Stockholders' equity - Summary of Dividends (Detail) - JPY (¥) ¥ / shares in Units, ¥ in Millions |
12 Months Ended | |||||||
|---|---|---|---|---|---|---|---|---|
Mar. 31, 2025 |
Mar. 31, 2024 |
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| Disclosure Of Dividends [Line Items] | ||||||||
| Type of shares | Common stock | Common stock | ||||||
| Total amount of dividends | ¥ 60,250 | ¥ 54,965 | ||||||
| Source of dividends | Retained earnings | Retained earnings | ||||||
| Dividends per share | ¥ 10 | [1] | ¥ 45 | [2] | ||||
| Record date | Mar. 31, 2025 | Mar. 31, 2024 | ||||||
| Effective date | Jun. 02, 2025 | Jun. 10, 2024 | ||||||
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