Summary of Assets Acquired and Liabilities Assumed (Detail) (CAD) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Feb. 26, 2013 Celtic
Business Acquisition [Line Items]
Cash			6
Accounts receivable			38
Materials, supplies and prepaid expenses			5
Property, plant and equipment			2,045	[1]
Goodwill	224	204	20	[2]
Total assets acquired			2,114
Accounts payable and accrued liabilities			62
Deferred income tax liabilities			377	[3]
Other long-term obligations			67
Total liabilities assumed			506
Net assets acquired			1,608

[1] Property, plant and equipment were measured primarily using an income approach. The fair value measurements of the oil and gas assets were based, in part, on significant inputs not observable in the market and thus represent a Level 3 measurement. The significant inputs included Celtic resources, assumed future production profiles, commodity prices (mainly based on observable market inputs), risk adjusted discount rate of 10 percent, inflation of 2 percent and assumptions on the timing and amount of future development and operating costs. The property, plant and equipment additions were segmented to the Upstream business, with all of the assets in Canada.

[2] Goodwill was the excess of the consideration transferred over the net assets recognized and represents the future economic benefits arising from other assets acquired that could not be individually identified and separately recognized. Goodwill was recognized in the Upstream reporting unit. Goodwill is not amortized and is not deductible for tax purposes.

[3] Deferred income taxes reflect the future tax consequences on the temporary differences between the amount of assets and liabilities recognized for financial reporting purposes and such amounts recognized for tax purposes. The deferred income taxes recorded as part of the acquisition were: