Onerous Contract Provisions - Summary of Onerous Contract Provisions (Detail) - CAD ($) $ in Millions	6 Months Ended
Jun. 30, 2019	Dec. 31, 2018
Onerous Contracts Provision [Abstract]
Onerous Contract Provision as at January 1, 2019	$ 78
Liabilities Settled	(6)
Change in Assumptions	(11)
Change in Discount Rate	4
Unwinding of Discount on Onerous Contract Provisions	2
Onerous Contract Provisions, End of Year	67
Less: Current Portion	16	$ 50
Long-Term Portion	$ 51	$ 613

Onerous contract increase decrease in assumptions.

No definition available.

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Namespace Prefix:	cve_
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Balance Type:	credit
Period Type:	duration

- Definition

Onerous contract increase decrease in discount rate.

+ References

No definition available.

+ Details

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Namespace Prefix:	cve_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Onerous contract liabilities settled.

+ References

No definition available.

+ Details

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

- Definition

Onerous contract unwinding of discount.

+ References

No definition available.

+ Details

Name:	cve_OnerousContractUnwindingOfDiscount
Namespace Prefix:	cve_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of non-current provision for onerous contracts. [Refer: Onerous contracts provision]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Note Expiry date 2019-01-01
-Name IAS
-Number 37
-IssueDate 2018-01-01
-Section Example 8 An onerous contract
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=37&date=2018-03-02&anchor=sect_Example8Anonerouscontract&doctype=Illustrative%20Examples&book=b
-URIDate 2018-03-16

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 37
-IssueDate 2018-01-01
-Paragraph 66
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=37&date=2018-03-01&anchor=para_66&doctype=Standard
-URIDate 2018-03-16

+ Details

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Period Type:	instant

- Definition

The amount of provision for onerous contracts. An onerous contract is a contract in which the unavoidable costs of meeting the obligation under the contract exceed the economic benefits expected to be received under it. [Refer: Other provisions]

+ References

+ Details

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Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

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- Definition

The amount of current provision for onerous contracts. [Refer: Onerous contracts provision]

+ References

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant