Revenues from Contracts with Customers - Additional Information (Detail) - JPY (¥) ¥ in Millions |
6 Months Ended | |
|---|---|---|
Sep. 30, 2026 |
Sep. 30, 2025 |
|
| Revenue From Contract With Customers [Line Items] | ||
| Revenue included in contract liabilities | ¥ 25,887 | ¥ 25,325 |
| Revenue remaining performance obligation | ¥ 237,161 | |
| Automobile Services [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-04-01 | ||
| Revenue From Contract With Customers [Line Items] | ||
| Revenue remaining performance obligation expected timing of satisfaction period | 10 years | |
| Maximum | ||
| Revenue From Contract With Customers [Line Items] | ||
| Revenue remaining performance obligation expected timing of satisfaction, period | Remaining term for the obligations ranges up to 19 years. | |