v3.26.1
Income Taxes - Summary of Income Tax Expense (Detail) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Disclosure of current and deferred tax expense benefit [Line items]      
Current income tax expense ¥ 1,472,925 ¥ 1,737,922 ¥ 2,056,433
Deferred income tax expense (benefit) (305,691) (113,087) (162,768)
Income tax expense 1,167,234 1,624,835 1,893,665
TMC and domestic subsidiaries [Member]      
Disclosure of current and deferred tax expense benefit [Line items]      
Current income tax expense 1,053,788 965,512 1,432,299
Deferred income tax expense (benefit) (376,104) (131,329) (42,906)
Foreign subsidiaries [Member]      
Disclosure of current and deferred tax expense benefit [Line items]      
Current income tax expense 419,137 772,410 624,134
Deferred income tax expense (benefit) ¥ 70,413 ¥ 18,242 ¥ (119,862)