v3.26.1
Income Taxes (Total Income Tax Expense Recognized) (Detail) - JPY (¥)
¥ in Millions
12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Income Tax Disclosure [Abstract]      
Provision for income taxes ¥ 233,103 ¥ 128,828 ¥ 131,388
Income tax expense (benefit) allocated to other comprehensive income (loss):      
Net change of unrealized gains (losses) on investment in securities (88,096) (60,260) (27,157)
Net change of impact of changes in policy liability discount rate 100,702 54,382 32,471
Net change of debt valuation adjustments 78 (13) (74)
Net change of defined benefit pension plans 7,711 2,063 5,554
Net change of foreign currency translation adjustments (12,045) 2,484 (30,992)
Net change of unrealized gains (losses) on derivative instruments 1,016 (441) (1,523)
Other direct adjustments to shareholders' equity 57 22 32
Total income tax expense ¥ 242,526 ¥ 127,065 ¥ 109,699