Basis of preparation - Additional Information (Detail) - JPY (¥) ¥ in Millions |
Mar. 31, 2026 |
Mar. 31, 2025 |
|---|---|---|
| Disclosure Of Basis Of Preparation [Line Items] | ||
| Current provisions | ¥ 431,191 | ¥ 413,352 |
| Non-current provisions | ¥ 498,463 | 301,103 |
| Reclassification From Other Liabilities To Provisions [Member] | ||
| Disclosure Of Basis Of Preparation [Line Items] | ||
| Current provisions | 413,352 | |
| Non-current provisions | ¥ 301,103 |