v3.26.1
Business Segments (Financial Information by Business Segment) (Detail) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Business segment information      
Net revenue: ¥ 5,991,300 ¥ 4,808,300 ¥ 4,750,200
Net interest income 3,684,254 3,088,197 2,624,923
Operating expenses 3,625,900 3,242,600 2,918,800
Operating profit (loss) 2,365,400 1,565,700 1,831,400
Fixed assets: 1,482,800 1,383,200 1,395,000
Increase in fixed assets 285,500 232,400 233,700
Depreciation 182,800 186,500 181,600
BK and TB      
Business segment information      
Net revenue: 3,145,400 2,152,800 2,566,000
Net interest income 1,913,900 1,756,900 1,616,900
Net fees 1,134,000 954,000 885,400
Other 97,500 (558,100) 63,700
Other than BK and TB      
Business segment information      
Net revenue: 2,845,900 2,655,500 2,184,200
Operating Segments | Customer business      
Business segment information      
Net revenue: 5,664,900 5,107,200 4,406,300
Operating expenses 3,143,600 2,860,100 2,520,400
Operating profit (loss) 2,521,300 2,247,100 1,885,900
Fixed assets: 899,100 813,100 778,400
Increase in fixed assets 209,500 167,300 176,200
Depreciation 150,100 143,200 136,500
Operating Segments | Customer business | BK and TB      
Business segment information      
Net revenue: 3,165,300 2,703,100 2,445,800
Net interest income 1,823,300 1,565,200 1,379,000
Net fees 1,173,200 993,500 918,600
Other 168,800 144,400 148,200
Operating Segments | Customer business | Other than BK and TB      
Business segment information      
Net revenue: 2,499,600 2,404,100 1,960,500
Operating Segments | Retail & Digital Business Group | Customer business      
Business segment information      
Net revenue: 1,064,600 941,700 842,600
Operating expenses 778,700 663,600 624,700
Operating profit (loss) 285,900 278,100 217,900
Fixed assets: 333,100 267,500 243,800
Increase in fixed assets 82,300 50,300 49,800
Depreciation 41,100 33,000 23,300
Operating Segments | Retail & Digital Business Group | Customer business | BK and TB      
Business segment information      
Net revenue: 458,000 390,200 319,400
Net interest income 365,400 307,400 248,100
Net fees 87,700 78,800 67,200
Other 4,900 4,000 4,100
Operating Segments | Retail & Digital Business Group | Customer business | Other than BK and TB      
Business segment information      
Net revenue: 606,600 551,500 523,200
Operating Segments | Commercial Banking & Wealth Management Business Group | Customer business      
Business segment information      
Net revenue: 866,900 727,200 626,800
Operating expenses 458,900 429,200 407,500
Operating profit (loss) 408,000 298,000 219,300
Fixed assets: 199,900 187,800 171,500
Increase in fixed assets 44,800 37,200 35,800
Depreciation 24,200 21,000 19,000
Operating Segments | Commercial Banking & Wealth Management Business Group | Customer business | BK and TB      
Business segment information      
Net revenue: 619,500 499,700 420,300
Net interest income 366,200 268,000 199,500
Net fees 214,400 195,000 187,300
Other 38,900 36,700 33,500
Operating Segments | Commercial Banking & Wealth Management Business Group | Customer business | Other than BK and TB      
Business segment information      
Net revenue: 247,400 227,500 206,500
Operating Segments | Japanese Corporate & Investment Banking Business Group | Customer business      
Business segment information      
Net revenue: 1,125,900 1,024,700 974,700
Operating expenses 418,900 388,100 371,000
Operating profit (loss) 707,000 636,600 603,700
Fixed assets: 176,600 171,700 169,300
Increase in fixed assets 44,800 45,000 46,100
Depreciation 40,600 42,200 42,500
Operating Segments | Japanese Corporate & Investment Banking Business Group | Customer business | BK and TB      
Business segment information      
Net revenue: 923,300 835,800 795,300
Net interest income 539,900 512,300 488,700
Net fees 307,400 253,700 234,100
Other 76,000 69,800 72,500
Operating Segments | Japanese Corporate & Investment Banking Business Group | Customer business | Other than BK and TB      
