Net Investment Income - Summary of Net Investment Income (Detail) - JPY (¥) ¥ in Millions |
12 Months Ended | ||
|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Disclosure of detailed information about financial instruments [line items] | |||
| Dividend income | ¥ 128,021 | ¥ 124,326 | ¥ 115,667 |
| Total net investment income | 20,686 | 78,969 | 29,844 |
| Debt instruments [member] | |||
| Disclosure of detailed information about financial instruments [line items] | |||
| Net loss from disposal of debt instruments | ¥ (107,335) | ¥ (45,357) | ¥ (85,823) |