Assets Held for Sale or Sold	9 Months Ended
Sep. 30, 2018
Disposal Group Excluding Discontinued Operation Additional Disclosures [Abstract]
Disposal Groups Exluding Discontinued Operations Disclosure [TextBlock]	Note 5—Assets Held for Sale, Dispositions, Acquisitions and Other Planned Transactions Assets Held for Sale and Other Planned Acquisitions In the second quarter of 2017, we signed a definitive agreement to sell our interests in the Barnett, and the assets met the asset held for sale criteria. As of September 30, 2017, we had recorded before-tax impairments of $568 million to reduce our carrying value of these assets to fair value. The agreement was terminated in the fourth quarter of 2017, and we continued to market the asset in 2018. In the first quarter of 2018, we recorded a before-tax impairment of $44 million to reduce the net carrying value to fair value of $250 million based on information gathered during marketing efforts. Marketing efforts ceased in April 2018, and the assets were reclassified as held for use in the second quarter of 2018. In the third quarter of 2018, we signed a definitive agreement to sell our interest in the Barnett to Lime Rock Resources for approximately $230 million, subject to customary adjustments. The transaction is expected to close by year-end 2018. In the third quarter of 2018, we recorded a before-tax impairment of $43 million to reduce the carrying value to fair value less costs to sell. As of September 30, 2018, our Barnett asset had a net carrying value of $201 million and was considered held for sale resulting in the reclassification of $250 million of PP&E to “Prepaid expenses and other current assets” and $49 million of noncurrent liabilities, primarily ARO, to “Other accruals” on our consolidated balance sheet. The before-tax loss associated with our interests in the Barnett, including the impairments noted above, was $59 million and $575 million for the nine-month periods of 2018 and 2017, respectively. The Barnett results of operations are reported in our Lower 48 segment. In July 2018, we entered into an agreement to sell a ConocoPhillips subsidiary to BP. The subsidiary will hold a 16.5 percent interest in the BP-operated Clair Field in the United Kingdom and we will retain a 7.5 percent interest in the field. At the same time, we entered into an agreement with BP to acquire their 39.2 percent nonoperated interest in the Greater Kuparuk Area in Alaska, including their 38 percent interest in the Kuparuk Transportation Company (Kuparuk Assets). Both transactions are subject to regulatory approvals and are expected to close simultaneously in late 2018. Excluding customary adjustments, the transactions are expected to be cash neutral. Depending on the timing of regulatory approvals, we anticipate recognizing a noncash gain between $0.5 billion to $1.0 billion on completion of the sale of the ConocoPhillips subsidiary holding 16.5 percent of the Clair Field, after customary adjustments and foreign exchange impacts. As of September 30, 2018, our 16.5 percent interest in the Clair Field had a net carrying value of approximately $945 million consisting primarily of $1.552 billion of PP&E, $544 million of deferred tax liabilities, and $63 million of ARO. As of September 30, 2018, our 16.5 percent interest in the Clair Field was considered held for sale resulting in the reclassification of the $1.552 billion of PP&E to “Prepaid expenses and other current assets” and $63 million of ARO to “Other accruals” on our consolidated balance sheet. The before-tax earnings associated with our 16.5 percent interest in the Clair Field was $13 million and $1 million for the nine months ended September 30, 2018 and 2017, respectively. Results of operations for our interest in the Clair Field are reported within our Europe and North Africa segment and the Kuparuk Assets are included in our Alaska segment. Asset Dispositions In the first quarter of 2018, we completed the sale of certain properties in the Lower 48 segment for net proceeds of $112 million. No gain or loss was recognized on the sale. In the second quarter of 2018, we completed the sale of a package of largely undeveloped acreage in the Lower 48 segment for net proceeds of $105 million. No gain or loss was recognized on the sale. In September 2018, we completed a noncash exchange of undeveloped acreage in the Lower 48 segment. The transaction was recorded at fair value resulting in the recognition of a $56 million before-tax gain which is reflected as “Gain on dispositions” in our consolidated income statement. In the first nine months of 2018, we completed several other dispositions. In the second quarter of 2017, we completed the sale of our 50 percent nonoperated interest in the Foster Creek Christina Lake (FCCL) Partnership, as well as the majority of our western Canada gas assets to Cenovus Energy. Consideration for the transaction included a five-year uncapped contingent payment. The contingent payment, calculated on a quarterly basis, is $6 million Canadian dollars (CAD) for every $1 CAD by which the Western Canada Select quarterly average crude price exceeds $52 CAD per barrel. Contingent payments received during the five-year period will be reflected as “Gain on dispositions” in our consolidated income statement. In 2018, we recorded gains on dispositions for these contingent payments of $50 million in the second quarter and $45 million in the third quarter. In the third quarter of 2017, we completed the sale of our interests in the San Juan Basin to an affiliate of Hilcorp Energy Company for $2.5 billion in cash after customary adjustments and recognized a loss on disposition of $22 million. The transaction includes a contingent payment of up to $300 million. The six-year contingent payment is effective beginning January 1, 2018, and is due annually for the periods in which the monthly U.S. Henry Hub price is at or above $3.20 per million British thermal units. The San Juan Basin results of operations were reported within our Lower 48 segment. Acquisition In the second quarter of 2018, we obtained regulatory approvals for the agreement with Anadarko Petroleum Corporation to acquire its 22 percent nonoperated interest in the Western North Slope of Alaska, as well as its interest in the Alpine Pipeline. The transaction was completed in May 2018 for $386 million, after customary adjustments. These assets are included in our Alaska segment. Other Planned Disposition On October 1, 2018, we entered into an agreement to sell our 30 percent interest in Greater Sunrise Fields to the government of Timor-Leste for $350 million, subject to customary adjustments. The transaction is conditional on the funding approval from the Timor-Leste Council of Ministers and National Parliament, as well as regulatory approvals and partner pre-emption rights. We expect it to close in early 2019. These assets are included in our Asia Pacific and Middle East segment.

