| The amount of regulatory deferral account debit balances and the related deferred tax asset. [Refer: Regulatory deferral account debit balances; Deferred tax asset associated with regulatory deferral account balances] | en | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |
| Total regulatory deferral account debit balances and related deferred tax asset | en | http://www.xbrl.org/2003/role/totalLabel | http://www.xbrl.org/2003/role/link |
| Regulatory deferral account debit balances and related deferred tax asset | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |