Employee benefits - Summary of Weighted-Average Actuarial Assumptions Used to Determine the Present Value of Defined Benefit Obligations (Detail) |
Mar. 31, 2025 |
Mar. 31, 2024 |
|---|---|---|
| Japanese Defined Benefit Plans [Member] | ||
| Disclosure of significant weighted average actuarial assumptions used to determine the present value of defined benefit obligations explanatory [Line Items] | ||
| Actuarial assumption of discount rates | 2.10% | 1.40% |
| Foreign Defined Benefit Plan [Member] | ||
| Disclosure of significant weighted average actuarial assumptions used to determine the present value of defined benefit obligations explanatory [Line Items] | ||
| Actuarial assumption of discount rates | 4.10% | 4.10% |