| 金融派生商品収益 | ja | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| 金融派生商品収益、経常収益、銀行業 | ja | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| (うち金融派生商品収益) | ja | http://disclosure.edinet-fsa.go.jp/jppfs/bnk/role/label | http://www.xbrl.org/2003/role/link |
| Income from derivatives other than for trading or hedging | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Income from derivatives other than for trading or hedging-OI-BNK | en | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| Income from derivatives other than for trading or hedging | en | http://disclosure.edinet-fsa.go.jp/jppfs/bnk/role/label | http://www.xbrl.org/2003/role/link |