v3.26.3
Estimated Fair Value of Financial Instruments (Information about Carrying Amount of Financial Instruments Reported in Consolidated Balance Sheets and Related Market or Fair Value) (Parenthetical) (Detail) - JPY (¥)
¥ in Millions
Sep. 30, 2026
Mar. 31, 2026
Estimated fair value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investment funds ¥ 182,674 ¥ 168,854