| Annexed detailed schedule of increase and decrease in non-current assets (part 2: intangible assets) | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Annexed detailed schedule of increase and decrease in non-current assets (part 2: intangible assets) - ELE [heading] | en | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| 固定資産期中増減明細表(無形固定資産再掲) | ja | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| 固定資産期中増減明細表(無形固定資産再掲)、電気事業 [目次項目] | ja | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |