Premises and equipment-Summary of Premises and Equipment (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2020	Mar. 31, 2019
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	¥ 3,318,686	¥ 3,363,162
Less: Accumulated depreciation and amortization	1,462,438	1,462,210
Premises and equipment—net	1,856,248	1,900,952
Land
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	557,943	563,032
Buildings
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	657,774	826,781
Equipment and furniture
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	442,302	472,186
Leasehold improvements
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	228,383	97,508
Construction in Progress
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	73,164	37,174
Software
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	¥ 1,359,120	¥ 1,366,481

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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