Short-Term and Long-Term Debt (Composition of Short-Term Debt and Weighted Average Contract Interest Rate on Short-Term Debt) (Detail) - JPY (¥) ¥ in Millions |
Mar. 31, 2026 |
Mar. 31, 2025 |
|---|---|---|
| Short-term Debt [Line Items] | ||
| Short-term debt | ¥ 572,235 | ¥ 549,680 |
| Weighted average rate | 3.10% | 3.40% |
| Secured borrowings on securities lending transactions [Member] | ||
| Short-term Debt [Line Items] | ||
| Short-term debt | ¥ 107,095 | ¥ 80,626 |
| Weighted average rate | 2.60% | 2.30% |
| Japan | Bank Borrowings | ||
| Short-term Debt [Line Items] | ||
| Short-term debt | ¥ 131,655 | ¥ 181,835 |
| Weighted average rate | 1.30% | 0.70% |
| Overseas | Bank Borrowings | ||
| Short-term Debt [Line Items] | ||
| Short-term debt | ¥ 329,499 | ¥ 279,631 |
| Weighted average rate | 3.90% | 5.50% |
| Overseas | Commercial Paper | ||
| Short-term Debt [Line Items] | ||
| Short-term debt | ¥ 3,986 | ¥ 7,588 |
| Weighted average rate | 2.00% | 2.90% |