
|
| 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 | $ 27 | $ 12 | $ 30 | $ 31 |
| Realized losses from sales of available-for-sale securities | (23) | (6) | (43) | (13) |
| Total | (15) | 300 | (2) | 671 |
| 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 | 5 | (5) | (13) | (8) |
| Total | $ 9 | $ 1 | $ (26) | $ 10 |