Description of Business and Segmented Disclosures - Schedule of Capital Expenditures (Parenthetical) (Detail) $ in Millions	May 17, 2017 CAD ($)
Disclosure Of Business Combinations [Abstract]
Carrying value of pre-existing interest	$ 9,081
Estimated fair value	$ 11,605

Acquisition date carrying value of FCCL partnership property, plant and equipment, net and exploration and evaluation assets.

No definition available.

Name:	cve_AcquisitionDateCarryingValueOfFCCLPartnershipPropertyPlantAndEquipmentNetAndExplorationAndEvaluationAssets
Namespace Prefix:	cve_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration