v3.26.1
Intangible Assets - Changes in Cost, Accumulated Amortization and Impairment Losses, and Carrying Amounts of Intangible Assets (Detail) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]    
Beginning balance ¥ 1,126,019  
Additions
Internally developed
Ending balance 784,760 1,126,019
Cost [member]    
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]    
Beginning balance 2,115,223 1,830,172
Additions 28,995 22,483
Internally developed 260,086 342,873
Sales or disposal (599,527) (78,833)
Exchange differences on translating foreign operations 55,698 (8,646)
Other (3,519) 7,174
Ending balance 1,856,956 2,115,223
Accumulated amortization and impairment losses [member]    
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]    
Beginning balance (989,204) (830,483)
Amortization (208,790) (204,136)
Impairment losses (104,152)  
Sales or disposal 255,494 43,550
Exchange differences on translating foreign operations (33,544) 3,779
Other 8,000 (1,914)
Ending balance (1,072,196) (989,204)
Capitalized development costs [member]    
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]    
Beginning balance 841,131  
Ending balance 488,048 841,131
Capitalized development costs [member] | Cost [member]    
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]    
Beginning balance 1,338,894 1,101,561
Internally developed 198,806 287,098
Sales or disposal (539,135) (50,588)
Exchange differences on translating foreign operations 16,219 (793)
Other 1,756 1,616
Ending balance 1,016,540 1,338,894
Capitalized development costs [member] | Accumulated amortization and impairment losses [member]    
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]    
Beginning balance (497,763) (372,370)
Amortization (165,607) (162,579)
Impairment losses (69,602)  
Sales or disposal 209,740 37,207
Exchange differences on translating foreign operations (8,758) (39)
Other 3,498 18
Ending balance (528,492) (497,763)
Software [member]    
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]    
Beginning balance 189,931  
Ending balance 238,369 189,931
Software [member] | Cost [member]    
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]    
Beginning balance 666,805 597,982
Additions 26,064 20,330
Internally developed 61,280 55,775
Sales or disposal (50,744) (6,880)
Exchange differences on translating foreign operations 30,460 (5,754)
Other (4,245) 5,352
Ending balance 729,620 666,805
Software [member] | Accumulated amortization and impairment losses [member]    
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]    
Beginning balance (476,874) (445,892)
Amortization (40,769) (40,549)
Impairment losses (217)  
Sales or disposal 45,731 6,041
Exchange differences on translating foreign operations (21,879) 3,650
Other 2,757 (124)
Ending balance (491,251) (476,874)
Other [member]    
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]    
Beginning balance 94,957  
Ending balance 58,343 94,957
Other [member] | Cost [member]    
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]    
Beginning balance 109,524 130,629
Additions 2,931 2,153
Sales or disposal (9,648) (21,365)
Exchange differences on translating foreign operations 9,019 (2,099)
Other (1,030) 206
Ending balance 110,796 109,524
Other [member] | Accumulated amortization and impairment losses [member]    
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]    
Beginning balance (14,567) (12,221)
Amortization (2,414) (1,008)
Impairment losses (34,333)  
Sales or disposal 23 302
Exchange differences on translating foreign operations (2,907) 168
Other 1,745 (1,808)
Ending balance ¥ (52,453) ¥ (14,567)