| 債券貸借取引支払保証金の純増(△)減 | ja | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| 債券貸借取引支払保証金の純増(△)減、営業活動によるキャッシュ・フロー、銀行業 | ja | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| Net decrease (increase) in cash collateral provided for securities borrowed | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Net decrease (increase) in cash collateral provided for securities borrowed - OpeCF - BNK | en | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |