v3.26.1
Employee Benefits - Schedule of Breakdown of Fair Value of Plan Assets by Asset Class (Details) - JPY (¥)
¥ in Millions
Mar. 31, 2026
Mar. 31, 2025
Disclosure of fair value of plan assets [line items]    
Total plan assets ¥ 390,985 ¥ 347,123
With quoted prices in active markets    
Disclosure of fair value of plan assets [line items]    
Life insurance company general accounts 0 0
Cash and cash equivalent 16,727 11,070
Property 688 536
Other 4,316 1,104
Total plan assets 145,259 114,332
No quoted prices in active markets    
Disclosure of fair value of plan assets [line items]    
Life insurance company general accounts 79,709 68,741
Cash and cash equivalent 0 0
Property 27,665 18,036
Other 10,010 9,350
Total plan assets 245,726 232,791
Japan    
Disclosure of fair value of plan assets [line items]    
Total plan assets 224,045 221,422
Japan | With quoted prices in active markets    
Disclosure of fair value of plan assets [line items]    
Equities 8,910 10,531
Bonds 450 387
Japan | No quoted prices in active markets    
Disclosure of fair value of plan assets [line items]    
Equities 1,857 2,315
Bonds 23,112 19,513
Foreign    
Disclosure of fair value of plan assets [line items]    
Total plan assets 166,940 125,701
Foreign | With quoted prices in active markets    
Disclosure of fair value of plan assets [line items]    
Equities 75,471 57,690
Bonds 38,696 33,014
Foreign | No quoted prices in active markets    
Disclosure of fair value of plan assets [line items]    
Equities 71,794 81,589
Bonds ¥ 31,580 ¥ 33,246