Business segment information      
Net revenue: 202,600 188,900 179,400
Operating Segments | Global Commercial Banking Business Group | Customer business      
Business segment information      
Net revenue: 904,200 969,300 684,800
Operating expenses 516,600 531,300 382,300
Operating profit (loss) 387,600 438,000 302,500
Fixed assets: 2,400 2,100 1,600
Increase in fixed assets 900 600 500
Depreciation 300 300 300
Operating Segments | Global Commercial Banking Business Group | Customer business | BK and TB      
Business segment information      
Net revenue: 34,000 27,000 29,100
Net interest income 35,800 28,000 29,300
Net fees (1,700) (900) (100)
Other (100) (100) (100)
Operating Segments | Global Commercial Banking Business Group | Customer business | Other than BK and TB      
Business segment information      
Net revenue: 870,200 942,300 655,700
Operating Segments | Asset Management & Investor Services Business Group | Customer business      
Business segment information      
Net revenue: 621,800 534,200 432,300
Operating expenses 469,300 398,700 311,000
Operating profit (loss) 152,500 135,500 121,300
Fixed assets: 23,600 23,100 21,300
Increase in fixed assets 8,200 7,700 11,500
Depreciation 7,800 7,600 9,100
Operating Segments | Asset Management & Investor Services Business Group | Customer business | BK and TB      
Business segment information      
Net revenue: 159,700 139,300 118,600
Net interest income 38,700 25,800 14,700
Net fees 121,100 113,500 103,800
Other (100) 0 100
Operating Segments | Asset Management & Investor Services Business Group | Customer business | Other than BK and TB      
Business segment information      
Net revenue: 462,100 394,900 313,700
Operating Segments | Global Corporate & Investment Banking Business Group | Customer business      
Business segment information      
Net revenue: 1,081,500 910,100 845,100
Operating expenses 501,200 449,200 423,900
Operating profit (loss) 580,300 460,900 421,200
Fixed assets: 163,500 160,900 170,900
Increase in fixed assets 28,500 26,500 32,500
Depreciation 36,100 39,100 42,300
Operating Segments | Global Corporate & Investment Banking Business Group | Customer business | BK and TB      
Business segment information      
Net revenue: 970,800 811,100 763,100
Net interest income 477,300 423,700 398,700
Net fees 444,300 353,400 326,300
Other 49,200 34,000 38,100
Operating Segments | Global Corporate & Investment Banking Business Group | Customer business | Other than BK and TB      
Business segment information      
Net revenue: 110,700 99,000 82,000
Operating Segments | Global Markets Business Group      
Business segment information      
Net revenue: 306,900 (339,500) 302,400
Operating expenses 342,400 318,300 297,300
Operating profit (loss) (35,500) (657,800) 5,100
Fixed assets: 95,400 87,800 114,300
Increase in fixed assets 34,200 25,500 28,200
Depreciation 23,300 30,300 32,800
Operating Segments | Global Markets Business Group | BK and TB      
Business segment information      
Net revenue: (18,700) (622,300) 12,200
Net interest income 56,700 103,100 85,500
Net fees (15,300) (24,800) (13,300)
Other (60,100) (700,600) (60,000)
Operating Segments | Global Markets Business Group | Other than BK and TB      
Business segment information      
Net revenue: 325,600 282,800 290,200
Other      
Business segment information      
Net revenue: 19,500 40,600 41,500
Operating expenses 139,900 64,200 101,100
Operating profit (loss) (120,400) (23,600) (59,600)
Fixed assets: 488,300 482,300 502,300
Increase in fixed assets 41,800 39,600 29,300
Depreciation 9,400 13,000 12,300
Other | Subsidiaries      
Business segment information      
Fixed assets: 1,890,500 1,732,500 1,505,400
Other | BK and TB      
Business segment information      
Net revenue: (1,200) 72,000 108,000
Net interest income 33,900 88,600 152,400
Net fees (23,900) (14,700) (19,900)
Other (11,200) (1,900) (24,500)
Other | Other than BK and TB      
Business segment information      
Net revenue: ¥ 20,700 ¥ (31,400) ¥ (66,500)