Investment In Equity Security Fair Value

No definition available.

Name:	cop_InvestmentInEquitySecuritiesFairValue
Namespace Prefix:	cop_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Investment Shares Owned, Common Stock, percent of Issued and Outstanding

+ References

No definition available.

+ Details

Name:	cop_InvestmentOwnedCommonStockPercentOfIssuedAndOutstanding
Namespace Prefix:	cop_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Shares exchanged for assets held for sale.

+ References

No definition available.

+ Details

Name:	cop_SharesExchangeForAssetsHeldForSale
Namespace Prefix:	cop_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

+ Details

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

- Definition

Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(3)(d))
-URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=120269885&loc=SL75117546-209714

+ Details

Name:	us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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.

+ References

No definition available.

+ Details

Name:	us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

Name:	us-gaap_SharePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=cop_FosterCreekChristinaLakeFcclMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=cop_CenovusEnergyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Investment in Cenovus Energy - Textual (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2017
Schedule Of Available For Sale Securities [Line Items]
Unrealized (gain) loss on investment in Cenovus Energy	$ (308)	$ 1,691
Foster Creek Christina Lake (FCCL) [Member]
Schedule Of Available For Sale Securities [Line Items]
Equity Method Investment, Ownership Percentage			50.00%
Common Stock [Member] \| Cenovus Energy Common Stock [Member]
Schedule Of Available For Sale Securities [Line Items]
Shares Exchange for Assets Held for Sale			208
Investment Owned, Common Stock, percent of Issued and Outstanding	10.30%
Investment In Equity Security Fair Value	$ 1,560
Cenovus Energy common share price	$ 7.52
Unrealized (gain) loss on investment in Cenovus Energy	$ (308)	$ 1,691