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Pension Plans (Defined Benefit Plan Amount Recognized in Accumulated Other Comprehensive Income (Loss), Pre-tax) (Detail) - JPY (¥) ¥ in Millions | Mar. 31, 2025 | Mar. 31, 2024
--- | --- | ---
Japan |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Net prior service credit | ¥ 666 | ¥ 1,016
Net actuarial gain (loss) | 5,750 | 866
Net transition obligation | 0 | 0
Total recognized in accumulated other comprehensive loss, pre-tax | 6,416 | 1,882
Overseas plans |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Net prior service credit | (502) | (28)
Net actuarial gain (loss) | 12,865 | 9,735
Net transition obligation | 8 | 7
Total recognized in accumulated other comprehensive loss, pre-tax | ¥ 12,371 | ¥ 9,714

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- Definition Amount, before tax, of accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -Publisher FASB -URI https://asc.fasb.org/1943274/2147482790/220-10-45-14A Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (j) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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