v3.26.1
Income Taxes (Reconciliations of Differences between Tax Provision Computed at Statutory Rate and Consolidated Provision for Income Taxes) (Detail) - JPY (¥)
¥ in Millions
12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Effective Income Tax Rate Reconciliation [Line Items]      
Income before income taxes ¥ 691,431 ¥ 480,463 ¥ 469,975
Tax provision computed at the national statutory income tax rate   151,346 148,042
Increases (reductions) in taxes due to:      
Effect of the tax law and rate changes   2,218 (1,295)
Change in valuation allowance   1,973 5,441
Nondeductible expenses   5,813 4,762
Nontaxable income   (5,893) (3,574)
Effect of investor taxes on earnings of subsidiaries   3,494 7,674
Effect of lower tax rates on certain subsidiaries   (22,271) (17,627)
Effect of sale or liquidation of subsidiaries   (8,423) (14,995)
Other, net   571 2,960
Worldwide changes in unrecognized tax benefits 323    
Provision for income taxes ¥ 233,103 ¥ 128,828 ¥ 131,388
Effective Income Tax Rate Reconciliation, Percent [Abstract]      
Tax provision computed at the national statutory income tax rate, Percent 31.50% 31.50% 31.50%
Worldwide changes in unrecognized tax benefits, Percent 0.10%    
Provision for income taxes, Percent 33.70%    
Japan Local tax [Member]      
Increases (reductions) in taxes due to:      
Local tax ¥ 34,215    
Effective Income Tax Rate Reconciliation, Percent [Abstract]      
Japan local tax, net of national tax effect, Percent 4.90%    
Japan national tax [Member]      
Effective Income Tax Rate Reconciliation [Line Items]      
Tax provision computed at the national statutory income tax rate ¥ 177,006    
Increases (reductions) in taxes due to:      
Nontaxable and nondeductible items (223)    
Foreign tax credit (9,769)    
Other (1,539)    
Effect of the tax law and rate changes 1,012    
Change in valuation allowance 2,375    
Cross-border tax laws 10,975    
Other, net ¥ 6,715    
Effective Income Tax Rate Reconciliation, Percent [Abstract]      
Tax provision computed at the national statutory income tax rate, Percent 25.60%    
Nontaxable and nondeductible items, Percent 0.00%    
Foreign tax credit, Percent (1.40%)    
Other, Percent (0.20%)    
Effect of the tax law and rate changes, Percent 0.10%    
Change in valuation allowance, Percent 0.30%    
Cross-border tax laws, Percent 1.60%    
Other, net, Percent 1.00%    
Foreign tax effects [Member] | Americas [Member]      
Increases (reductions) in taxes due to:      
Effect of lower tax rates on certain subsidiaries ¥ 9,030    
Effective Income Tax Rate Reconciliation, Percent [Abstract]      
Effect of lower tax rates on certain subsidiaries, Percent 1.30%    
Foreign tax effects [Member] | India      
Increases (reductions) in taxes due to:      
Direct foreign withholding tax ¥ 10,367    
Other, net ¥ 138    
Effective Income Tax Rate Reconciliation, Percent [Abstract]      
Direct foreign withholding tax, Percent 1.50%    
Other, Percent 0.00%    
Foreign tax effects [Member] | Other foreign jurisdictions [Member]      
Increases (reductions) in taxes due to:      
Effect of lower tax rates on certain subsidiaries ¥ (7,522)    
Effective Income Tax Rate Reconciliation, Percent [Abstract]      
Effect of lower tax rates on certain subsidiaries, Percent (1.10%)