Details of Company Organization - Additional Information (Detail) - JPY (¥) ¥ in Millions |
Mar. 31, 2026 |
Mar. 31, 2025 |
|---|---|---|
| Consolidated structured entities [Member] | ||
| Statement [Line Items] | ||
| Retail finance receivables | ¥ 8,267,069 | ¥ 7,280,835 |
| Secured debt | 8,664,183 | 7,486,241 |
| Unconsolidated structured entities [Member] | Other equity securities [Member] | ||
| Statement [Line Items] | ||
| Carrying value of investment trust securities | 113,204 | 167,038 |
| Unconsolidated structured entities [Member] | Debt securities [Member] | ||
| Statement [Line Items] | ||
| Carrying value of the special purpose entities | ¥ 1,049,995 | ¥ 2,517,967 |