Note 5—Assets Held for Sale, Dispositions, Acquisitions and Other Planned Transactions

Assets Held for Sale and Other Planned Acquisitions

In the second quarter of 2017, we signed a definitive agreement to sell our interests in the Barnett, and the assets met the asset held for sale criteria. As of September 30, 2017, we had recorded before-tax impairments of $568 million to reduce our carrying value of these assets to fair value. The agreement was terminated in the fourth quarter of 2017, and we continued to market the asset in 2018. In the first quarter of 2018, we recorded a before-tax impairment of $44 million to reduce the net carrying value to fair value of $250 million based on information gathered during marketing efforts. Marketing efforts ceased in April 2018, and the assets were reclassified as held for use in the second quarter of 2018. In the third quarter of 2018, we signed a definitive agreement to sell our interest in the Barnett to Lime Rock Resources for approximately $230 million, subject to customary adjustments. The transaction is expected to close by year-end 2018. In the third quarter of 2018, we recorded a before-tax impairment of $43 million to reduce the carrying value to fair value less costs to sell. As of September 30, 2018, our Barnett asset had a net carrying value of $201 million and was considered held for sale resulting in the reclassification of $250 million of PP&E to “Prepaid expenses and other current assets” and $49 million of noncurrent liabilities, primarily ARO, to “Other accruals” on our consolidated balance sheet. The before-tax loss associated with our interests in the Barnett, including the impairments noted above, was $59 million and $575 million for the nine-month periods of 2018 and 2017, respectively. The Barnett results of operations are reported in our Lower 48 segment.

