Gains and Losses on Asset Sales (Detail) - CAD CAD in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Investment And Other Income [Line Items]
Proceeds from asset sales		CAD 8	CAD 1,194	CAD 230	CAD 1,244
Book value of asset sales		2	285	12	292
Gain (loss) on asset sales, before tax	[1],[2]	6	909	219	952
Gain (loss) on asset sales, after tax	[1],[2]	CAD 5	CAD 774	CAD 191	CAD 808

[1] The nine months ended September 30, 2017 included a gain of $174 million ($151 million after tax) for the sale of a surplus property in Ontario.

[2] Third quarter and nine months ended September 30, 2016, included gains of $0.8 billion ($0.7 billion, after tax) from the sale of company-owned Esso retail sites in British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, Quebec, Nova Scotia and Newfoundland.