Unrecognized Tax Benefits (Detail) (CAD) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Unrecognized Tax Benefits [Line Items]
January 1 balance	143	134	147
Additions based on current year's tax position	10	4
Additions for prior years' tax positions	2	10	20
Reductions for prior years' tax positions	(4)	(3)	(31)
Reductions due to lapse of the statute of limitations		(2)	(2)
December 31 balance	151	143	134