Write-Downs of Long-Lived Assets - Additional Information (Detail) - JPY (¥) ¥ in Millions |
6 Months Ended | |
|---|---|---|
Sep. 30, 2026 |
Sep. 30, 2025 |
|
| Property, Plant and Equipment [Abstract] | ||
| Write-downs of long-lived assets | ¥ 10,300 | ¥ 1,397 |
| Japan & APAC | ||
| Property, Plant and Equipment [Abstract] | ||
| Write-downs of long-lived assets | 263 | 1,053 |
| Infrastructure | ||
| Property, Plant and Equipment [Abstract] | ||
| Write-downs of long-lived assets | 419 | ¥ 344 |
| Corporate assets not attributable to any reportable segment | ||
| Property, Plant and Equipment [Abstract] | ||
| Write-downs of long-lived assets | ¥ 9,618 | |