v3.26.1
Pension Plans (Funded Status of Defined Benefit Pension Plans) (Detail) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Japanese plans      
Change in benefit obligation:      
Benefit obligation at beginning of year ¥ 93,804 ¥ 105,109  
Service cost 4,473 5,078 ¥ 5,542
Interest cost 1,943 1,421 1,216
Actuarial loss (income) (6,728) (7,621)  
Plan participant's contributions 0 0  
Benefits paid (5,513) (5,032)  
Business combinations 4,141 86  
Divestitures (498) (1,937)  
Plan amendments 0 0  
Settlements 0 (3,300)  
Foreign currency exchange rate change 0 0  
Benefit obligation at end of year ¥ 91,622 ¥ 93,804 105,109
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration] Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax  
Change in plan assets:      
Fair value of plan assets at beginning of year ¥ 137,712 ¥ 143,101  
Actual return on plan assets 9,551 449  
Employer contribution 4,034 3,855  
Plan participant's contributions 0 0  
Benefits paid (4,560) (4,404)  
Business combinations 5,827 0  
Divestitures (460) (3,272)  
Settlements (1) (2,017)  
Foreign currency exchange rate change 0 0  
Fair value of plan assets at end of year 152,103 137,712 143,101
The funded status of the plans 60,481 43,908  
Amount recognized in the consolidated balance sheets consists of:      
Prepaid benefit cost included in other assets 75,053 59,111  
Accrued benefit liability included in other liabilities (14,572) (15,203)  
Net amount recognized 60,481 43,908  
Overseas plans      
Change in benefit obligation:      
Benefit obligation at beginning of year 122,744 129,934  
Service cost 2,890 3,268 2,999
Interest cost 4,786 4,091 3,395
Actuarial loss (income) (8,246) (11,712)  
Plan participant's contributions 471 233  
Benefits paid (4,025) (2,375)  
Business combinations 0 0  
Divestitures 0 0  
Plan amendments 0 179  
Settlements 0 0  
Foreign currency exchange rate change 15,504 (874)  
Benefit obligation at end of year ¥ 134,124 ¥ 122,744 129,934
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration] Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax  
Change in plan assets:      
Fair value of plan assets at beginning of year ¥ 151,819 ¥ 153,803  
Actual return on plan assets 2,115 (1,435)  
Employer contribution 2,665 2,446  
Plan participant's contributions 471 233  
Benefits paid (3,772) (2,182)  
Business combinations 0 0  
Divestitures 0 0  
Settlements 0 0  
Foreign currency exchange rate change 19,770 (1,046)  
Fair value of plan assets at end of year 173,068 151,819 ¥ 153,803
The funded status of the plans 38,944 29,075  
Amount recognized in the consolidated balance sheets consists of:      
Prepaid benefit cost included in other assets 40,886 30,809  
Accrued benefit liability included in other liabilities (1,942) (1,734)  
Net amount recognized ¥ 38,944 ¥ 29,075