Supplementary Information - Condensed Consolidating Financial Information (Details) - USD ($) $ in Billions	1 Months Ended
May 31, 2020	Jun. 30, 2020
ConocoPhillips [Member]
Condensed Financial Statements, Captions [Line Items]
Proceeds from Contributions from Affiliates	$ 2.2
Proceeds from Contributed Capital	0.8
ConocoPhillips Company [Member]
Condensed Financial Statements, Captions [Line Items]
Proceeds from Contributions from Affiliates	2.4
Proceeds from Contributed Capital	$ 0.8
ConocoPhillips Company [Member] \| ConocoPhillips [Member]
Condensed Financial Statements, Captions [Line Items]
Ownership Percentage by Parent		100.00%
Burlington Resources LLC [Member] \| ConocoPhillips Company [Member]
Condensed Financial Statements, Captions [Line Items]
Ownership Percentage by Parent		100.00%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

+ Details

Name:	srt_CondensedFinancialStatementsCaptionsLineItems
Namespace Prefix:	srt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash inflow associated with the amount received by a corporation from a shareholder during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3255-108585

+ Details

Name:	us-gaap_ProceedsFromContributedCapital
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash inflow from an entity that is affiliated with the entity by means of direct or indirect ownership.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3255-108585

+ Details

Name:	us-gaap_ProceedsFromContributionsFromAffiliates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	srt_ConsolidatedEntitiesAxis=srt_ParentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=cop_ConocophillipsCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=cop_ConocophillipsCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=cop_BurlingtonResourcesLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: