v3.26.1
Employee Benefits - Schedule of Changes in Effect of Asset Ceiling (Details) - JPY (¥)
¥ in Millions
12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Disclosure of fair value of plan assets [line items]    
Balance at beginning of the year ¥ (116,083)  
Balance at end of the year (127,576) ¥ (116,083)
Effect of asset ceiling    
Disclosure of fair value of plan assets [line items]    
Balance at beginning of the year 78,717 63,422
Interest income 1,897 1,059
Remeasurement Changes in effect of asset ceiling 17,792 14,237
Balance at end of the year ¥ 98,407 ¥ 78,717