General (Policies)	9 Months Ended
Sep. 30, 2019
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The unaudited consolidated financial statements have been prepared in conformity with United States Generally Accepted Accounting Principles (GAAP) and include the accounts of OPC, its subsidiaries, VIEs for which Occidental is the primary beneficiary, and its undivided interests in oil and gas exploration and production ventures. Occidental has made its disclosures in accordance with GAAP as they apply to interim reporting, and condensed or omitted, as permitted by the Securities and Exchange Commission's rules and regulations, certain information and disclosures normally included in consolidated financial statements and notes. These unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto in Occidental's Annual Report on Form 10-K for the year ended December 31, 2018 (the 2018 Form 10-K). The Merger, including the addition of WES Midstream as a new reporting segment, introduced different revenue and expense streams to Occidental's legacy operations. As a result, changes were made to the structure of certain financial statements, notes and supplementary data to provide clarity and to conform to the current presentation.
Variable Interest Entities	Variable Interest Entities Occidental, through its ownership of the general partner interest in WES, has the power to direct the activities that significantly affect the economic performance of WES and the obligation to absorb losses or the right to receive benefits that could be significant to WES; therefore, Occidental is considered the primary beneficiary and consolidates WES and all of its consolidated subsidiaries. WES maintains its own capital structure that is separate from Occidental, consisting of its own debt instruments and publicly traded common units. All intercompany transactions have been eliminated. The assets of WES and its subsidiaries cannot be used by Occidental for general corporate purposes and are included in and disclosed parenthetically on Occidental's consolidated condensed balance sheets, if material. The carrying amount of liabilities related to WES for which the creditors do not have recourse to Occidental's assets are also included in and disclosed parenthetically on Occidental's Consolidated Condensed Balance Sheets, if material. All outstanding debt for WES at September 30, 2019, including any borrowings under the WES revolving credit facility (WES RCF) and WES Term Loan Facility, is recourse to the general partner of Western Midstream Operating, LP (WES Operating), which in turn has been indemnified in certain circumstances by certain indirect wholly owned subsidiaries of Occidental for such liabilities. See Note 9 - Long-Term Debt. WES's sources of liquidity include cash and cash equivalents, cash flows generated from operations, interest income from a note receivable from Anadarko, borrowings under the WES RCF, the issuance of additional partnership units, and debt offerings.
Discontinued Operations	Discontinued Operations In connection with the Merger, Occidental agreed to sell to TOTAL S.A. (Total) all of the assets, liabilities, businesses, and operations of Anadarko's operations in Algeria, Ghana, Mozambique and South Africa (collectively, the Africa Assets) for $8.8 billion, subject to certain purchase price adjustments. In August 2019, a purchase and sale agreement was executed for these Africa Assets. This transaction is conditioned on the receipt of required regulatory approvals, as well as other customary closing conditions. On September 27, 2019, Occidental completed the sale of Anadarko’s Mozambique LNG assets to Total for $4.2 billion. The assets and liabilities for Algeria, Ghana and South Africa, are presented as held for sale at September 30, 2019. The results of operations of the Africa Assets are presented as discontinued operations, see Note 4 - Acquisitions, Dispositions, and Other. Unless otherwise indicated, information presented in the Notes to the Consolidated Condensed Financial Statements relates only to Occidental's continuing operations. Information related to discontinued operations is included in Note 4 - Acquisitions, Dispositions, and Other, and in some instances, where appropriate, is included as a separate disclosure within the individual Notes to the Consolidated Condensed Financial Statements.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill resulting from the Merger was assigned to WES Midstream and represents the excess of the purchase price over the estimated fair value of the assets acquired and liabilities assumed. Goodwill is subject to annual impairment testing. Changes in goodwill may result from, among other things, finalization of preliminary purchase price allocations, impairments, additional acquisitions, or divestitures. See Note 3 - The Merger. Other intangible assets represent contractual rights obtained in connection with the Merger that had favorable contractual terms relative to market terms as well as customer-related intangible assets, including customer relationships. Other intangible assets are amortized over their estimated useful lives and are assessed for impairment with the associated long-lived asset group whenever impairment indicators are present. See Note 3 - The Merger.
Accounting and Disclosure Changes	Accounting and Disclosure Changes In January 2019, Occidental adopted the new lease standard Accounting Standards Codification Topic 842 - Leases (ASC 842). The new standard requires Occidental to recognize most leases, including operating leases, on the balance sheet. The new rules require lessees to recognize a right-of-use asset (ROU) and lease liability for all leases with lease terms of more than 12 months. Occidental adopted the standard using the modified retrospective approach, including adopting several optional practical expedients. See Note 10 - Lease Commitments.