In July 2018, we entered into an agreement to sell a ConocoPhillips subsidiary to BP. The subsidiary will hold a 16.5 percent interest in the BP-operated Clair Field in the United Kingdom and we will retain a 7.5 percent interest in the field. At the same time, we entered into an agreement with BP to acquire their 39.2 percent nonoperated interest in the Greater Kuparuk Area in Alaska, including their 38 percent interest in the Kuparuk Transportation Company (Kuparuk Assets). Both transactions are subject to regulatory approvals and are expected to close simultaneously in late 2018. Excluding customary adjustments, the transactions are expected to be cash neutral. Depending on the timing of regulatory approvals, we anticipate recognizing a noncash gain between $0.5 billion to $1.0 billion on completion of the sale of the ConocoPhillips subsidiary holding 16.5 percent of the Clair Field, after customary adjustments and foreign exchange impacts. As of September 30, 2018, our 16.5 percent interest in the Clair Field had a net carrying value of approximately $945 million consisting primarily of $1.552 billion of PP&E, $544 million of deferred tax liabilities, and $63 million of ARO. As of September 30, 2018, our 16.5 percent interest in the Clair Field was considered held for sale resulting in the reclassification of the $1.552 billion of PP&E to “Prepaid expenses and other current assets” and $63 million of ARO to “Other accruals” on our consolidated balance sheet. The before-tax earnings associated with our 16.5 percent interest in the Clair Field was $13 million and $1 million for the nine months ended September 30, 2018 and 2017, respectively. Results of operations for our interest in the Clair Field are reported within our Europe and North Africa segment and the Kuparuk Assets are included in our Alaska segment.

Asset Dispositions

In the first quarter of 2018, we completed the sale of certain properties in the Lower 48 segment for net proceeds of $112 million. No gain or loss was recognized on the sale. In the second quarter of 2018, we completed the sale of a package of largely undeveloped acreage in the Lower 48 segment for net proceeds of $105 million. No gain or loss was recognized on the sale. In September 2018, we completed a noncash exchange of undeveloped acreage in the Lower 48 segment. The transaction was recorded at fair value resulting in the recognition of a $56 million before-tax gain which is reflected as “Gain on dispositions” in our consolidated income statement. In the first nine months of 2018, we completed several other dispositions.

In the second quarter of 2017, we completed the sale of our 50 percent nonoperated interest in the Foster Creek Christina Lake (FCCL) Partnership, as well as the majority of our western Canada gas assets to Cenovus Energy. Consideration for the transaction included a five-year uncapped contingent payment. The contingent payment, calculated on a quarterly basis, is $6 million Canadian dollars (CAD) for every $1 CAD by which the Western Canada Select quarterly average crude price exceeds $52 CAD per barrel. Contingent payments received during the five-year period will be reflected as “Gain on dispositions” in our consolidated income statement. In 2018, we recorded gains on dispositions for these contingent payments of $50 million in the second quarter and $45 million in the third quarter.

In the third quarter of 2017, we completed the sale of our interests in the San Juan Basin to an affiliate of Hilcorp Energy Company for $2.5 billion in cash after customary adjustments and recognized a loss on disposition of $22 million. The transaction includes a contingent payment of up to $300 million. The six-year contingent payment is effective beginning January 1, 2018, and is due annually for the periods in which the monthly U.S. Henry Hub price is at or above $3.20 per million British thermal units. The San Juan Basin results of operations were reported within our Lower 48 segment.

Acquisition

In the second quarter of 2018, we obtained regulatory approvals for the agreement with Anadarko Petroleum Corporation to acquire its 22 percent nonoperated interest in the Western North Slope of Alaska, as well as its interest in the Alpine Pipeline. The transaction was completed in May 2018 for $386 million, after customary adjustments. These assets are included in our Alaska segment.

Other Planned Disposition

On October 1, 2018, we entered into an agreement to sell our 30 percent interest in Greater Sunrise Fields to the government of Timor-Leste for $350 million, subject to customary adjustments. The transaction is conditional on the funding approval from the Timor-Leste Council of Ministers and National Parliament, as well as regulatory approvals and partner pre-emption rights. We expect it to close in early 2019. These assets are included in our Asia Pacific and Middle East segment.