Income and Expenses Relating to Life Insurance Operations - Reinsurance Benefits and Reinsurance Premiums Included in Life Insurance Premiums (Detail) - JPY (¥) ¥ in Millions |
12 Months Ended | ||
|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Policyholders Account In Life Insurance Business [Abstract] | |||
| Reinsurance benefits | ¥ 20,520 | ¥ 10,634 | ¥ 3,452 |
| Reinsurance premiums | ¥ (5,298) | ¥ (5,119) | ¥ (4,937) |