Schedule of Unconditional Purchase Obligations (Parenthetical) (Detail) (CAD) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Unrecorded Unconditional Purchase Obligation [Line Items]
Undiscounted obligations mainly pertaining to pipeline throughput agreements	657	[1]
Total payments under unconditional purchase obligations	95		86	73
Imputed interest on commitments	178
Total present value of commitments excluding imputed interest	479

[1] Undiscounted obligations of $657 million mainly pertain to pipeline throughput agreements. Total payments under unconditional purchase obligations were $95 million (2012 - $86 million, 2011 - $73 million). The present value of these commitments, excluding imputed interest of $178 million, totalled $479 million.