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Business Acquisitions - Schedule of Supplemental Pro Forma Data (Details) - ITC - CAD CAD in Millions | 12 Months Ended
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Dec. 31, 2016 | Dec. 31, 2015
Business Acquisition [Line Items] |  |
Pro forma revenue | CAD 7,995 | CAD 8,093
Pro forma net earnings attributable to common equity shareholders | CAD 919 | CAD 937

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- Definition The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(2)-(3) -URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1392-128463 + Details
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