| その他事業収益 | ja | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| その他事業収益、海運業 | ja | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| その他事業収益合計 | ja | http://www.xbrl.org/2003/role/totalLabel | http://www.xbrl.org/2003/role/link |
| Other business revenue | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Other business revenue-WAT | en | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| Total other business revenue | en | http://www.xbrl.org/2003/role/totalLabel | http://www.xbrl.org/2003/role/link |