v3.25.2
Income Taxes (Reconciliation of Effective Income Tax Rates) (Detail) - JPY (¥)
¥ in Millions
12 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Mar. 31, 2023
Reconciliation of effective income tax rate:      
Combined normal effective statutory tax rate 30.60% 30.60% 30.60%
Nondeductible expenses 0.40% 0.40% 1.10%
Impairment of goodwill 2.40% 0.00% 2.20%
Foreign tax credit and payments 0.20% 0.90% (6.70%)
Lower tax rates applicable to income of subsidiaries (2.50%) (1.50%) (4.10%)
Change in valuation allowance 0.30% (1.40%) (1.30%)
Taxation for gain on sale of shares in subsidiary 0.00% 0.00% 4.80%
Nontaxable dividends received (5.30%) (4.10%) (21.10%)
Undistributed earnings of subsidiaries 1.80% 0.90% 0.20%
Tax and interest expense for uncertainty in income taxes 1.70% 0.00% 0.00%
Tax penalty and tax refund (0.029) 0 0
Noncontrolling interest income 0.10% 0.60% 0.40%
Effect of changes in tax laws 1.20% 0.00% 0.90%
Expiration of loss carryforward 1.40% 0.10% 0.20%
Other—net 0.00% 0.20% 2.90%
Effective income tax rate 29.40% 26.70% 10.10%
Income tax expense ¥ 527,938 ¥ 500,657 ¥ 46,751
Increase in tax expense previously not recognized   22,250  
Increase in tax expense previously not recognized, percentage     4.80%
Income Tax Expense (Benefit) (527,938) ¥ (500,657) ¥ (46,751)
CALIFORNIA      
Reconciliation of effective income tax rate:      
Income tax expense (52,129)    
Income Tax Expense (Benefit) ¥ 52,129