Lease Income (Operating Lease) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2021
Lessor, Lease, Description [Line Items]
Gains on sales of operating lease assets	¥ 56,932	¥ 40,148	¥ 26,358
Real Estate Asset
Lessor, Lease, Description [Line Items]
Gains on sales of operating lease assets	25,699	17,912	15,459
Operating Lease Assets Other than Real Estate
Lessor, Lease, Description [Line Items]
Gains on sales of operating lease assets	¥ 31,233	¥ 22,236	¥ 10,899

The net gain (loss) arising from the lessor's sale of assets held- or available-for-lease under contractual arrangements classified as operating leases.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 40
-Paragraph 3A
-URI https://asc.fasb.org/extlink&oid=126905841&loc=SL51729484-110225

Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 30
-Section 40
-Paragraph 8
-URI https://asc.fasb.org/extlink&oid=123393937&loc=d3e44908-112734

Name:	us-gaap_GainLossOnSaleOfLeasedAssetsNetOperatingLeases
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration