Research and Development - Summary of Research and Development Costs (Detail) - JPY (¥) ¥ in Millions |
12 Months Ended | ||
|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Material income and expense [abstract] | |||
| Research and development expenditures incurred during the reporting period | ¥ 1,174,848 | ¥ 1,210,620 | ¥ 976,366 |
| Amount capitalized | (198,806) | (287,098) | (207,519) |
| Amortization, impairment losses and losses on disposal of capitalized development costs | 564,604 | 175,960 | 154,780 |
| Total | ¥ 1,540,646 | ¥ 1,099,482 | ¥ 923,627 |