Financial Risks - Summary of Sensitivity Analysis of Fair Value Measurement To Changes in Unobservable Inputs, Assets (Detail) - JPY (¥) ¥ in Millions |
12 Months Ended | |
|---|---|---|
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Disclosure of sensitivity analysis of fair value measurement to changes in unobservable inputs, assets [line items] | ||
| Impact on income before income taxes | ¥ (104,706) | ¥ (49,799) |
| Impact on other comprehensive income, before tax effect | ¥ (235,959) | ¥ (221,420) |