v3.26.1
Fair Value Measurements (Information about Valuation Techniques and Significant Unobservable Inputs Used in Valuation of Level Three Assets Measured at Fair Value on Nonrecurring Basis) (Detail)
¥ in Millions
Mar. 31, 2026
JPY (¥)
Mar. 31, 2025
JPY (¥)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans held for sale ¥ 78,020 ¥ 97,694
Fair Value, Measurements, Nonrecurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans held for sale 838  
Real estate collateral-dependent loans (net of allowance for credit losses) 12,646 5,881
Investment in operating leases, property under facility operations and office facilities 11,907 8,105
Land and buildings undeveloped or under construction 2,203  
Equity method investments 5,140 20,619
Total 75,151 49,798
Fair Value, Measurements, Nonrecurring | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans held for sale 838  
Real estate collateral-dependent loans (net of allowance for credit losses) 12,646 5,881
Investment in operating leases, property under facility operations and office facilities 11,841 8,105
Land and buildings undeveloped or under construction 2,203  
Equity method investments 5,140 20,619
Total 32,668 34,605
Fair Value, Measurements, Nonrecurring | Level 3 | Direct capitalization    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Real estate collateral-dependent loans (net of allowance for credit losses) 1,093 1,064
Equity method investments ¥ 844  
Fair Value, Measurements, Nonrecurring | Level 3 | Direct capitalization | Capitalization rate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Certain equity method investments 0.075  
Fair Value, Measurements, Nonrecurring | Level 3 | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment in operating leases, property under facility operations and office facilities ¥ 6,283 ¥ 3,314
Land and buildings undeveloped or under construction ¥ 2,203  
Fair Value, Measurements, Nonrecurring | Level 3 | Discounted cash flows | Discount rate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Investment in operating leases, property under facility operations and office facilities   0.061
Significant unobservable inputs, Land and buildings undeveloped or under construction 0.039  
Fair Value, Measurements, Nonrecurring | Level 3 | Appraisals/Broker quotes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans held for sale ¥ 838  
Real estate collateral-dependent loans (net of allowance for credit losses) 11,553 ¥ 4,817
Investment in operating leases, property under facility operations and office facilities 5,558 4,791
Equity method investments 1,615 ¥ 20,619
Fair Value, Measurements, Nonrecurring | Level 3 | Market Multiples    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity method investments ¥ 2,681  
Fair Value, Measurements, Nonrecurring | Level 3 | Minimum | Direct capitalization | Capitalization rate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Real estate collateral-dependent loans (net of allowance for credit losses) 0.048 0.044
Fair Value, Measurements, Nonrecurring | Level 3 | Minimum | Discounted cash flows | Discount rate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Investment in operating leases, property under facility operations and office facilities 0  
Fair Value, Measurements, Nonrecurring | Level 3 | Minimum | Market Multiples | EV/EBITDA multiple    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Certain equity method investments 6.8  
Fair Value, Measurements, Nonrecurring | Level 3 | Maximum | Direct capitalization | Capitalization rate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Real estate collateral-dependent loans (net of allowance for credit losses) 0.062 0.052
Fair Value, Measurements, Nonrecurring | Level 3 | Maximum | Discounted cash flows | Discount rate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Investment in operating leases, property under facility operations and office facilities 0.053  
Fair Value, Measurements, Nonrecurring | Level 3 | Maximum | Market Multiples | EV/EBITDA multiple    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Certain equity method investments 7.8  
Fair Value, Measurements, Nonrecurring | Level 3 | Weighted Average | Direct capitalization | Capitalization rate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Real estate collateral-dependent loans (net of allowance for credit losses) 0.052 0.047
Significant unobservable inputs, Certain equity method investments 0.075  
Fair Value, Measurements, Nonrecurring | Level 3 | Weighted Average | Discounted cash flows | Discount rate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Investment in operating leases, property under facility operations and office facilities 0.052 0.061
Significant unobservable inputs, Land and buildings undeveloped or under construction 0.039  
Fair Value, Measurements, Nonrecurring | Level 3 | Weighted Average | Market Multiples | EV/EBITDA multiple    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Certain equity method investments 6.9