| 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 receivables under securities borrowing transactions | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Net decrease (increase) in receivables under securities borrowing transactions-OpeCF-BNK | en | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |