Income Taxes - Additional Information (Detail) - JPY (¥) ¥ in Millions |
12 Months Ended | ||
|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Statements [Line Items] | |||
| Temporary differences total | ¥ 5,237,041 | ¥ 5,667,006 | |
| Estimated amount of additional deferred tax liability if the undistributed earnings were to be distributed in the future | ¥ 328,627 | ¥ 245,292 | |
| Statutory tax rate | 30.90% | 30.90% | 30.90% |
| Adjustments related to deferred tax assets unrecognized tax benefits | ¥ 402,889 | ||
| Adjustments related to unrecognized tax benefits | ¥ 279,486 | ||
| Minimum corporate income tax rate under pillar two | 15.00% | ||