Basis of Presentation (Notes)	9 Months Ended
Sep. 30, 2017
Basis of Presentation [Abstract]
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	Basis of Presentation These consolidated financial statements are unaudited; however, in the opinion of management, these statements reflect all adjustments necessary for a fair statement of the results for the periods reported. All such adjustments are of a normal recurring nature unless disclosed otherwise. These consolidated financial statements, including notes, have been prepared in accordance with the applicable rules of the SEC and do not include all of the information and disclosures required by U.S. GAAP for complete financial statements. These interim financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in our 2016 Annual Report on Form 10-K. The results of operations for the third quarter and first nine months of 2017 are not necessarily indicative of the results to be expected for the full year. As a result of the announcement to divest of our Canadian business in the first quarter 2017 and its subsequent closing in the second quarter of 2017, we have reflected this business as discontinued operations in all periods presented. Assets and liabilities are presented as held for sale in the historical periods in the consolidated balance sheets. The disclosures in this report related to the results of operations and cash flows are presented on the basis of continuing operations, unless otherwise noted. The characteristics and composition of our North America E&P reporting segment remained unchanged and there was no effect on previously reported segment information. As all our remaining properties within the segment are located within the United States, we concluded that our North America E&P segment would be renamed United States E&P segment, effective June 30, 2017. During the first nine months, no changes occurred to our International E&P segment. See Note 6 for discussion of the divestiture in further detail and Note 7 for further information on our reportable segments. During the first quarter of 2017, we adopted the accounting standards update issued by the FASB in March 2016 pertaining to share-based payment transactions. As a result of this adoption, all cash payments for withheld shares made to taxing authorities on the employees' behalf will be presented within the financing activities section instead of the operating activities section of the statement of cash flows. We have elected the retrospective method for adoption of this update and the change in the statement of cash flows is not material for nine months ended September 30, 2016. Excess tax benefits will be classified as an operating activity within the statement of cash flows on a prospective basis; as such, prior periods were not adjusted. See Note 2 for additional discussion.

Basis of Presentation

These consolidated financial statements are unaudited; however, in the opinion of management, these statements reflect all adjustments necessary for a fair statement of the results for the periods reported. All such adjustments are of a normal recurring nature unless disclosed otherwise. These consolidated financial statements, including notes, have been prepared in accordance with the applicable rules of the SEC and do not include all of the information and disclosures required by U.S. GAAP for complete financial statements.

These interim financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in our 2016 Annual Report on Form 10-K. The results of operations for the third quarter and first nine months of 2017 are not necessarily indicative of the results to be expected for the full year.

As a result of the announcement to divest of our Canadian business in the first quarter 2017 and its subsequent closing in the second quarter of 2017, we have reflected this business as discontinued operations in all periods presented. Assets and liabilities are presented as held for sale in the historical periods in the consolidated balance sheets. The disclosures in this report related to the results of operations and cash flows are presented on the basis of continuing operations, unless otherwise noted. The characteristics and composition of our North America E&P reporting segment remained unchanged and there was no effect on previously reported segment information. As all our remaining properties within the segment are located within the United States, we concluded that our North America E&P segment would be renamed United States E&P segment, effective June 30, 2017. During the first nine months, no changes occurred to our International E&P segment. See Note 6 for discussion of the divestiture in further detail and Note 7 for further information on our reportable segments.

During the first quarter of 2017, we adopted the accounting standards update issued by the FASB in March 2016 pertaining to share-based payment transactions. As a result of this adoption, all cash payments for withheld shares made to taxing authorities on the employees' behalf will be presented within the financing activities section instead of the operating activities section of the statement of cash flows. We have elected the retrospective method for adoption of this update and the change in the statement of cash flows is not material for nine months ended September 30, 2016. Excess tax benefits will be classified as an operating activity within the statement of cash flows on a prospective basis; as such, prior periods were not adjusted. See Note 2 for additional discussion.