Compensation Plans (Schedule Of Outstanding Deferred Share Units) (Details) - Canadian Dollar [Member] - Deferred Share Units [Member] - shares shares in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, Beginning of Year	920	753
Granted	134	139
Converted from HPR awards	16	43
Units, in Lieu of Dividends	5	6
Redeemed	(180)	(21)
Outstanding, End of Year	895	920

Number of rights issued during the period upon conversion from HPR awards on other than stock (or unit) option plans.

No definition available.

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- Definition

Share based compensation arrangement by share based payment award equity instruments other than options. Number of units issued in lieu of dividends.

+ References

No definition available.

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

Number of share options (or share units) exercised during the current period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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