Revenue from services provided to customers - Schedule of disaggregation of brokerage commissions revenue (Detail) - JPY (¥) ¥ in Millions |
12 Months Ended | ||
|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Product Information [Line Items] | |||
| Commissions | ¥ 455,289 | ¥ 407,011 | ¥ 364,095 |
| Brokerage commissions [Member] | |||
| Product Information [Line Items] | |||
| Commissions | 295,192 | 264,512 | 242,687 |
| Commissions for distribution of investment trust [Member] | |||
| Product Information [Line Items] | |||
| Commissions | 66,345 | 66,108 | 56,241 |
| Other commissions [Member] | |||
| Product Information [Line Items] | |||
| Commissions | ¥ 93,752 | ¥ 76,391 | ¥ 65,167 |