v3.26.1
Fair Value - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets ¥ 1,508,493 ¥ 1,081,937  
Other financial liabilities 581,096 578,300  
Debt securities [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 41,564 84,018  
Measured at fair value on a recurring basis [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 1,040,414 736,745  
Other financial liabilities 122,477 171,630  
Measured at fair value on a recurring basis [member] | Derivatives [member] | Cash flow hedges [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 64,541    
Measured at fair value on a recurring basis [member] | Financial liabilities measured at fair value through profit or loss [member] | Foreign exchange instruments [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial liabilities 51,870 70,495  
Measured at fair value on a recurring basis [member] | Financial liabilities measured at fair value through profit or loss [member] | Interest rate instruments [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial liabilities 70,607 101,049  
Measured at fair value on a recurring basis [member] | Financial liabilities measured at fair value through profit or loss [member] | Other [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial liabilities 86  
Measured at fair value on a recurring basis [member] | Financial liabilities measured at fair value through profit or loss [member] | Derivatives [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial liabilities 122,477 171,630  
Measured at fair value on a recurring basis [member] | Financial assets measured at fair value through profit or loss [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 127,834    
Measured at fair value on a recurring basis [member] | Financial assets measured at fair value through profit or loss [member] | Foreign exchange instruments [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 133,616 71,516  
Measured at fair value on a recurring basis [member] | Financial assets measured at fair value through profit or loss [member] | Interest rate instruments [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 36,465 50,612  
Measured at fair value on a recurring basis [member] | Financial assets measured at fair value through profit or loss [member] | Other [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 12,163 10,949  
Measured at fair value on a recurring basis [member] | Financial assets measured at fair value through profit or loss [member] | Derivatives [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 182,244 133,077  
Measured at fair value on a recurring basis [member] | Financial assets measured at fair value through profit or loss [member] | Debt securities [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets   134,204  
Measured at fair value on a recurring basis [member] | Financial assets measured at fair value through other comprehensive income [member] | Debt securities [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 31,920 34,872  
Measured at fair value on a recurring basis [member] | Financial assets measured at fair value through other comprehensive income [member] | Equity securities [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 633,875 434,592  
Measured at fair value on a recurring basis [member] | Level 1 [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 597,221 440,479  
Other financial liabilities  
Measured at fair value on a recurring basis [member] | Level 1 [member] | Derivatives [member] | Cash flow hedges [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets    
Measured at fair value on a recurring basis [member] | Level 1 [member] | Financial liabilities measured at fair value through profit or loss [member] | Foreign exchange instruments [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial liabilities  
Measured at fair value on a recurring basis [member] | Level 1 [member] | Financial liabilities measured at fair value through profit or loss [member] | Interest rate instruments [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial liabilities  
Measured at fair value on a recurring basis [member] | Level 1 [member] | Financial liabilities measured at fair value through profit or loss [member] | Other [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial liabilities  
Measured at fair value on a recurring basis [member] | Level 1 [member] | Financial liabilities measured at fair value through profit or loss [member] | Derivatives [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial liabilities  
Measured at fair value on a recurring basis [member] | Level 1 [member] | Financial assets measured at fair value through profit or loss [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 32,936    
Measured at fair value on a recurring basis [member] | Level 1 [member] | Financial assets measured at fair value through profit or loss [member] | Foreign exchange instruments [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets  
Measured at fair value on a recurring basis [member] | Level 1 [member] | Financial assets measured at fair value through profit or loss [member] | Interest rate instruments [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets  
Measured at fair value on a recurring basis [member] | Level 1 [member] | Financial assets measured at fair value through profit or loss [member] | Other [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets  
Measured at fair value on a recurring basis [member] | Level 1 [member] | Financial assets measured at fair value through profit or loss [member] | Derivatives [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets  
Measured at fair value on a recurring basis [member] | Level 1 [member] | Financial assets measured at fair value through profit or loss [member] | Debt securities [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets   56,070  
Measured at fair value on a recurring basis [member] | Level 1 [member] | Financial assets measured at fair value through other comprehensive income [member] | Debt securities [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets  
Measured at fair value on a recurring basis [member] | Level 1 [member] | Financial assets measured at fair value through other comprehensive income [member] | Equity securities [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 564,285 384,409  
Measured at fair value on a recurring basis [member] | Level 2 [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 356,853 230,648  
Other financial liabilities 122,477 171,630  
Measured at fair value on a recurring basis [member] | Level 2 [member] | Derivatives [member] | Cash flow hedges [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 64,541    
