| 附帯事業収益 | ja | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| 附帯事業収益、ガス事業 | ja | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| 附帯事業収益合計 | ja | http://www.xbrl.org/2003/role/totalLabel | http://www.xbrl.org/2003/role/link |
| Revenue from incidental businesses | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Revenue from incidental businesses - GAS | en | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| Total revenue from incidental businesses | en | http://www.xbrl.org/2003/role/totalLabel | http://www.xbrl.org/2003/role/link |