Debt - Schedule of Short-Term Debt (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2026	Dec. 31, 2025
Short-term Debt
Total Short-term borrowings	$ 4,226	$ 2,729
Commercial Paper
Short-term Debt
Commercial paper	$ 7,000
Commercial Paper \| FIS Credit Agreements \| Euro-commercial paper notes ("ECP Notes")
Short-term Debt
Short term debt, weighted average interest rate	2.40%
Maturities	183 days
Commercial paper	$ 114	117
Commercial Paper \| FIS Credit Agreements \| U.S. commercial paper notes ("USCP Notes")
Short-term Debt
Short term debt, weighted average interest rate	4.00%
Maturities	397 days
Commercial paper	$ 4,112	$ 2,612

Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days.

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