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Pension Plans - Additional Information (Detail) - JPY (¥) ¥ in Millions | 12 Months Ended
--- | ---
Mar. 31, 2023 | Mar. 31, 2022 | Mar. 31, 2021
Japan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Accumulated benefit obligations for all defined benefit pension plans | ¥ 98,880 | ¥ 99,161 |
Expected pension plans contribution by Company and certain subsidiaries in 2024 | 4,121 |  |
Cost recognized for defined contribution pension plans of Company and certain of its subsidiaries | ¥ 2,100 | ¥ 1,997 | ¥ 1,873
Japan | Equity securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Portfolio of plans | 20.00% | 30.00% |
Japan | Debt Securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Portfolio of plans | 50.00% | 50.00% |
Japan | Other Plan Asset |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Portfolio of plans | 30.00% | 20.00% |
Overseas plans |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Accumulated benefit obligations for all defined benefit pension plans | ¥ 102,624 | ¥ 114,930 |
Other Foreign Benefit Plans |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Expected pension plans contribution by Company and certain subsidiaries in 2024 | 2,652 |  |
Cost recognized for defined contribution pension plans of Company and certain of its subsidiaries | ¥ 3,498 | ¥ 2,892 | ¥ 2,446
Other Foreign Benefit Plans | Equity securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Portfolio of plans | 40.00% | 50.00% |
Other Foreign Benefit Plans | Debt Securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Portfolio of plans | 50.00% | 50.00% |
Other Foreign Benefit Plans | Other Assets [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Portfolio of plans | 10.00% |  |

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- Definition Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (e) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 + Details
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- Definition Amount of contribution expected to be received by defined benefit plan from employer in next fiscal year following current fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (g) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 18 -URI https://asc.fasb.org/extlink&oid=123450688&loc=d3e4587-114921 + Details
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