Related-Party Transactions - Additional Information (Detail) - JPY (¥) ¥ in Millions |
12 Months Ended | ||
|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Disclosure of transactions between related parties [line items] | |||
| Compensation of key management personnel, post-employment benefits | ¥ 0 | ¥ 0 | ¥ 0 |
| Compensation of key management personnel, other long-term benefits | 0 | 0 | 0 |
| Compensation of key management personnel, termination benefits | 0 | 0 | ¥ 0 |
| Associates [member] | |||
| Disclosure of transactions between related parties [line items] | |||
| Financial guarantees provided by related party | 313,115 | 482,991 | |
| Associates and joint ventures [Member] | |||
| Disclosure of transactions between related parties [line items] | |||
| Loan commitments to associates and joint ventures | ¥ 1,297,512 | ¥ 1,195,073 | |