Guarantee Deposits - Schedule of Guarantee Deposits (Details) - JPY (¥) ¥ in Millions |
Mar. 31, 2026 |
Mar. 31, 2025 |
|---|---|---|
| Guarantee Deposits [Abstract] | ||
| Guarantee deposits under Payment Services Act | ¥ 49,734 | ¥ 219,466 |
| Payment, Subtotal | 49,734 | 219,466 |
| Other | 24,405 | 24,763 |
| Financial service, Subtotal | 24,405 | 24,763 |
| Total | ¥ 74,139 | ¥ 244,229 |