v3.25.2
Business Segments (Narrative) (Detail)
¥ in Billions
12 Months Ended
Mar. 31, 2025
JPY (¥)
segment
Mar. 31, 2024
JPY (¥)
Mar. 31, 2023
JPY (¥)
Segment Reporting Information [Line Items]      
Number of operating segments | segment 7    
Fixed assets: ¥ 1,383.2 ¥ 1,395.0 ¥ 1,368.1
Operating Segments | Customer business      
Segment Reporting Information [Line Items]      
Fixed assets: 813.1 778.4 731.6
Operating Segments | Retail & Digital Business Group | Customer business      
Segment Reporting Information [Line Items]      
Fixed assets: 267.5 243.8 215.2
Operating Segments | Retail & Digital Business Group | Customer business | Revision of prior period, reclassification, adjustment      
Segment Reporting Information [Line Items]      
Modification impact in operating profits (losses)   29.7 10.5
Fixed assets:   57.0 58.3
Modification impact in fixed assets   11.2 13.4
Modification impact In depreciation   8.6 4.7
Operating Segments | Global Corporate & Investment Banking Business Group | Customer business      
Segment Reporting Information [Line Items]      
Fixed assets: 160.9 170.9 171.9
Operating Segments | Global Corporate & Investment Banking Business Group | Customer business | Revision of prior period, reclassification, adjustment      
Segment Reporting Information [Line Items]      
Modification impact in operating profits (losses)   73.7  
Fixed assets:     0.7
Modification impact in fixed assets     0.1
Modification impact In depreciation   0.2 0.3
Operating Segments | Japanese Corporate & Investment Banking Business Group | Customer business      
Segment Reporting Information [Line Items]      
Fixed assets: 171.7 169.3 163.9
Operating Segments | Japanese Corporate & Investment Banking Business Group | Customer business | Revision of prior period, reclassification, adjustment      
Segment Reporting Information [Line Items]      
Modification impact in operating profits (losses)   63.4  
Fixed assets:   0.1 2.7
Modification impact in fixed assets     0.6
Modification impact In depreciation   0.4 0.9
Operating Segments | Commercial Banking & Wealth Management Business Group | Customer business      
Segment Reporting Information [Line Items]      
Fixed assets: 187.8 171.5 160.5
Operating Segments | Commercial Banking & Wealth Management Business Group | Customer business | Revision of prior period, reclassification, adjustment      
Segment Reporting Information [Line Items]      
Modification impact in operating profits (losses)   26.6 (10.5)
Fixed assets:   (57.1) (41.4)
Modification impact in fixed assets   11.3 10.8
Modification impact In depreciation   5.6 6.6
Operating Segments | Global Markets Business Group      
Segment Reporting Information [Line Items]      
Fixed assets: 87.8 114.3 113.1
Operating Segments | Global Markets Business Group | Customer business | Revision of prior period, reclassification, adjustment      
Segment Reporting Information [Line Items]      
Modification impact in operating profits (losses)   9.8  
Fixed assets:     2.5
Modification impact in fixed assets     0.2
Modification impact In depreciation   0.3 0.2
Operating Segments | Asset Management & Investor Services Business Group | Customer business      
Segment Reporting Information [Line Items]      
Fixed assets: 23.1 21.3 18.8
Operating Segments | Asset Management & Investor Services Business Group | Customer business | Revision of prior period, reclassification, adjustment      
Segment Reporting Information [Line Items]      
Modification impact in operating profits (losses)   3.7 0.1
Fixed assets:   0.1  
Modification impact In depreciation     0.1
Operating Segments | Global Commercial Banking Business Group | Customer business      
Segment Reporting Information [Line Items]      
Fixed assets: 2.1 1.6 1.3
Operating Segments | Global Commercial Banking Business Group | Customer business | Revision of prior period, reclassification, adjustment      
Segment Reporting Information [Line Items]      
Modification impact in operating profits (losses)   (0.5)  
Fixed assets:   0.1 0.2
Modification impact In depreciation   0.1  
Other      
Segment Reporting Information [Line Items]      
Fixed assets: ¥ 482.3 502.3 523.4
Other | Revision of prior period, reclassification, adjustment      
Segment Reporting Information [Line Items]      
Modification impact in operating profits (losses)   (194.9) 0.1
Fixed assets:     22.9
Modification impact in fixed assets     3.4
Modification impact In depreciation   ¥ 4.0 ¥ 0.6