Credit Quality of Financial Assets and the Allowance for Credit Losses - Summary of Disclosure In Tabular Form Of Allowances For Credit Losses And Provision For Credit Losses (Parenthetical) (Detail) - JPY (¥) ¥ in Millions |
Sep. 30, 2026 |
Mar. 31, 2026 |
|---|---|---|
| Disclosure in Tabular Form of Allowances for Credit Losses and Provision for Credit Losses [Abstract] | ||
| Allowance for credit losses on off balance sheet exposures | ¥ 17,175 | ¥ 17,611 |
| Allowance for credit loss on available for sale debt securities | ¥ 3,354 | ¥ 3,505 |