Income Tax Expense/(Credit) for Components of Other Comprehensive Income (Detail) (CAD) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Line Items]
Post-retirement benefits liability adjustment (excluding amortization)	185	(155)	(326)
Amortization of post-retirement benefits liability adjustment included in net periodic benefit cost	71	68	47
Total	256	(87)	(279)