Basis Of Presentation And New Accounting Standards (Policies)	9 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis Of Presentation	The accompanying condensed consolidated financial statements include the accounts of Helix Energy Solutions Group, Inc. and its subsidiaries (collectively, Helix). Unless the context indicates otherwise, the terms “we,” “us” and “our” in this report refer collectively to Helix and its subsidiaries. All material intercompany accounts and transactions have been eliminated. These unaudited condensed consolidated financial statements have been prepared pursuant to instructions for the Quarterly Report on Form 10-Q required to be filed with the Securities and Exchange Commission (the “SEC”) and do not include all information and footnotes normally included in annual financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). The accompanying condensed consolidated financial statements have been prepared in conformity with GAAP in U.S. dollars and are consistent in all material respects with those applied in our 2018 Annual Report on Form 10-K (“2018 Form 10-K”) with the exception of the impact of adopting the new lease accounting standard in 2019 (see below). The preparation of these financial statements requires us to make estimates and judgments that affect the amounts reported in the financial statements and the related disclosures. Actual results may differ from our estimates. We have made all adjustments, which, unless otherwise disclosed, are of normal recurring nature, that we believe are necessary for a fair presentation of the condensed consolidated balance sheets, statements of operations, statements of comprehensive income and statements of cash flows, as applicable. The operating results for the three- and nine-month periods ended September 30, 2019 are not necessarily indicative of the results that may be expected for the year ending December 31, 2019. Our balance sheet as of December 31, 2018 included herein has been derived from the audited balance sheet as of December 31, 2018 included in our 2018 Form 10-K. These unaudited condensed consolidated financial statements should be read in conjunction with the annual audited consolidated financial statements and notes thereto included in our 2018 Form 10-K.
Reclassifications	Certain reclassifications were made to previously reported amounts in the consolidated financial statements and notes thereto to make them consistent with the current presentation format.
New Accounting Standards	New accounting standards adopted In February 2016, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) No. 2016-02, “Leases (Topic 842)” (“ASC 842”), which was updated by subsequent amendments. ASC 842 requires a lessee to recognize a lease right-of-use asset and related lease liability for most leases, including those classified as operating leases. ASC 842 also changes the definition of a lease and requires expanded quantitative and qualitative disclosures for both lessees and lessors. We adopted ASC 842 in the first quarter of 2019 using the modified retrospective method. We also elected the package of practical expedients permitted under the transition guidance that, among other things, allows companies to carry forward their historical lease classification. Our adoption of ASC 842 resulted in the recognition of operating lease liabilities of $259.0 million and corresponding right-of-use (“ROU”) assets of $253.4 million (net of existing prepaid/deferred rent balances) as of January 1, 2019. In addition, we reclassified the remaining deferred gain of $4.6 million (net of deferred taxes of $0.9 million) on a 2016 sale and leaseback transaction to retained earnings. Subsequent to adoption, leases in foreign currencies will generate foreign currency gains and losses, and we will no longer amortize the deferred gain from the aforementioned sale and leaseback transaction. Aside from these changes, ASC 842 is not expected to have a material impact on our net earnings or cash flows. New accounting standards issued but not yet effective In June 2016, the FASB issued ASU No. 2016-13, “Measurement of Credit Losses on Financial Instruments,” which was updated by subsequent amendments. This ASU replaces the current incurred loss model for measurement of credit losses on financial assets (including trade receivables) with a forward-looking expected loss model based on historical experience, current conditions, and reasonable and supportable forecasts. The guidance will be effective for us as of January 1, 2020. We are currently evaluating the impact this guidance will have on our consolidated financial statements. We do not expect any other recent accounting standards to have a material impact on our financial position, results of operations or cash flows.