| 電気通信事業固定資産 | ja | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| 電気通信事業固定資産、電気通信事業 | ja | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| 電気通信事業固定資産合計 | ja | http://www.xbrl.org/2003/role/totalLabel | http://www.xbrl.org/2003/role/link |
| Non-current assets - telecommunications business | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Non-current assets - telecommunications business-ELC | en | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| Total non-current assets - telecommunications business | en | http://www.xbrl.org/2003/role/totalLabel | http://www.xbrl.org/2003/role/link |