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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, 2026
Mar. 31, 2025
Japanese plans    
Defined Benefit Plan Disclosure [Line Items]    
Net prior service credit ¥ 601 ¥ 666
Net actuarial gain (loss) 25,940 5,750
Net transition obligation 0 0
Total recognized in accumulated other comprehensive loss, pre-tax 26,541 6,416
Overseas plans    
Defined Benefit Plan Disclosure [Line Items]    
Net prior service credit (838) (502)
Net actuarial gain (loss) 17,953 12,865
Net transition obligation 9 8
Total recognized in accumulated other comprehensive loss, pre-tax ¥ 17,124 ¥ 12,371