Earnings per share (Narrative) (Details) - shares	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Basic earnings per share [abstract]
Weighted average stock options with potential future dilutive effect not included in calculation of diluted earnings per share	1,292,840
Diluted weighted average common shares outstanding	261,272,151	261,272,151

The description of instruments (including contingently issuable shares) that could potentially dilute basic earnings per share in the future, but were not included in the calculation of diluted earnings per share because they are antidilutive for the period(s) presented.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 33
-IssueDate 2019-01-01
-Paragraph 70
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=33&code=ifrs-tx-2019-en-r&anchor=para_70_c&doctype=Standard
-URIDate 2019-03-27

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration