v3.26.1
Business Segments (Reconciliation of Operating Profit (Loss) from Segments to Consolidated Statements of Income) (Detail) - JPY (¥)
¥ in Millions
12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]      
Operating profit: ¥ 2,365,400 ¥ 1,565,700 ¥ 1,831,400
Provision for credit losses (226,112) (121,790) (258,795)
Trading account losses—net (650,573) 32,262 (703,913)
Equity investment securities gains (losses)—net 151,388 (107,892) 113,216
Foreign exchange gains (losses)—net (636,227) 153,959 (296,487)
Equity in earnings of equity method investees—net 871,185 669,400 464,054
Impairment of goodwill (97,475) (150,089) 0
Impairment of intangible assets (8,417) (14,353) (15,042)
Reversal of (provision for) off-balance sheet credit instruments 23,310 727 (33,289)
Income before income tax expense 2,509,495 1,795,576 1,878,226
Fixed assets: 1,482,800 1,383,200 1,395,000
Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment      
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]      
Operating profit: 2,365,000 1,566,000 1,831,000
Provision for credit losses (226,000) (122,000) (259,000)
Trading account losses—net (644,000) (160,000) (1,073,000)
Equity investment securities gains (losses)—net 933,000 (706,000) 1,450,000
Debt investment securities gains (losses)—net (127,000) 828,000 300,000
Foreign exchange gains (losses)—net (433,000) 70,000 (426,000)
Equity in earnings of equity method investees—net 871,000 669,000 464,000
Impairment of goodwill (97,000) (150,000)  
Impairment of intangible assets (8,000) (14,000) (15,000)
Reversal of (provision for) off-balance sheet credit instruments 23,000 1,000 (33,000)
Other—net (148,000) (186,000) (361,000)
Income before income tax expense 2,509,000 1,796,000 1,878,000
Fixed assets: 3,126,000 2,881,000 2,664,000
U.S. GAAP adjustments and other 1,643,000 1,498,000 1,269,000
Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment | Japanese GAAP      
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]      
Fixed assets: ¥ 1,483,000 ¥ 1,383,000 ¥ 1,395,000