Premises and Equipment - Additional Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Property, Plant and Equipment [Line Items]
Impairment losses	¥ 13,490	¥ 27,428
Depreciation and amortization	234,457	345,560	¥ 169,346
General and Administrative expenses
Property, Plant and Equipment [Line Items]
Impairment losses	6,813	8,910
Occupancy expenses
Property, Plant and Equipment [Line Items]
Impairment losses	6,677	18,518
Retail And Business Banking Company
Property, Plant and Equipment [Line Items]
Impairment losses	6,774	¥ 15,761
Impairment losses on real estate	¥ 5,587

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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The charge against earnings in the period to reduce the carrying amount of real property to fair value.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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