v3.26.3
Variable Interest Entities (Information about Non-consolidated VIEs) (Detail) - JPY (¥)
¥ in Millions
Sep. 30, 2026
Mar. 31, 2026
Variable Interest Entity [Line Items]    
Total assets ¥ 15,606,595 ¥ 18,002,776
Non Consolidated VIEs [Member]    
Variable Interest Entity [Line Items]    
Non-recourse loans 1,792 3,150
Investments 1,262,064 471,034
Maximum exposure to loss [1] 1,439,525 630,293
Non Consolidated VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]    
Variable Interest Entity [Line Items]    
Total assets 60,995,805 50,976,596
Acquisition of real estate and real estate development projects for customers | Non Consolidated VIEs [Member]    
Variable Interest Entity [Line Items]    
Non-recourse loans 1,792 3,150
Investments 15,949 13,387
Maximum exposure to loss [1] 38,415 33,342
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 1,769,017 1,657,776
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
Investment in securities | Non Consolidated VIEs [Member]    
Variable Interest Entity [Line Items]    
Non-recourse loans 0 0
Investments 1,165,191 382,322
Maximum exposure to loss [1] 1,297,622 501,574
Investment in securities | Non Consolidated VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]    
Variable Interest Entity [Line Items]    
Total assets 54,386,128 44,611,038
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 2,870 2,859
Maximum exposure to loss [1] 2,870 2,859
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 4,830 5,038
Securitization of loan receivable originated by third parties | Non Consolidated VIEs [Member]    
Variable Interest Entity [Line Items]    
Non-recourse loans 0 0
Investments 18,808 16,876
Maximum exposure to loss [1] 18,808 16,876
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 628,113 651,109
Power generation projects | Non Consolidated VIEs [Member]    
Variable Interest Entity [Line Items]    
Non-recourse loans 0 0
Investments 10,452 5,076
Maximum exposure to loss [1] 14,455 5,076
Power generation projects | Non Consolidated VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]    
Variable Interest Entity [Line Items]    
Total assets 57,673 24,427
Other VIEs | Non Consolidated VIEs [Member]    
Variable Interest Entity [Line Items]    
Non-recourse loans 0 0
Investments 48,794 50,514
Maximum exposure to loss [1] 67,355 70,566
Other VIEs | Non Consolidated VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]    
Variable Interest Entity [Line Items]    
Total assets ¥ 4,150,044 ¥ 4,027,208
[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.