General (Policies)

9 Months Ended

Sep. 30, 2019

The unaudited consolidated financial statements have been prepared in conformity with United States Generally Accepted Accounting Principles (GAAP) and include the accounts of OPC, its subsidiaries, VIEs for which Occidental is the primary beneficiary, and its undivided interests in oil and gas exploration and production ventures. Occidental has made its disclosures in accordance with GAAP as they apply to interim reporting, and condensed or omitted, as permitted by the Securities and Exchange Commission's rules and regulations, certain information and disclosures normally included in consolidated financial statements and notes. These unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto in Occidental's Annual Report on Form 10-K for the year ended December 31, 2018 (the 2018 Form 10-K).

The Merger, including the addition of WES Midstream as a new reporting segment, introduced different revenue and expense streams to Occidental's legacy operations. As a result, changes were made to the structure of certain financial statements, notes and supplementary data to provide clarity and to conform to the current presentation.

Variable Interest Entities

Occidental, through its ownership of the general partner interest in WES, has the power to direct the activities that significantly affect the economic performance of WES and the obligation to absorb losses or the right to receive benefits that could be significant to WES; therefore, Occidental is considered the primary beneficiary and consolidates WES and all of its consolidated subsidiaries. WES maintains its own capital structure that is separate from Occidental, consisting of its own debt instruments and publicly traded common units. All intercompany transactions have been eliminated.

The assets of WES and its subsidiaries cannot be used by Occidental for general corporate purposes and are included in and disclosed parenthetically on Occidental's consolidated condensed balance sheets, if material. The carrying amount of liabilities related to WES for which the creditors do not have recourse to Occidental's assets are also included in and disclosed parenthetically on Occidental's Consolidated Condensed Balance Sheets, if material.

All outstanding debt for WES at September 30, 2019, including any borrowings under the WES revolving credit facility (WES RCF) and WES Term Loan Facility, is recourse to the general partner of Western Midstream Operating, LP (WES Operating), which in turn has been indemnified in certain circumstances by certain indirect wholly owned subsidiaries of Occidental for such liabilities. See Note 9 - Long-Term Debt.

WES's sources of liquidity include cash and cash equivalents, cash flows generated from operations, interest income from a note receivable from Anadarko, borrowings under the WES RCF, the issuance of additional partnership units, and debt offerings.

Discontinued Operations

In connection with the Merger, Occidental agreed to sell to TOTAL S.A. (Total) all of the assets, liabilities, businesses, and operations of Anadarko's operations in Algeria, Ghana, Mozambique and South Africa (collectively, the Africa Assets) for $8.8 billion, subject to certain purchase price adjustments. In August 2019, a purchase and sale agreement was executed for these Africa Assets. This transaction is conditioned on the receipt of required regulatory approvals, as well as other customary closing conditions. On September 27, 2019, Occidental completed the sale of Anadarko’s Mozambique LNG assets to Total for $4.2 billion. The assets and liabilities for Algeria, Ghana and South Africa, are presented as held for sale at September 30, 2019. The results of operations of the Africa Assets are presented as discontinued operations, see Note 4 - Acquisitions, Dispositions, and Other.

Unless otherwise indicated, information presented in the Notes to the Consolidated Condensed Financial Statements relates only to Occidental's continuing operations. Information related to discontinued operations is included in Note 4 - Acquisitions, Dispositions, and Other, and in some instances, where appropriate, is included as a separate disclosure within the individual Notes to the Consolidated Condensed Financial Statements.

Goodwill and Other Intangible Assets

Goodwill resulting from the Merger was assigned to WES Midstream and represents the excess of the purchase price over the estimated fair value of the assets acquired and liabilities assumed. Goodwill is subject to annual impairment testing. Changes in goodwill may result from, among other things, finalization of preliminary purchase price allocations, impairments, additional acquisitions, or divestitures. See Note 3 - The Merger.

Other intangible assets represent contractual rights obtained in connection with the Merger that had favorable contractual terms relative to market terms as well as customer-related intangible assets, including customer relationships. Other intangible assets are amortized over their estimated useful lives and are assessed for impairment with the associated long-lived asset group whenever impairment indicators are present. See Note 3 - The Merger.

Accounting and Disclosure Changes

In January 2019, Occidental adopted the new lease standard Accounting Standards Codification Topic 842 - Leases (ASC 842). The new standard requires Occidental to recognize most leases, including operating leases, on the balance sheet. The new rules require lessees to recognize a right-of-use asset (ROU) and lease liability for all leases with lease terms of more than 12 months. Occidental adopted the standard using the modified retrospective approach, including adopting several optional practical expedients. See Note 10 - Lease Commitments.