| その他の特定取引費用 | ja | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| その他の特定取引費用、経常費用、銀行業 | ja | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| (うちその他の特定取引費用) | ja | http://disclosure.edinet-fsa.go.jp/jppfs/bnk/role/label | http://www.xbrl.org/2003/role/link |
| Net loss on other trading account transactions | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Net loss on other trading account transactions - OE - BNK | en | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| Net loss on other trading account transactions | en | http://disclosure.edinet-fsa.go.jp/jppfs/bnk/role/label | http://www.xbrl.org/2003/role/link |