Income Taxes - Additional Information (Detail) - JPY (¥) ¥ in Millions |
12 Months Ended | ||
|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Disclosure of income taxes [Line Items] | |||
| Statutory income tax rate | 30.20% | 30.20% | 30.20% |
| Deferred tax assets recognized by entities that have suffered a loss in either the preceding or current period | ¥ 103,123 | ¥ 637 | |
| Aggregate amounts of temporary differences relating to investments in subsidiaries and interests in joint ventures for which deferred tax liabilities are not recognized | ¥ 9,268,070 | ¥ 8,127,532 | |
| Japan [member] | |||
| Disclosure of income taxes [Line Items] | |||
| Statutory income tax rate | 30.20% | ||