Supplementary Information - Condensed Consolidating Financial Information Balance Sheet (Details Textual) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Inercompany Distribution of Earnings	$ 605	$ 398	$ 876
Repayment of Debt	7,876	2,251	103
ConocoPhillips Company [Member] \| Return Of Capital from Consolidated Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Return of Capital	7,800
Reportable Legal Entities [Member] \| ConocoPhillips [Member] \| Return Of Capital from Consolidated Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Return of Capital	7,800	2,300	3,500
Intercompany Dividend Paid	200
Reportable Legal Entities [Member] \| ConocoPhillips Company [Member]
Condensed Financial Statements, Captions [Line Items]
Intercompany other liabilities	(1,400)
Repayment of Debt	4,411	164	100
Reportable Legal Entities [Member] \| ConocoPhillips Company [Member] \| Return Of Capital from Consolidated Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Return of Capital	9,800
Intercompany other liabilities	8,000	2,300	3,500
Reportable Legal Entities [Member] \| ConocoPhillips Canada Funding Company I [Member]
Condensed Financial Statements, Captions [Line Items]
Repayment of Debt	0	1,250	0
Reportable Legal Entities [Member] \| All other nonguarantor subsidiaries of ConocoPhillips.
Condensed Financial Statements, Captions [Line Items]
Intercompany other liabilities	1,400
Repayment of Debt	2,272	$ 2,492	$ 103
Reportable Legal Entities [Member] \| All other nonguarantor subsidiaries of ConocoPhillips. \| Return Of Capital from Consolidated Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Intercompany other liabilities	$ 9,800

Return of capital relieving intercompany liability.

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Dividend from ConocoPhillips Company to ConocoPhillips to settle certain accumulated intercompany balances. No impact to consolidated financial statements.

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Amount of distribution received from equity method investee for return on investment, classified as operating activities. Excludes distribution for return of investment, classified as investing activities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(10))
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(12))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 21D
-URI http://asc.fasb.org/extlink&oid=98514028&loc=SL94080555-108585

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Amount of distribution received from equity method investee for return of investment, classified as investing activities. Excludes distribution for return on investment, classified as operating activities.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 21D
-URI http://asc.fasb.org/extlink&oid=98514028&loc=SL94080555-108585

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The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

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