Employee benefits - Summary of Defined Contribution Expenses (Detail) - JPY (¥) ¥ in Millions |
12 Months Ended | ||
|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Japanese Plans [Member] | |||
| Disclosure of Detailed Information About Defined Contribution Plans Explanatory [Line Items] | |||
| Total defined contribution expenses | ¥ 11,125 | ¥ 11,849 | ¥ 11,662 |
| Foreign Plans [Member] | |||
| Disclosure of Detailed Information About Defined Contribution Plans Explanatory [Line Items] | |||
| Total defined contribution expenses | ¥ 19,112 | ¥ 17,209 | ¥ 16,137 |