v3.26.1
Other Financial Assets - Summary of Other Financial Assets by Component (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Statement [Line Items]    
Current assets ¥ 3,982,445 ¥ 6,935,759
Non-current assets 11,135,799 9,882,841
Other financial assets 15,118,244 16,818,600
Financial assets measured at amortized cost [Member] | Time deposits [Member]    
Statement [Line Items]    
Other financial assets 988,027 2,264,841
Financial assets measured at amortized cost [Member] | Other [Member]    
Statement [Line Items]    
Other financial assets 752,598 837,954
Financial assets measured at fair value through profit or loss [Member] | Public and corporate bonds [Member]    
Statement [Line Items]    
Other financial assets 267,623 231,713
Financial assets measured at fair value through profit or loss [Member] | Stocks [Member]    
Statement [Line Items]    
Other financial assets 884,667 46,215
Financial assets measured at fair value through profit or loss [Member] | Investment trusts [Member]    
Statement [Line Items]    
Other financial assets 648,189 618,228
Financial assets measured at fair value through profit or loss [Member] | Derivatives [Member]    
Statement [Line Items]    
Other financial assets 479,447 483,378
Financial assets measured at fair value through other comprehensive income [Member] | Public and corporate bonds [Member]    
Statement [Line Items]    
Other financial assets 7,533,460 9,078,437
Financial assets measured at fair value through other comprehensive income [Member] | Stocks [Member]    
Statement [Line Items]    
Other financial assets 3,554,379 3,246,885
Financial assets measured at fair value through other comprehensive income [Member] | Other [Member]    
Statement [Line Items]    
Other financial assets ¥ 9,855 ¥ 10,947