Effect of One Percent Change in Assumptions at Which Retirement Liabilities Could be Effectively Settled (Detail) (CAD) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Effect on net benefit cost, before tax, One percent increase - Rate of return on plan assets	(50)
Effect on net benefit cost, before tax, One percent increase - Discount rate	(80)
Effect on benefit obligation, One percent increase - Discount rate	(850)
Effect on net benefit cost, before tax, One percent increase- Rate of pay increases	50
Effect on benefit obligation, One percent increase - Rate of pay increases	170
Effect on net benefit cost, before tax, One percent decrease - Rate of return on plan assets	50
Effect on net benefit cost, before tax, One percent decrease - Discount rate	100
Effect on benefit obligation, One percent decrease - Discount rate	1,050
Effect on net benefit cost, before tax, One percent decrease- Rate of pay increases	(45)
Effect on benefit obligation, One percent decrease - Rate of pay increases	(150)