Reduction to previous award.

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Revised amount awarded from other party in judgment or settlement of litigation.

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The duration from whence interests were sold.

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Total costs accrued as of the balance sheet date for environmental loss contingencies.

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

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The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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Amount awarded from other party in judgment or settlement of litigation.

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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.

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The total number of new claims filed pertaining to a loss contingency during the period.

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Description of the terms of a settlement agreement which resolved the legal matter, including the nature of the consideration, timing of payment, and the nature of rights obtained or lost (for example, but not limited to, patent, trademark, copyright, license and franchise rights).

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Cash received for the settlement of litigation during the current period.

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Contingencies and Commitments - Textual (Details) $ in Millions	1 Months Ended			3 Months Ended	12 Months Ended	32 Months Ended
	Mar. 31, 2019 USD ($)	Aug. 31, 2018 USD ($)	Apr. 30, 2018 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2017 Lawsuits	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Aug. 29, 2019 USD ($)	Aug. 02, 2019 USD ($)
Loss Contingencies [Line Items]
Letters of Credit Outstanding, Amount				$ 309		$ 309
Several Louisiana parishes and the State of Louisiana against oil and gas companies [Member]
Loss Contingencies [Line Items]
Loss Contingency, New Claims Filed, Number \| Lawsuits					43
Several Louisiana parishes and the State of Louisiana against oil and gas companies [Member] \| ConocoPhillips Entities [Member]
Loss Contingencies [Line Items]
Loss Contingency, New Claims Filed, Number \| Lawsuits					22
Outer Continental Shelf Lease [Member] \| Phillips Petroleum Company [Member]
Loss Contingencies [Line Items]
Ownership percentage in equity investment				25.00%		25.00%
Sale Of Interest, Duration				30 years
Venezuela \| Conoco Phillips Vs Petroleos de Venezuela SA (ICSID) [Member]
Loss Contingencies [Line Items]
Litigation Settlement, Amount Awarded from Other Party	$ 8,700
Litigation Award Reduction								$ 227
Litigation Settlement Amount Awarded From Other Party Revised				$ 8,500		$ 8,500
Venezuela \| ConocoPhillips Versus Petroleos De Venezuela 2 [Member]
Loss Contingencies [Line Items]
Litigation Settlement, Amount Awarded from Other Party		$ 500	$ 2,000
Loss Contingency, Settlement Agreement, Terms				In August 2018, ConocoPhillips entered into a settlement with PDVSA to recover the full amount of this ICC award, plus interest through the payment period, including initial payments totaling approximately $500 million within a period of 90 days from the time of signing of the settlement agreement. The balance of the settlement is to be paid quarterly over a period of four and a half years. To date, ConocoPhillips has received approximately $754 million. Per the settlement, PDVSA recognized the ICC award as a judgment in various jurisdictions, and ConocoPhillips agreed to suspend its legal enforcement actions. ConocoPhillips sent notices of default to PDVSA on October 14 and November 12, 2019, and to date PDVSA failed to cure its breach.
Litigation Settlement Amount Awarded From Other Party Revised									$ 33
Cash Proceeds from Legal Settlements						754
United States And Canada [Member]
Loss Contingencies [Line Items]
Total environmental accrual included in balance sheet				$ 188		$ 188	$ 180
Cleanup Remediation Activities [Member] \| United States And Canada [Member]
Loss Contingencies [Line Items]
Loss Contingency, Settlement Agreement, Terms				We expect to incur a substantial amount of these expenditures within the next 30 years.