DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION Policies (Policies)	6 Months Ended
Jun. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Principles of Consolidation	Principles of Consolidation The condensed consolidated financial statements include the accounts of Groupon, Inc. and its wholly-owned subsidiaries, majority-owned subsidiaries over which we exercise control and variable interest entities for which we are the primary beneficiary. All intercompany accounts and transactions have been eliminated in consolidation. Outside stockholders' interests in subsidiaries are shown on the condensed consolidated financial statements as Noncontrolling interests.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. generally accepted accounting principles ("GAAP") requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Estimates in our financial statements include, but are not limited to, the following: variable consideration from unredeemed vouchers, income taxes, leases, initial valuation and subsequent impairment testing of goodwill, other intangible assets and long-lived assets, investments, receivables, customer refunds and other reserves, contingent liabilities, and the useful lives of property, equipment and software and intangible assets. Actual results could differ materially from those estimates.
Adoption of New Accounting Standards	Adoption of New Accounting Standards We adopted the guidance in ASU 2016-13, Financial Instruments - Credit Losses (Topic 326) - Measurement of Credit Losses of Financial Instruments ("CECL") on January 1, 2020. This ASU requires entities to measure credit losses for financial assets measured at amortized cost based on expected losses over the lifetime of the asset rather than incurred losses. The adoption of ASU 2016-13 did not have a material impact on the condensed consolidated financial statements. See Note 8, Revenue Recognition, for additional information. We adopted the guidance in ASU 2017-04, Intangibles - Goodwill and Other (Topic 350) - Simplifying the Test for Goodwill Impairment on January 1, 2020. This ASU eliminates Step 2 of the goodwill impairment test and requires a goodwill impairment to be measured as the amount by which a reporting unit's carrying amount exceeds its fair value, not to exceed the carrying amount of its goodwill. During the first quarter 2020, we determined a triggering event occurred that required us to evaluate our goodwill for impairment, and we recorded an impairment charge as a result of that assessment. See Note 2, Goodwill and Long-Lived Assets, for additional information. We adopted the guidance in ASU 2018-13, Fair Value Measurement (Topic 820) - Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement on January 1, 2020. This ASU modifies the disclosure requirements in Topic 820, Fair Value Measurements, by removing, modifying, or adding certain disclosures. The adoption of ASU 2018-13 did not have a material impact on the condensed consolidated financial statements.

DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION Policies (Policies)

6 Months Ended

Jun. 30, 2020

Organization, Consolidation and Presentation of Financial Statements [Abstract]

The condensed consolidated financial statements include the accounts of Groupon, Inc. and its wholly-owned subsidiaries, majority-owned subsidiaries over which we exercise control and variable interest entities for which we are the primary beneficiary. All intercompany accounts and transactions have been eliminated in consolidation. Outside stockholders' interests in subsidiaries are shown on the condensed consolidated financial statements as Noncontrolling interests.

Use of Estimates

The preparation of financial statements in conformity with U.S. generally accepted accounting principles ("GAAP") requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Estimates in our financial statements include, but are not limited to, the following: variable consideration from unredeemed vouchers, income taxes, leases, initial valuation and subsequent impairment testing of goodwill, other intangible assets and long-lived assets, investments, receivables, customer refunds and other reserves, contingent liabilities, and the useful lives of property, equipment and software and intangible assets. Actual results could differ materially from those estimates.

Adoption of New Accounting Standards

We adopted the guidance in ASU 2016-13, Financial Instruments - Credit Losses (Topic 326) - Measurement of Credit Losses of Financial Instruments ("CECL") on January 1, 2020. This ASU requires entities to measure credit losses for financial assets measured at amortized cost based on expected losses over the lifetime of the asset rather than incurred losses. The adoption of ASU 2016-13 did not have a material impact on the condensed consolidated financial statements. See Note 8, Revenue Recognition, for additional information.

We adopted the guidance in ASU 2017-04, Intangibles - Goodwill and Other (Topic 350) - Simplifying the Test for Goodwill Impairment on January 1, 2020. This ASU eliminates Step 2 of the goodwill impairment test and requires a goodwill impairment to be measured as the amount by which a reporting unit's carrying amount exceeds its fair value, not to exceed the carrying amount of its goodwill. During the first quarter 2020, we determined a triggering event occurred that required us to evaluate our goodwill for impairment, and we recorded an impairment charge as a result of that assessment. See Note 2, Goodwill and Long-Lived Assets, for additional information.

We adopted the guidance in ASU 2018-13, Fair Value Measurement (Topic 820) - Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement on January 1, 2020. This ASU modifies the disclosure requirements in Topic 820, Fair Value Measurements, by removing, modifying, or adding certain disclosures. The adoption of ASU 2018-13 did not have a material impact on the condensed consolidated financial statements.