v3.26.1
Financial Instruments - Schedule of Fair Value and Carrying Amount of Financial Assets and Financial Liabilities (Details) - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Disclosure of fair value measurement of assets [line items]    
Financial assets, Book value ¥ 3,071,287 ¥ 2,146,595
Deposits | Demand Deposits    
Disclosure of fair value measurement of assets [line items]    
Financial liabilities, Book value 2,090,486 1,688,643
Financial liabilities, Fair value 2,090,486 1,688,643
Deposits | Time Deposits    
Disclosure of fair value measurement of assets [line items]    
Financial liabilities, Book value 178,594 152,393
Financial liabilities, Fair value 178,319 152,222
Borrowings | Loan Payables    
Disclosure of fair value measurement of assets [line items]    
Financial liabilities, Book value 491,956 315,578
Financial liabilities, Fair value 486,206 310,261
Loan and Advances    
Disclosure of fair value measurement of assets [line items]    
Financial assets, Book value 2,289,805 1,483,416
Financial assets, Fair value 2,288,932 1,546,786
Financial liabilities, Book value 2,761,036 2,156,614
Financial liabilities, Fair value 2,755,011 2,151,126
Loan and Advances | Mortgage Loans    
Disclosure of fair value measurement of assets [line items]    
Financial assets, Book value 909,483 664,594
Financial assets, Fair value 908,513 673,236
Loan and Advances | Overdraft    
Disclosure of fair value measurement of assets [line items]    
Financial assets, Book value 312,255 261,943
Financial assets, Fair value 337,479 327,971
Loan and Advances | Other    
Disclosure of fair value measurement of assets [line items]    
Financial assets, Book value 16,879 383
Financial assets, Fair value 16,841 383
Securities | Japanese Government Bonds and Municipal Bonds    
Disclosure of fair value measurement of assets [line items]    
Financial assets, Book value 720,182 353,590
Financial assets, Fair value 704,074 346,444
Securities | Corporate and Other Debt Securities    
Disclosure of fair value measurement of assets [line items]    
Financial assets, Book value 328,535 200,015
Financial assets, Fair value 319,545 195,886
Securities | Asset Backed Securities    
Disclosure of fair value measurement of assets [line items]    
Financial assets, Book value 2,471 2,891
Financial assets, Fair value 2,480 2,866
Level 1 | Loan and Advances    
Disclosure of fair value measurement of assets [line items]    
Financial assets, Fair value 264,985 126,188
Level 1 | Securities | Japanese Government Bonds and Municipal Bonds    
Disclosure of fair value measurement of assets [line items]    
Financial assets, Fair value 264,985 126,188
Level 2 | Deposits | Demand Deposits    
Disclosure of fair value measurement of assets [line items]    
Financial liabilities, Fair value 2,090,486 1,688,643
Level 2 | Deposits | Time Deposits    
Disclosure of fair value measurement of assets [line items]    
Financial liabilities, Fair value 178,319 152,222
Level 2 | Borrowings | Loan Payables    
Disclosure of fair value measurement of assets [line items]    
Financial liabilities, Fair value 208,150 99,354
Level 2 | Loan and Advances    
Disclosure of fair value measurement of assets [line items]    
Financial assets, Fair value 758,634 416,142
Financial liabilities, Fair value 2,476,955 1,940,219
Level 2 | Securities | Japanese Government Bonds and Municipal Bonds    
Disclosure of fair value measurement of assets [line items]    
Financial assets, Fair value 439,089 220,256
Level 2 | Securities | Corporate and Other Debt Securities    
Disclosure of fair value measurement of assets [line items]    
Financial assets, Fair value 319,545 195,886
Level 3 | Borrowings | Loan Payables    
Disclosure of fair value measurement of assets [line items]    
Financial liabilities, Fair value 278,056 210,907
Level 3 | Loan and Advances    
Disclosure of fair value measurement of assets [line items]    
Financial assets, Fair value 1,265,313 1,004,456
Financial liabilities, Fair value 278,056 210,907
Level 3 | Loan and Advances | Mortgage Loans    
Disclosure of fair value measurement of assets [line items]    
Financial assets, Fair value 908,513 673,236
Level 3 | Loan and Advances | Overdraft    
Disclosure of fair value measurement of assets [line items]    
Financial assets, Fair value 337,479 327,971
Level 3 | Loan and Advances | Other    
Disclosure of fair value measurement of assets [line items]    
Financial assets, Fair value 16,841 383
Level 3 | Securities | Asset Backed Securities    
Disclosure of fair value measurement of assets [line items]    
Financial assets, Fair value ¥ 2,480 ¥ 2,866