Premises and Equipment (Narrative) (Detail) - JPY (¥)
¥ in Millions
12 Months Ended
Mar. 31, 2022
Mar. 31, 2021
Mar. 31, 2020
Property, Plant and Equipment [Line Items]      
Impairment losses for long-lived assets ¥ 6,574 ¥ 11,424 ¥ 16,575
Impairment of assets held for sale 134,141 0 0
Real estate      
Property, Plant and Equipment [Line Items]      
Impairment of assets held for sale ¥ 58 ¥ 773 ¥ 194