v3.26.1
Income Taxes - Additional information (Detail) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Dec. 01, 2025
Income Taxes [Line Items]        
Income tax benefit recognized from operating losses ¥ 5,298 ¥ 6,086 ¥ 1,901  
Net deferred tax assets reported within Other assets-Other [1] 41,778 25,224    
Net deferred tax liabilities reported within Other liabilities [1] 146,706 113,820    
Operating loss carryforwards 2,308,076      
Decrease in unrecognized tax benefits is reasonably possible 25,658 17,561 10,057  
Deferred tax assets       ¥ 10,479
Deferred tax liabilities       11,820
Additional Deferred Tax Asset Recognized 247,664 212,859    
Additional Deferred Tax Liability Recognized 104,928 88,596    
Valuation allowance release 17,409 [2] ¥ (24,651) [3] ¥ 80,600 [4]  
Unrecognized Tax Benefits, Interest on Income Taxes Expense 1,493      
Macquarie Management Holdings Inc [Member]        
Income Taxes [Line Items]        
Deferred tax assets       11,389
Deferred tax liabilities       ¥ 26,001
Additional Deferred Tax Asset Recognized 929      
Additional Deferred Tax Liability Recognized 14,476      
Valuation allowance release (12,769)      
Indefinitely [Member]        
Income Taxes [Line Items]        
Operating loss carryforwards 1,539,348      
Initial term [Member]        
Income Taxes [Line Items]        
Operating loss carryforwards ¥ 729,875      
Expiration year Mar. 31, 2036      
Next term [Member]        
Income Taxes [Line Items]        
Operating loss carryforwards ¥ 38,853      
Company and domestic subsidiaries [Member] | Domestic [Member]        
Income Taxes [Line Items]        
Operating loss carryforwards 307,780      
Subsidiaries [Member] | United Kingdom [Member]        
Income Taxes [Line Items]        
Operating loss carryforwards 852,730      
Subsidiaries [Member] | United States [Member]        
Income Taxes [Line Items]        
Operating loss carryforwards 665,526      
Subsidiaries [Member] | Hong Kong [Member]        
Income Taxes [Line Items]        
Operating loss carryforwards 380,924      
Subsidiaries [Member] | Foreign Tax Authority [Member]        
Income Taxes [Line Items]        
Operating loss carryforwards ¥ 101,116      
[1] Net deferred tax assets are deferred tax assets offset by deferred tax liabilities which relate to the same tax-paying component within a particular tax jurisdiction. Net deferred tax liabilities are deferred tax liabilities offset by deferred tax assets which relate to the same tax-paying component within a particular tax jurisdiction. See Note 17 “Income taxes” for further information.
[2] Primarily includes an increase of ¥12,691 million of valuation allowances on deferred tax assets primarily related to valuation of financial instruments of certain foreign subsidiaries. While valuation allowances on deferred tax assets of foreign subsidiaries related to operating loss carryforwards had increases due to foreign exchange, valuation allowances of certain foreign subsidiaries had decreases in operating loss carryforwards due to utilization by improved profitability, resulting in an immaterial net change during the year. In addition, there was an increase of ¥4,718 million of valuation allowances on deferred tax assets related to Japanese subsidiaries and the Company primarily due to an increase of valuation allowances of Investments in subsidiaries and affiliates. In total, ¥17,409 million of allowances increased.
[3] Primarily includes a decrease of ¥21,610 million of valuation allowances on deferred tax assets of certain foreign subsidiaries primarily due to a decrease in operating loss carryforwards, and a reduction of ¥3,041 million of valuation allowances on deferred tax assets related to Japanese subsidiaries and the Company primarily due to a utilization of loss carryforwards. In total, ¥24,651 million of allowances decreased.
[4] Primarily includes an increase of ¥83,838 million of valuation allowances on deferred tax assets of certain foreign subsidiaries primarily due to an increase in operating loss carryforwards, and a reduction of ¥3,238 million of valuation allowances on deferred tax assets related to Japanese subsidiaries and the Company primarily due to a utilization of loss carryforwards. In total, ¥80,600 million of allowances increased.