Assets Pledged and Received as Collateral - Additional information (Detail) - JPY (¥) ¥ in Millions |
Mar. 31, 2026 |
Mar. 31, 2025 |
|---|---|---|
| Disclosure of detailed information about financial instruments [abstract] | ||
| Loaned securities for which the borrowers have the right to sell or repledge | ¥ 14,478,581 | ¥ 17,619,448 |
| Fair value of securities and bills accepted as collateral | 32,574,165 | 27,668,614 |
| Fair value of securities sold or repledged to others | ¥ 17,437,371 | ¥ 13,400,920 |