Subsequent events - Additional Information (Detail) - Subsequent event [Member] ¥ in Billions	Dec. 05, 2022 JPY (¥) shares
Third quarter of the fiscal year ending March 31, 2023 [Member]
Subsequent Event [Line Items]
Expected pre-tax gain amount \| ¥	¥ 25
Nomura Research Institute Ltd [Member]
Subsequent Event [Line Items]
Number of ordinary shares sold by participating in a secondary offering \| shares	13,000,000

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

No definition available.

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Period Type:	duration