Basis of Presentation, Significant Accounting Policies, and Recently Issued Accounting Standards	3 Months Ended
Mar. 31, 2013
Accounting Policies [Abstract]
Basis of Presentation, Significant Accounting Policies, and Recently Issued Accounting Standards	Note 2 - Basis of Presentation, Significant Accounting Policies, and Recently Issued Accounting Standards Basis of Presentation The accompanying unaudited condensed consolidated financial statements of SM Energy have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information and the instructions to Form 10-Q and Regulation S-X. They do not include all information and notes required by GAAP for complete financial statements. However, except as disclosed herein, there has been no material change in the information disclosed in the notes to consolidated financial statements included in SM Energy’s Annual Report on Form 10-K for the year ended December 31, 2012, (“2012 Form 10-K”). In the opinion of management, all adjustments, consisting of normal recurring accruals considered necessary for a fair presentation of interim financial information, have been included. Operating results for the periods presented are not necessarily indicative of expected results for the full year. In connection with the preparation of its unaudited condensed consolidated financial statements, the Company evaluated events subsequent to the balance sheet date of March 31, 2013, through the filing date of this report. Other Significant Accounting Policies The accounting policies followed by the Company are set forth in Note 1 to the Company’s consolidated financial statements in the 2012 Form 10-K, and are supplemented throughout the notes to the unaudited condensed consolidated financial statements in this report. It is suggested that these unaudited condensed consolidated financial statements be read in conjunction with the consolidated financial statements and notes included in the 2012 Form 10-K. Recently Issued and Adopted Accounting Standards On January 1, 2013, the Company adopted new authoritative accounting guidance issued by the Financial Accounting Standards Board (“FASB”), which applied to the offsetting of certain assets and liabilities on the balance sheet and clarified the application of previously issued guidance to derivative instruments, repurchase agreements, and securities lending transactions, requiring disclosure of gross and net amounts for those items. The only item applicable to the Company is derivative instruments. The Company currently records its derivative instruments on a gross basis by contract; therefore, the adoption of this statement did not have a material impact on the Company’s financial statements or disclosures. On March 31, 2013, the Company adopted the presentation requirements of new authoritative accounting guidance issued by the FASB in February 2013. The purpose of the guidance was to improve the reporting of reclassifications out of accumulated other comprehensive income (loss) (“AOCIL”), which required entities to report the effect of significant reclassifications out of AOCIL into current year income on the respective line items in net income. The presentation of those amounts may be on the face of the financial statements or in the notes thereto. This amendment was effective prospectively for periods beginning after December 15, 2012. As of March 31, 2013, the Company does not have any significant reclassifications out of AOCIL into current year income. The Company will continue to monitor items that are subject to the new guidance and elect the presentation for significant items reclassified out of AOCIL, for the disclosure period any such item becomes material. In February 2013, the FASB issued new authoritative accounting guidance related to the recognition and measurement of obligations arising from joint and several liability arrangements. This authoritative accounting guidance is effective for interim and annual periods beginning after December 15, 2013. The Company is currently evaluating the provisions of this authoritative accounting guidance and assessing its impact, but does not currently believe it will have a material effect on the Company’s financial statements or disclosures. There are no new significant accounting standards applicable to the Company that have been issued but not yet adopted by the Company as of March 31, 2013.

Note 2 - Basis of Presentation, Significant Accounting Policies, and Recently Issued Accounting Standards

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements of SM Energy have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information and the instructions to Form 10-Q and Regulation S-X. They do not include all information and notes required by GAAP for complete financial statements. However, except as disclosed herein, there has been no material change in the information disclosed in the notes to consolidated financial statements included in SM Energy’s Annual Report on Form 10-K for the year ended December 31, 2012, (“2012 Form 10-K”). In the opinion of management, all adjustments, consisting of normal recurring accruals considered necessary for a fair presentation of interim financial information, have been included. Operating results for the periods presented are not necessarily indicative of expected results for the full year. In connection with the preparation of its unaudited condensed consolidated financial statements, the Company evaluated events subsequent to the balance sheet date of March 31, 2013, through the filing date of this report.

Other Significant Accounting Policies

The accounting policies followed by the Company are set forth in Note 1 to the Company’s consolidated financial statements in the 2012 Form 10-K, and are supplemented throughout the notes to the unaudited condensed consolidated financial statements in this report. It is suggested that these unaudited condensed consolidated financial statements be read in conjunction with the consolidated financial statements and notes included in the 2012 Form 10-K.

Recently Issued and Adopted Accounting Standards

On January 1, 2013, the Company adopted new authoritative accounting guidance issued by the Financial Accounting Standards Board (“FASB”), which applied to the offsetting of certain assets and liabilities on the balance sheet and clarified the application of previously issued guidance to derivative instruments, repurchase agreements, and securities lending transactions, requiring disclosure of gross and net amounts for those items. The only item applicable to the Company is derivative instruments. The Company currently records its derivative instruments on a gross basis by contract; therefore, the adoption of this statement did not have a material impact on the Company’s financial statements or disclosures.

On March 31, 2013, the Company adopted the presentation requirements of new authoritative accounting guidance issued by the FASB in February 2013. The purpose of the guidance was to improve the reporting of reclassifications out of accumulated other comprehensive income (loss) (“AOCIL”), which required entities to report the effect of significant reclassifications out of AOCIL into current year income on the respective line items in net income. The presentation of those amounts may be on the face of the financial statements or in the notes thereto. This amendment was effective prospectively for periods beginning after December 15, 2012. As of March 31, 2013, the Company does not have any significant reclassifications out of AOCIL into current year income. The Company will continue to monitor items that are subject to the new guidance and elect the presentation for significant items reclassified out of AOCIL, for the disclosure period any such item becomes material.

In February 2013, the FASB issued new authoritative accounting guidance related to the recognition and measurement of obligations arising from joint and several liability arrangements. This authoritative accounting guidance is effective for interim and annual periods beginning after December 15, 2013. The Company is currently evaluating the provisions of this authoritative accounting guidance and assessing its impact, but does not currently believe it will have a material effect on the Company’s financial statements or disclosures.

There are no new significant accounting standards applicable to the Company that have been issued but not yet adopted by the Company as of March 31, 2013.