| Gains (losses) on net movement in regulatory deferral account balances related to items that will be reclassified to profit or loss, before tax | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| The gains (losses) recognised in other comprehensive income on the net movement in regulatory deferral account balances that is related to items that will be reclassified to profit or loss, before tax. [Refer: Regulatory deferral account balances [member]; Other comprehensive income] | en | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |
| Ganhos (perdas) do movimento líquido nos saldos dos diferimentos regulamentares relacionados com os itens a serem reclassificados nos resultados, antes de impostos | pt | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Os ganhos (perdas) reconhecidos noutro rendimento integral do movimento líquido nos saldos dos diferimentos regulamentares relacionados com os itens a serem reclassificados nos resultados, antes de impostos. [Consultar: Saldos dos diferimentos regulamentares [member]; Outro rendimento integral] | pt | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |