v3.26.3
Fair Value Measurements (Recorded Amounts of Major Assets Measured at Fair Value on Nonrecurring Basis) (Detail) - JPY (¥)
¥ in Millions
Sep. 30, 2026
Mar. 31, 2026
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans held for sale ¥ 60,859 ¥ 78,020
Fair Value, Measurements, Nonrecurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans held for sale 1,747 838
Real estate collateral-dependent loans (net of allowance for credit losses) 5,489 11,553
Investment in operating leases, property under facility operations and office facilities 8,517 11,907
Land and buildings undeveloped or under construction   2,203
Equity securities 9,789 42,417
Equity method investments 43,128 5,140
Total 68,670 74,058
Fair Value, Measurements, Nonrecurring | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans held for sale 0 0
Real estate collateral-dependent loans (net of allowance for credit losses) 0 0
Investment in operating leases, property under facility operations and office facilities 0 0
Land and buildings undeveloped or under construction   0
Equity securities 0 0
Equity method investments 31,291 0
Total 31,291 0
Fair Value, Measurements, Nonrecurring | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans held for sale 1,747 0
Real estate collateral-dependent loans (net of allowance for credit losses) 0 0
Investment in operating leases, property under facility operations and office facilities 0 66
Land and buildings undeveloped or under construction   0
Equity securities 9,789 42,417
Equity method investments 0 0
Total 11,536 42,483
Fair Value, Measurements, Nonrecurring | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans held for sale 0 838
Real estate collateral-dependent loans (net of allowance for credit losses) 5,489 11,553
Investment in operating leases, property under facility operations and office facilities 8,517 11,841
Land and buildings undeveloped or under construction   2,203
Equity securities 0 0
Equity method investments 11,837 5,140
Total ¥ 25,843 ¥ 31,575