| 商品有価証券費用 | ja | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| 商品有価証券費用、経常費用、銀行業 | ja | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| (うち商品有価証券費用) | ja | http://disclosure.edinet-fsa.go.jp/jppfs/bnk/role/label | http://www.xbrl.org/2003/role/link |
| Net loss on trading securities | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Net loss on trading securities - OE - BNK | en | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| Net loss on trading securities | en | http://disclosure.edinet-fsa.go.jp/jppfs/bnk/role/label | http://www.xbrl.org/2003/role/link |