Financial investments, Restructuring agreement of Abengoa (Details) - Ten West Link [Member]	9 Months Ended
Sep. 30, 2018 mi
Restructuring Agreement [Abstract]
Percentage interest acquired	12.50%
Length of transmission lines	114

The percentage of voting equity interests acquired in a business combination. [Refer: Business combinations [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 3
-IssueDate 2018-01-01
-Paragraph B64
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=3&date=2018-03-01&anchor=para_B64_c&doctype=Appendix&seq=2
-URIDate 2018-03-16

Name:	ifrs-full_PercentageOfVotingEquityInterestsAcquired
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant