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Pension Plans - Additional Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Japan
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligations for all defined benefit pension plans	¥ 95,069	¥ 98,880
Expected pension plans contribution by Company and certain subsidiaries in 2025	4,036
Cost recognized for defined contribution pension plans of Company and certain of its subsidiaries	¥ 2,146	¥ 2,100	¥ 1,997
Japan | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Portfolio of plans	30.00%	20.00%
Japan | Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Portfolio of plans	40.00%	50.00%
Japan | Other assets
Defined Benefit Plan Disclosure [Line Items]
Portfolio of plans	30.00%	30.00%
Overseas plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligations for all defined benefit pension plans	¥ 123,600	¥ 102,624
Other Foreign Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Expected pension plans contribution by Company and certain subsidiaries in 2025	2,432
Cost recognized for defined contribution pension plans of Company and certain of its subsidiaries	¥ 4,219	¥ 3,498	¥ 2,892
Other Foreign Benefit Plans | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Portfolio of plans	40.00%	40.00%
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
Defined Benefit Plan Disclosure [Line Items]
Portfolio of plans	10.00%	10.00%

X

- 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
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

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- Definition

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+ References

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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/exampleRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 18
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480482/715-20-55-18

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

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- Definition

Percentage of actual investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

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- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 70
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480794/715-70-50-1

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