DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (Policies)	3 Months Ended
Mar. 31, 2021
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. Investments in entities in which we do not have a controlling financial interest are accounted for at fair value, as available-for-sale securities or at cost adjusted for observable price changes and impairments, as appropriate.
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.
Reclassifications	Reclassifications Certain reclassifications have been made to the condensed consolidated financial statements of prior periods to conform to the current period presentation.
Adoption of New Accounting Standards	Adoption of New Accounting Standards We adopted the guidance in ASU 2019-12, Income Taxes (Topic 740) - Simplifying the Accounting for Income Taxes, on January 1, 2021. This ASU simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. The adoption of ASU 2019-12 did not have a material impact on the condensed consolidated financial statements. We adopted the guidance in ASU 2020-03, Codification Improvements to Financial Instruments, on January 1, 2021. This ASU amends a wide variety of Topics in the Codification, including revolving-debt arrangements and allowance for credit losses related to leases. The adoption of ASU 2020-03 did not have a material impact on the condensed consolidated financial statements. We early adopted the guidance in ASU 2020-06, Debt - Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging - Contracts in Entity's Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity's Own Equity, on January 1, 2021. The ASU removes the separation models for convertible debt with a cash conversion feature or convertible instruments with a beneficial conversion feature. Additionally, the ASU removes certain conditions for equity classification related to contracts in an entity’s own equity (e.g., warrants) and amends certain guidance related to the computation of earnings per share for convertible instruments and contracts in an entity’s own equity. As a result of adopting ASU 2020-06, we recorded a $67.0 million net reduction to additional paid-in capital, a $19.0 million increase to non-current liabilities and a $48.0 million reduction to our opening accumulated deficit as of January 1, 2021. See Note 5, Financing Arrangements, for additional information.

DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (Policies)

3 Months Ended

Mar. 31, 2021

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. Investments in entities in which we do not have a controlling financial interest are accounted for at fair value, as available-for-sale securities or at cost adjusted for observable price changes and impairments, as appropriate.

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.

Reclassifications

Certain reclassifications have been made to the condensed consolidated financial statements of prior periods to conform to the current period presentation.

Adoption of New Accounting Standards

We adopted the guidance in ASU 2019-12, Income Taxes (Topic 740) - Simplifying the Accounting for Income Taxes, on January 1, 2021. This ASU simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. The adoption of ASU 2019-12 did not have a material impact on the condensed consolidated financial statements.

We adopted the guidance in ASU 2020-03, Codification Improvements to Financial Instruments, on January 1, 2021. This ASU amends a wide variety of Topics in the Codification, including revolving-debt arrangements and allowance for credit losses related to leases. The adoption of ASU 2020-03 did not have a material impact on the condensed consolidated financial statements.

We early adopted the guidance in ASU 2020-06, Debt - Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging - Contracts in Entity's Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity's Own Equity, on January 1, 2021. The ASU removes the separation models for convertible debt with a cash conversion feature or convertible instruments with a beneficial conversion feature. Additionally, the ASU removes certain conditions for equity classification related to contracts in an entity’s own equity (e.g., warrants) and amends certain guidance related to the computation of earnings per share for convertible instruments and contracts in an entity’s own equity. As a result of adopting ASU 2020-06, we recorded a $67.0 million net reduction to additional paid-in capital, a $19.0 million increase to non-current liabilities and a $48.0 million reduction to our opening accumulated deficit as of January 1, 2021. See Note 5, Financing Arrangements, for additional information.