Consolidated Statement of Comprehensive Income (CAD) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Consolidated Statement of Comprehensive Income [Abstract]
Net income	3,167us-gaap_NetIncomeLoss	2,612us-gaap_NetIncomeLoss	2,680us-gaap_NetIncomeLoss
Foreign exchange gain (loss) on:
Foreign currency translation adjustments - pre-tax	75	46	(5)
Pension and other postretirement benefit plans:
Net Change Pension Other Postretirement Benefit Plans PreTax	(995)	1,775	(540)
Derivative instruments	1	0	0
Other comprehensive loss before income taxes	(921)	1,821	(545)
Income tax recovery (expense)	344us-gaap_OtherComprehensiveIncomeLossTax	(414)us-gaap_OtherComprehensiveIncomeLossTax	127us-gaap_OtherComprehensiveIncomeLossTax
Other comprehensive loss	(577)	1,407	(418)
Comprehensive income	2,590us-gaap_ComprehensiveIncomeNetOfTax	4,019us-gaap_ComprehensiveIncomeNetOfTax	2,262us-gaap_ComprehensiveIncomeNetOfTax

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Net Change in Pension and Other Postretirement Benefit Plans PreTax

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount before tax, after reclassification adjustments of other comprehensive income (loss).

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