Details of Company Organization - Additional Information (Detail) - JPY (¥) ¥ in Millions |
Mar. 31, 2025 |
Mar. 31, 2024 |
|---|---|---|
| Consolidated structured entities [Member] | ||
| Statement [Line Items] | ||
| Retail finance receivables | ¥ 7,280,835 | ¥ 6,257,786 |
| Secured debt | 7,486,241 | 6,371,509 |
| Unconsolidated structured entities [Member] | Other equity securities [Member] | ||
| Statement [Line Items] | ||
| Carrying value of investment trust securities | 167,038 | 92,875 |
| Unconsolidated structured entities [Member] | Debt securities [Member] | ||
| Statement [Line Items] | ||
| Carrying value of the special purpose entities | ¥ 2,517,967 | ¥ 1,911,621 |