Other Long-Term Obligations (Parenthetical) (Detail) - CAD CAD in Millions	Dec. 31, 2015	Dec. 31, 2014
Schedule of Other Liabilities [Line Items]
Employee retirement benefits obligations in current liabilities	CAD 59	CAD 58
Asset retirement obligations and other environmental liabilities in current liabilities	CAD 116	CAD 143

For a classified balance sheet, the amount recognized in balance sheet as a current liability associated with an underfunded defined benefit plan.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Current Liabilities
-URI http://asc.fasb.org/extlink&oid=6509677

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=21915240&loc=d3e1703-114919

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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