Identification of the specific currency to be purchased upon settlement or exercise of the foreign currency derivative.

No definition available.

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- Definition

Identification of the specific currency to be sold upon settlement or exercise of the foreign currency derivative.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeCurrencySold
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Data Type:	xbrli:stringItemType
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- Definition

The strike price on the foreign currency option contract such as a put option or a call option.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeForeignCurrencyOptionStrikePrice
Namespace Prefix:	us-gaap_
Data Type:	srt-types:perUnitItemType
Balance Type:	na
Period Type:	instant

- Definition

Contractual rate at which a foreign currency can be purchased or sold.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeForwardExchangeRate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeNotionalAmount
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Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

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- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=cop_BuyBritishPoundSellOtherCurrenciesMember
Namespace Prefix:
Data Type:	na
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- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=cop_SellCanadianDollarBuyUSDollarMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_HedgingDesignationAxis=us-gaap_NondesignatedMember
Namespace Prefix:
Data Type:	na
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Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=cop_BuyCanadianDollarCurrencySellUnitedStatesCurrencyMember
Namespace Prefix:
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Derivative and Financial Instruments - FX Notional (Details) £ in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020 CAD ($) $ / $	Jun. 30, 2019 CAD ($) $ / $	Mar. 31, 2020 GBP (£) $ / $	Dec. 31, 2019 CAD ($)	Dec. 31, 2019 GBP (£)
Buy British Pound Sell euro [Member]
Notional Disclosures [Abstract]
Net notional position of foreign currency exchange derivatives \| £			£ 5		£ 4
Sell Canadian dollar, buy U.S. dollar [Member]
Notional Disclosures [Abstract]
Net notional position of foreign currency exchange derivatives	$ 441			$ 1,337
Sell Canadian dollar, buy U.S. dollar [Member] \| Not Designated as Hedging Instrument [Member]
Notional Disclosures [Abstract]
Net notional position of foreign currency exchange derivatives		$ 1,350
Derivative, Currency Bought		USD
Derivative, Currency Sold		CAD
Derivative, Forward Exchange Rate \| $ / $		0.748
Buy CAD, Sell USD [Member] \| Not Designated as Hedging Instrument [Member]
Notional Disclosures [Abstract]
Net notional position of foreign currency exchange derivatives	$ 900
Derivative, Currency Bought	CAD
Derivative, Currency Sold	USD
Derivative, Foreign Currency Option Strike Price \| $ / $	0.718		0.718