v3.26.3
Write-Downs of Long-Lived Assets - Breakdowns of Recognized Impairment Losses for Difference between Carrying Amounts and Fair Values Reflected as Write-Downs of Long-Lived Assets (Detail)
¥ in Millions
 6 Months Ended
Sep. 30, 2026
JPY (¥)
Property
Sep. 30, 2025
JPY (¥)
Property
Impaired Long-Lived Assets Held and Used [Line Items]    
Write-downs of the assets held for sale, amount ¥ 19 ¥ 1,122
Write-downs of the assets held for sale, number of properties | Property
Write-downs due to decline in estimated future cash flows, amount ¥ 10,281 ¥ 275
Write-downs due to decline in estimated future cash flows, number of properties | Property  
Condominiums    
Impaired Long-Lived Assets Held and Used [Line Items]    
Write-downs of the assets held for sale, amount ¥ 3 ¥ 6
Write-downs of the assets held for sale, number of properties | Property 1 2
Commercial facilities other than office buildings    
Impaired Long-Lived Assets Held and Used [Line Items]    
Write-downs due to decline in estimated future cash flows, amount ¥ 46 ¥ 0
Write-downs due to decline in estimated future cash flows, number of properties | Property 2  
Others    
Impaired Long-Lived Assets Held and Used [Line Items]    
Write-downs of the assets held for sale, amount [1] ¥ 16 1,116
Write-downs due to decline in estimated future cash flows, amount [1] ¥ 10,235 ¥ 275
[1] For “Others,” the number of properties is omitted.