Background and Basis of Presentation (Policies)	12 Months Ended
Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Significant Accounting Policies	The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the U.S. (“GAAP”).
Use of Estimates	The preparation of financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and related disclosures. These estimates are based on information available as of the date of the consolidated financial statements. The Company believes that the estimates used in the preparation of the consolidated financial statements are reasonable. Actual results could differ from these estimates. Certain prior year amounts have been reclassified to conform to the current year presentation. These reclassifications had no impact on the Company’s consolidated financial condition, results of operations or changes in stockholders’ equity.
Consolidation	Principles of Consolidation The accompanying consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. The Company’s policy is to consolidate all entities in which it owns more than 50% of the outstanding voting stock unless it does not control the entity. However, the Company did not have a controlling voting interest in any entity other than its wholly-owned subsidiaries in the periods presented in the accompanying consolidated financial statements. It is also the Company’s policy to consolidate any VIEs for which the Company is the primary beneficiary, as defined by GAAP. On this basis, the Company consolidates the Discover Card Master Trust I (“DCMT”) and the Discover Card Execution Note Trust (“DCENT”) as well as the student loan securitization trust. The Company is deemed to be the primary beneficiary of each of these trusts since it is, for each, the trust Servicer and the holder of both the residual interest and the majority of the most subordinated interests. Because of those involvements, the Company has, for each trust, (i) the power to direct the activities that most significantly impact the economic performance of the trust and (ii) the obligation (or right) to absorb losses (or receive benefits) of the trust that could potentially be significant. The Company has determined that it was not the primary beneficiary of any other VIE during the years ended December 31, 2023, 2022 and 2021. For investments in any entities in which the Company owns 50% or less of the outstanding voting stock but in which the Company has significant influence over operating and financial decisions, the Company applies the equity method of accounting. The Company also applies the equity method to its investments in qualified affordable housing projects and similar tax credit partnerships. In cases where the Company’s equity investment is less than 20% and significant influence does not exist, such investments are carried at cost as they typically do not have readily determinable fair values, and are adjusted for any impairment in value. Investments in actively traded stock are carried at fair value with changes in fair value recorded as an adjustment to earnings.

Background and Basis of Presentation (Policies)

12 Months Ended

Dec. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Basis of Presentation and Significant Accounting Policies

The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the U.S. (“GAAP”).

Use of Estimates

The preparation of financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and related disclosures. These estimates are based on information available as of the date of the consolidated financial statements. The Company believes that the estimates used in the preparation of the consolidated financial statements are reasonable. Actual results could differ from these estimates.

Certain prior year amounts have been reclassified to conform to the current year presentation. These reclassifications had no impact on the Company’s consolidated financial condition, results of operations or changes in stockholders’ equity.

Consolidation

Principles of Consolidation

The accompanying consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. The Company’s policy is to consolidate all entities in which it owns more than 50% of the outstanding voting stock unless it does not control the entity. However, the Company did not have a controlling voting interest in any entity other than its wholly-owned subsidiaries in the periods presented in the accompanying consolidated financial statements.

It is also the Company’s policy to consolidate any VIEs for which the Company is the primary beneficiary, as defined by GAAP. On this basis, the Company consolidates the Discover Card Master Trust I (“DCMT”) and the Discover Card Execution Note Trust (“DCENT”) as well as the student loan securitization trust. The Company is deemed to be the primary beneficiary of each of these trusts since it is, for each, the trust Servicer and the holder of both the residual interest and the majority of the most subordinated interests. Because of those involvements, the Company has, for each trust, (i) the power to direct the activities that most significantly impact the economic performance of the trust and (ii) the obligation (or right) to absorb losses (or receive benefits) of the trust that could potentially be significant. The Company has determined that it was not the primary beneficiary of any other VIE during the years ended December 31, 2023, 2022 and 2021.

For investments in any entities in which the Company owns 50% or less of the outstanding voting stock but in which the Company has significant influence over operating and financial decisions, the Company applies the equity method of accounting. The Company also applies the equity method to its investments in qualified affordable housing projects and similar tax credit partnerships. In cases where the Company’s equity investment is less than 20% and significant influence does not exist, such investments are carried at cost as they typically do not have readily

determinable fair values, and are adjusted for any impairment in value. Investments in actively traded stock are carried at fair value with changes in fair value recorded as an adjustment to earnings.