Measured at fair value on a recurring basis [member] | Level 2 [member] | Financial liabilities measured at fair value through profit or loss [member] | Foreign exchange instruments [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial liabilities 51,870 70,495  
Measured at fair value on a recurring basis [member] | Level 2 [member] | Financial liabilities measured at fair value through profit or loss [member] | Interest rate instruments [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial liabilities 70,607 101,049  
Measured at fair value on a recurring basis [member] | Level 2 [member] | Financial liabilities measured at fair value through profit or loss [member] | Other [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial liabilities 86  
Measured at fair value on a recurring basis [member] | Level 2 [member] | Financial liabilities measured at fair value through profit or loss [member] | Derivatives [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial liabilities 122,477 171,630  
Measured at fair value on a recurring basis [member] | Level 2 [member] | Financial assets measured at fair value through profit or loss [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 90,102    
Measured at fair value on a recurring basis [member] | Level 2 [member] | Financial assets measured at fair value through profit or loss [member] | Foreign exchange instruments [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 133,616 71,516  
Measured at fair value on a recurring basis [member] | Level 2 [member] | Financial assets measured at fair value through profit or loss [member] | Interest rate instruments [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 36,465 50,612  
Measured at fair value on a recurring basis [member] | Level 2 [member] | Financial assets measured at fair value through profit or loss [member] | Other [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 209    
Measured at fair value on a recurring basis [member] | Level 2 [member] | Financial assets measured at fair value through profit or loss [member] | Derivatives [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 170,290 122,128  
Measured at fair value on a recurring basis [member] | Level 2 [member] | Financial assets measured at fair value through profit or loss [member] | Debt securities [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets   73,648  
Measured at fair value on a recurring basis [member] | Level 2 [member] | Financial assets measured at fair value through other comprehensive income [member] | Debt securities [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 31,920 34,872  
Measured at fair value on a recurring basis [member] | Level 2 [member] | Financial assets measured at fair value through other comprehensive income [member] | Equity securities [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 0  
Measured at fair value on a recurring basis [member] | Level 3 [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 86,340 65,618  
Other financial liabilities  
Measured at fair value on a recurring basis [member] | Level 3 [member] | Derivatives [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 11,954 10,949 ¥ 5,806
Measured at fair value on a recurring basis [member] | Level 3 [member] | Derivatives [member] | Cash flow hedges [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets    
Measured at fair value on a recurring basis [member] | Level 3 [member] | Debt securities [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 4,796 4,486 4,542
Measured at fair value on a recurring basis [member] | Level 3 [member] | Equity securities [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 69,590 50,183 ¥ 115,214
Measured at fair value on a recurring basis [member] | Level 3 [member] | Financial liabilities measured at fair value through profit or loss [member] | Foreign exchange instruments [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial liabilities  
Measured at fair value on a recurring basis [member] | Level 3 [member] | Financial liabilities measured at fair value through profit or loss [member] | Interest rate instruments [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial liabilities  
Measured at fair value on a recurring basis [member] | Level 3 [member] | Financial liabilities measured at fair value through profit or loss [member] | Other [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial liabilities  
Measured at fair value on a recurring basis [member] | Level 3 [member] | Financial liabilities measured at fair value through profit or loss [member] | Derivatives [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial liabilities  
Measured at fair value on a recurring basis [member] | Level 3 [member] | Financial assets measured at fair value through profit or loss [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 4,796    
Measured at fair value on a recurring basis [member] | Level 3 [member] | Financial assets measured at fair value through profit or loss [member] | Foreign exchange instruments [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets  
Measured at fair value on a recurring basis [member] | Level 3 [member] | Financial assets measured at fair value through profit or loss [member] | Interest rate instruments [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets  
Measured at fair value on a recurring basis [member] | Level 3 [member] | Financial assets measured at fair value through profit or loss [member] | Other [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 11,954 10,949  
Measured at fair value on a recurring basis [member] | Level 3 [member] | Financial assets measured at fair value through profit or loss [member] | Derivatives [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets 11,954 10,949  
Measured at fair value on a recurring basis [member] | Level 3 [member] | Financial assets measured at fair value through profit or loss [member] | Debt securities [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets   4,486  
Measured at fair value on a recurring basis [member] | Level 3 [member] | Financial assets measured at fair value through other comprehensive income [member] | Debt securities [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets  
Measured at fair value on a recurring basis [member] | Level 3 [member] | Financial assets measured at fair value through other comprehensive income [member] | Equity securities [member]      
Disclosures of fair value of financial assets and financial liabilities at amortized cost [Line items]      
Other financial assets ¥ 69,590 ¥ 50,183