Affiliated companies and other equity-method investees - Additional information (Detail) - JPY (¥) ¥ in Millions |
Mar. 31, 2026 |
Mar. 31, 2025 |
|---|---|---|
| NRI [Member] | Equity Investments [Member] | ||
| Subsidiary or Equity Method Investee [Line Items] | ||
| Ownership percentage | 23.10% | 23.00% |
| NREH [Member] | ||
| Subsidiary or Equity Method Investee [Line Items] | ||
| Difference between the carrying amount of the equity method investment and the underlying equity in net assets | ¥ 21,810 | ¥ 31,576 |
| NREH [Member] | Equity Investments [Member] | ||
| Subsidiary or Equity Method Investee [Line Items] | ||
| Ownership percentage | 37.60% | 37.20% |