| 債券貸借取引受入担保金の純増減(△) | ja | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| 債券貸借取引受入担保金の純増減(△)、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 increase (decrease) in cash collateral received for securities lent | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Net increase (decrease) in cash collateral received for securities lent - OpeCF - BNK | en | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |