Business combinations - Business Combination, Recognized Asset Acquired and Liability Assumed (Detail) - JPY (¥) ¥ in Millions |
Mar. 31, 2026 |
Dec. 01, 2025 |
Mar. 31, 2025 |
Mar. 31, 2024 |
|---|---|---|---|---|
| Business Combination [Line Items] | ||||
| Goodwill | ¥ 172,492 | ¥ 17,199 | ¥ 19,260 | |
| Deferred tax assets | ¥ 10,479 | |||
| Deferred tax liabilities | (11,820) | |||
| Macquarie Management Holdings Inc [Member] | ||||
| Business Combination [Line Items] | ||||
| Goodwill | 150,976 | |||
| Investments in equity securities for other than operating purposes | 31,334 | |||
| Other assets | 17,579 | |||
| Deferred tax assets | 11,389 | |||
| Other liabilities | (9,694) | |||
| Employee Liabilities | (16,799) | |||
| Deferred tax liabilities | (26,001) | |||
| Total consideration, net of cash acquired | 276,985 | |||
| Client relationships [Member] | Macquarie Management Holdings Inc [Member] | ||||
| Business Combination [Line Items] | ||||
| Finite-lived intangible assets | 113,510 | |||
| Software [Member] | Macquarie Management Holdings Inc [Member] | ||||
| Business Combination [Line Items] | ||||
| Finite-lived intangible assets | ¥ 4,691 |
| X | ||||||||||
- Definition Business combination recognized identifiable assets acquired and liabilities assumed employee liabilities. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount of investment in debt and equity securities acquired in business combination and recognized at acquisition date, classified as current. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount of asset acquired in business combination and recognized at acquisition date, classified as other and current. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount of liability assumed in business combination and recognized at acquisition date, classified as other and current. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount of deferred tax asset acquired in business combination and recognized at acquisition date. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount of deferred tax liability assumed in business combination and recognized at acquisition date. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount of identifiable finite-lived intangible asset acquired in business combination and recognized at acquisition date. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount of asset acquired in excess of (less than) liability assumed plus goodwill in business combination and recognized at acquisition date. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount, after accumulated impairment loss, of asset representing future economic benefit arising from other asset acquired in business combination or from joint venture formation or both, that is not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|