Employee benefits - Summary of Weighted Average Duration of Defined Benefit Obligations (Detail) |
12 Months Ended | |
|---|---|---|
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Japanese Defined Benefit Plans [Member] | ||
| Disclosure of defined benefit plans [line items] | ||
| Weighted average duration of defined benefit obligations | 10 years 7 months 6 days | 10 years 10 months 24 days |
| Foreign Defined Benefit Plan [Member] | ||
| Disclosure of defined benefit plans [line items] | ||
| Weighted average duration of defined benefit obligations | 11 years 10 months 24 days | 12 years 6 months |