v3.25.2
Income Taxes - Summary of Reconciliation of Statutory Tax Rate and Effective Income Tax Rate (Detail)
 12 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Mar. 31, 2023
Statements [Line Items]      
Statutory tax rate 30.90% 30.90% 30.90%
Increase (reduction) in taxes resulting from:      
Non-deductible expenses 0.80% 0.30% 0.80%
Tax-exempt income (0.60%) (0.20%) (0.40%)
Deferred tax liabilities on undistributed earnings of foreign subsidiaries 1.00% 0.60% 1.10%
Effects of investments accounted for using the equity method (2.80%) (3.40%) (5.40%)
Deferred tax liabilities on undistributed earnings of associates and joint ventures 1.90% 2.10% 3.10%
Change in unrecognized deferred tax assets 2.10% 0.40% 6.30%
Tax credits (4.20%) (2.10%) (3.50%)
The difference between the statutory tax rate in Japan and that of foreign subsidiaries (3.10%) (2.00%) (1.50%)
Unrecognized tax benefits adjustments (1.10%) 0.00% 0.40%
Revision to deferred tax assets and liabilities at the fiscal year-end due to changes in tax rates 0.40% 0.00%  
Other 0.00% 0.60% 0.30%
Average effective tax rate 25.30% 27.20% 32.00%