v3.26.1
Variable Interest Entities (Information about Non-consolidated VIEs) (Detail) - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Variable Interest Entity [Line Items]      
Total assets ¥ 18,002,776 ¥ 16,866,251 ¥ 16,322,100
Non Consolidated VIEs [Member]      
Variable Interest Entity [Line Items]      
Non-recourse loans 193,594 136,227  
Investments 473,273 356,194  
Maximum exposure to loss [1] 822,976 622,655  
Non Consolidated VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]      
Variable Interest Entity [Line Items]      
Total assets 51,872,003 37,659,824  
Acquisition of real estate and real estate development projects for customers | Non Consolidated VIEs [Member]      
Variable Interest Entity [Line Items]      
Non-recourse loans 193,594 132,495  
Investments 13,854 11,224  
Maximum exposure to loss [1] 224,253 149,602  
Acquisition of real estate and real estate development projects for customers | Non Consolidated VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]      
Variable Interest Entity [Line Items]      
Total assets 2,402,850 1,859,420  
Acquisition of real estate for the Company and its subsidiaries' real estate-related business | Non Consolidated VIEs [Member]      
Variable Interest Entity [Line Items]      
Non-recourse loans 0 0  
Investments 0 0  
Maximum exposure to loss [1] 0 0  
Acquisition of real estate for the Company and its subsidiaries' real estate-related business | Non Consolidated VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]      
Variable Interest Entity [Line Items]      
Total assets 0 0  
Corporate rehabilitation support business | Non Consolidated VIEs [Member]      
Variable Interest Entity [Line Items]      
Non-recourse loans 0 0  
Investments 0 0  
Maximum exposure to loss [1] 0 0  
Corporate rehabilitation support business | Non Consolidated VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]      
Variable Interest Entity [Line Items]      
Total assets 0 0  
Investment in securities | Non Consolidated VIEs [Member]      
Variable Interest Entity [Line Items]      
Non-recourse loans 0 0  
Investments 384,074 272,927  
Maximum exposure to loss [1] 503,326 375,942  
Investment in securities | Non Consolidated VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]      
Variable Interest Entity [Line Items]      
Total assets 44,644,882 32,105,994  
Securitizing financial assets such as finance lease receivable and loan receivable | Non Consolidated VIEs [Member]      
Variable Interest Entity [Line Items]      
Non-recourse loans 0 0  
Investments 2,859 0  
Maximum exposure to loss [1] 2,859 0  
Securitizing financial assets such as finance lease receivable and loan receivable | Non Consolidated VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]      
Variable Interest Entity [Line Items]      
Total assets 5,038 0  
Securitization of loan receivable originated by third parties | Non Consolidated VIEs [Member]      
Variable Interest Entity [Line Items]      
Non-recourse loans 0 0  
Investments 16,876 16,437  
Maximum exposure to loss [1] 16,876 16,437  
Securitization of loan receivable originated by third parties | Non Consolidated VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]      
Variable Interest Entity [Line Items]      
Total assets 651,109 760,293  
Power generation projects | Non Consolidated VIEs [Member]      
Variable Interest Entity [Line Items]      
Non-recourse loans 0 0  
Investments 5,076 3,945  
Maximum exposure to loss [1] 5,076 5,195  
Power generation projects | Non Consolidated VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]      
Variable Interest Entity [Line Items]      
Total assets 24,427 19,499  
Other VIEs | Non Consolidated VIEs [Member]      
Variable Interest Entity [Line Items]      
Non-recourse loans 0 3,732  
Investments 50,534 51,661  
Maximum exposure to loss [1] 70,586 75,479  
Other VIEs | Non Consolidated VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]      
Variable Interest Entity [Line Items]      
Total assets ¥ 4,143,697 ¥ 2,914,618  
[1] Maximum exposure to loss includes remaining balance of commitments that could require the Company and its subsidiaries to provide investments or loans to the VIE.