Gains and Losses on Asset Sales (Parenthetical) (Detail) (CAD) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Investment And Other Income [Line Items]
Gain/(loss) on asset sales, before tax	150	[1]	94	[1]	197	[1]
Gain/(loss) on asset sales, after tax	120	[1]	72	[1]	153	[1]
Non-Operating Assets
Investment And Other Income [Line Items]
Gain/(loss) on asset sales, before tax	85
Gain/(loss) on asset sales, after tax	73

[1] 2013 included a gain of $85 million ($73 million after tax) for the sale of non-operating assets.