| Net movement in regulatory deferral account balances related to profit or loss and net movement in related deferred tax | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Total net movement in regulatory deferral account balances related to profit or loss and net movement in related deferred tax | en | http://www.xbrl.org/2003/role/totalLabel | http://www.xbrl.org/2003/role/link |
| The amount of the net movement in regulatory deferral account balances related to profit or loss and the net movement in related deferred tax. [Refer: Net movement in regulatory deferral account balances related to profit or loss; Net movement in deferred tax arising from regulatory deferral account balances related to profit or loss] | en | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |
| Variazioni nette dei saldi dei regulatory deferral account relative a utili o perdite e variazioni nette delle imposte differite correlate | it | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| L'ammontare delle variazioni nette dei saldi dei regulatory deferral account relative a utili o perdite e delle variazioni nette delle imposte differite correlate. [Rif: Variazioni nette dei saldi dei regulatory deferral account relative a utili o perdite; Variazioni nette delle imposte differite derivanti dai saldi dei regulatory deferral account relative a utili o perdite] | it | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |
| Totale variazioni nette dei saldi dei regulatory deferral account riguardanti utili o perdite e variazioni nette delle imposte differite correlate | it | http://www.xbrl.org/2003/role/totalLabel | http://www.xbrl.org/2003/role/link |