v3.25.2
Financial instruments - Summary of Income and Expenses Related to Financial Instruments in the Financial Services Segment (Detail) - JPY (¥)
¥ in Millions
 12 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Mar. 31, 2023
Income      
Dividend income ¥ 0 ¥ 122  
Financial Services [Member]      
Income      
Net gains (losses) recognized in profit or loss 5,219 [1] 894,543 ¥ 43,617
Total interest income 262,551 [1] 243,269 223,306
Dividend income 186 [1] 459 195
Expenses      
Total interest expenses 79,366 72,488 29,867
Impairment losses (gains) on financial assets (74) (45) 152
Financial Services [Member] | Financial instruments required to be measured at FVPL [member]      
Income      
Net gains (losses) recognized in profit or loss 149,946 [1],[2] 857,653 56,150
Financial Services [Member] | Financial liabilities measured at AC [member]      
Income      
Net gains (losses) recognized in profit or loss 14,830 [1] (105,974) (58,484)
Expenses      
Total interest expenses 79,366 72,488 29,867
Financial Services [Member] | Financial instruments designated to be measured at FVPL [member]      
Income      
Net gains (losses) recognized in profit or loss (123,876) [1] (120,317) (109,480)
Financial Services [Member] | Financial assets measured at AC [member]      
Income      
Net gains (losses) recognized in profit or loss 12,969 [1] 5,279 14,242
Total interest income 59,507 [1] 52,060 38,787
Expenses      
Impairment losses (gains) on financial assets (91) (42) 144
Financial Services [Member] | Debt instruments measured at FVOCI [member]      
Income      
Net gains (losses) recognized in profit or loss (48,650) [1] 257,902 141,189
Total interest income 203,044 [1] 191,209 184,519
Expenses      
Impairment losses (gains) on financial assets 17 (3) 8
Financial Services [Member] | Equity instruments measured at FVOCI [member]      
Income      
Dividend income ¥ 186 [1] ¥ 459 ¥ 195
[1] Income includes investment returns which occurred in the insurance business. Refer to Note 13.
[2] Financial instruments required to be measured at FVPL include the fair value changes attributable to the hedged risks of debt instruments measured at fair value through other comprehensive income designated as the hedged items in fair value hedges.