Basis of Presentation (Policies)	9 Months Ended
Basis of Presentation (Policies)	Sep. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The unaudited financial information included in this report includes the accounts of FIS and its subsidiaries prepared in accordance with U.S. generally accepted accounting principles and the instructions to Form 10-Q and Article 10 of Regulation S-X. All adjustments considered necessary for a fair presentation have been included. This report should be read in conjunction with the Company's Annual Report on Form 10-K for the year ended December 31, 2024. The preparation of these consolidated financial statements in conformity with United States ("U.S.") generally accepted accounting principles ("GAAP") and the related rules and regulations of the U.S. Securities and Exchange Commission ("SEC" or "Commission") requires our management to make estimates, judgments and assumptions that affect the reported amounts of assets, liabilities, revenue and expenses, and the related disclosure of contingent assets and liabilities. The inputs into management's critical and significant accounting estimates consider the economic impact of inflation and economic growth rates. These estimates may change as new events occur and additional information is obtained. Future actual results could differ materially from these estimates. To the extent that there are differences between these estimates, judgments and assumptions and actual results, our consolidated financial statements will be affected.
Recently Adopted Accounting Guidance and Recent Accounting Guidance Not Yet Adopted	Recently Adopted Accounting Guidance No recently adopted accounting pronouncements are expected to have a material impact on our consolidated financial statements or disclosures. Recent Accounting Guidance Not Yet Adopted In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The ASU requires that an entity disclose specific categories in the effective tax rate reconciliation and provide additional information for reconciling items that meet a quantitative threshold. The ASU also introduces requirements for disaggregated disclosures of federal, state and foreign income tax expense and taxes paid. The amendments are effective for fiscal years beginning after December 31, 2024, and should be applied prospectively, although retrospective application is permitted. The Company will adopt the amendments on an annual basis beginning with the current fiscal year. These amendments will expand the Company’s annual income tax disclosures but will not impact the consolidated balance sheets, results of operations or cash flows. In November 2024, the FASB issued ASU 2024-03, Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses. The ASU requires disclosure of disaggregated information about specific categories underlying certain income statement expense line items. This guidance is effective for annual periods beginning after December 15, 2026, and interim periods beginning after December 15, 2027. Early adoption is permitted and is effective on either a prospective basis or retrospective basis. The Company is currently evaluating the impact of adoption on our financial disclosures. In July 2025, the FASB issued ASU 2025-05, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses for Accounts Receivable and Contract Assets. The ASU provides a practical expedient that allows entities to assume conditions existing as of the balance sheet date remain unchanged over the life of the asset when estimating credit losses for current trade receivables and current contract assets arising from transactions accounted for under Topic 606. The amendments are effective for annual reporting periods beginning after December 15, 2025, and for interim periods within those annual periods, with early adoption permitted. The amendments should be applied prospectively. The Company is currently evaluating the impact of this ASU and believes that adoption will not have a material effect on the consolidated financial statements or related disclosures. In September 2025, the FASB issued ASU 2025-06, Intangibles – Goodwill and Other – Internal-use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software. This guidance updates requirements for capitalizing internal-use software costs by replacing the current stage-based model with a principles-based approach. Under the new ASU, capitalization of eligible software development costs begins when management has authorized and committed to funding the project and it is probable the project will be completed and used as intended. Entities must also consider whether significant uncertainty exists regarding the development activities. The amendments are effective for annual reporting periods beginning after December 15, 2027, including interim periods within those years. Early adoption is permitted. The amendments may be applied prospectively, on a modified retrospective basis for in-process projects, or retrospectively. The Company is currently evaluating the impact of this ASU on its consolidated financial statements and related disclosures.