Lease Transactions (Narrative) (Detail) - JPY (¥)
¥ in Millions
12 Months Ended
Mar. 31, 2022
Mar. 31, 2021
Leases [Abstract]    
Right-of-use assets of finance leases ¥ 12,980 ¥ 15,218
Lease liabilities of finance leases 16,104 20,137
Right-of-use assets of operating leases 261,803 338,547
Amount on balance sheet 384,183 476,104
Operating Lease, Impairment Loss ¥ 20,830 ¥ 56,424
Right-of-use assets of finance leases, in consolidated balance sheets line item Premises and equipment—net (Notes 5 and 7) Premises and equipment—net (Notes 5 and 7)
Lease liabilities of finance leases, in consolidated balance sheets line item Long-term debt (including ¥402,823 and ¥483,051 measured at fair value under the fair value option in 2021 and 2022) (Notes 7, 9, 12 and 31) Long-term debt (including ¥402,823 and ¥483,051 measured at fair value under the fair value option in 2021 and 2022) (Notes 7, 9, 12 and 31)
Right-of-use assets of operating leases, in consolidated balance sheets line item Other Assets Other Assets
Lease liabilities of operating leases, in consolidated balance sheets line item Other Liabilities Other Liabilities