v3.26.3
Derivative Financial Instruments and Hedging (Effect of Derivative Instruments on Consolidated Statements of Income, Pre-tax, Hedges of net investment in foreign operations) (Detail) - Hedges of net investment in foreign operations - Derivatives designated as hedging instruments - JPY (¥)
¥ in Millions
 6 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Borrowings and bonds in foreign currencies    
Derivative Instruments, Gain (Loss) [Line Items]    
Gains (losses) recognized in other comprehensive income on derivative and others ¥ 1,210 ¥ 4,554
Foreign exchange contracts    
Derivative Instruments, Gain (Loss) [Line Items]    
Gains (losses) recognized in other comprehensive income on derivative and others (955) 356
Gains on sales of subsidiaries and equity method investments and liquidation losses, net | Borrowings and bonds in foreign currencies    
Derivative Instruments, Gain (Loss) [Line Items]    
Gains (losses) reclassified from other comprehensive income (loss) into income 0 0
Gains on sales of subsidiaries and equity method investments and liquidation losses, net | Foreign exchange contracts    
Derivative Instruments, Gain (Loss) [Line Items]    
Gains (losses) reclassified from other comprehensive income (loss) into income 0 9,890
Interest expense | Borrowings and bonds in foreign currencies    
Derivative Instruments, Gain (Loss) [Line Items]    
Gains (losses) reclassified from other comprehensive income (loss) into income 0 0
Interest expense | Foreign exchange contracts    
Derivative Instruments, Gain (Loss) [Line Items]    
Gains (losses) reclassified from other comprehensive income (loss) into income ¥ 2,082 ¥ 7,109