Other Operating Income - Schedule of Other Operating Income (Details) - JPY (¥) ¥ in Millions |
12 Months Ended | ||
|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Other Operating Income [Abstract] | |||
| Gain on expiration of contractual obligation | ¥ 1,752 | ¥ 1,216 | ¥ 1,258 |
| Received secondment and expense contributions | 330 | 276 | |
| Grants and contributions from non-governmental entities | 328 | ||
| Government grants | 574 | ||
| Other | 473 | 20 | 127 |
| Total | ¥ 2,883 | ¥ 1,512 | ¥ 1,959 |