Discontinued operations - Additional Information (Detail) - JPY (¥) ¥ in Millions |
Oct. 01, 2025 |
Sep. 30, 2025 |
|---|---|---|
| Disclosure of Results of Operations From Discontinued Operations [Line Items] | ||
| Proportion of ownership interest in subsidiary | 16.40% | |
| Accumulated other comprehensive income | ¥ 263,298 | |
| Accumulated other comprehensive income loss | 1,640,079 | |
| Discontinued operations [member] | ||
| Disclosure of Results of Operations From Discontinued Operations [Line Items] | ||
| Accumulated other comprehensive income directly related to the disposal group classified as held for distribution to owners | 1,377,795 | |
| Excess amount of equity interest in the net fair value of identifiable assets and liabilities | 188,888 | |
| Impairment loss of investments accounted for using the equity method | ¥ 188,888 |