v3.26.1
Common Stock and Capital Surplus (Narrative) (Detail) - JPY (¥)
2 Months Ended 3 Months Ended 5 Months Ended 12 Months Ended
Nov. 28, 2025
Nov. 29, 2024
Nov. 30, 2023
Jun. 30, 2024
Feb. 27, 2026
Jul. 31, 2025
Mar. 31, 2025
Mar. 31, 2024
Mar. 31, 2026
Nov. 14, 2025
May 15, 2025
Nov. 14, 2024
May 15, 2024
Nov. 14, 2023
Treasury Stock:                            
Treasury stock %                 5.00%          
Minimum                            
Common Stock and Capital Surplus Disclosure [Line Items]                            
Percentage of proceeds per issuance of common stock, including conversions of bonds and notes, to be credited to the common stock account                 50.00%          
Percentage of outstanding common stock issued as free share distribution prior to April 1, 1991                 5.00%          
Maximum                            
Common Stock and Capital Surplus Disclosure [Line Items]                            
Percentage of outstanding common stock issued as free share distribution prior to April 1, 1991                 10.00%          
Common stock | Maximum                            
Treasury Stock:                            
Aggregated number of shares allowed for repurchase (in shares)                   130,000,000 175,000,000 230,000,000 80,000,000 400,000,000
Aggregate amount of shares allowed for repurchase                   ¥ 250,000,000,000 ¥ 250,000,000,000 ¥ 300,000,000,000 ¥ 100,000,000,000 ¥ 400,000,000,000
Treasury stock common                            
Treasury Stock:                            
Number of own shares repurchased (in shares)       62,666,100 94,456,300 126,363,300 158,752,500 300,646,400            
Treasury shares value       ¥ 99,999,986,737 ¥ 249,999,908,452 ¥ 249,999,975,140 ¥ 299,999,995,801 ¥ 399,999,861,554            
Treasury shares cancelled (in shares) 200,000,000 270,000,000 350,000,000                      
BK and TB | Common stock                            
Common Stock and Capital Surplus Disclosure [Line Items]                            
Increase (decrease) by amount equal to the fair value of the shares issued by the application of U.S. accounting practices for issuance of free shares distribution made prior to April 1, 1991                 ¥ (1,910,106,000,000)          
BK and TB | Unappropriated retained earnings (Note 19):                            
Common Stock and Capital Surplus Disclosure [Line Items]                            
Increase (decrease) by amount equal to the fair value of the shares issued by the application of U.S. accounting practices for issuance of free shares distribution made prior to April 1, 1991                 ¥ 1,910,106,000,000