| Interest income on securities purchased under resale agreements | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Interest income on securities purchased under resale agreements - OI - BNK | en | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| Interest income on securities purchased under resale agreements | en | http://disclosure.edinet-fsa.go.jp/jppfs/bnk/role/label | http://www.xbrl.org/2003/role/link |
| 買現先利息 | ja | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| 買現先利息、経常収益、銀行業 | ja | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| (うち買現先利息) | ja | http://disclosure.edinet-fsa.go.jp/jppfs/bnk/role/label | http://www.xbrl.org/2003/role/link |