Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Loss Contingencies [Line Items]
Subscriber funds		$ 1,700	$ 2,000
First Data | First Data Subsidiary Merchant Matters
Loss Contingencies [Line Items]
Payment for legal settlement	$ 40
Loss contingency accrual		32	$ 43
First Data | First Data Subsidiary Merchant Matters | Minimum
Loss Contingencies [Line Items]
Estimated range of exposure		0
First Data | First Data Subsidiary Merchant Matters | Maximum
Loss Contingencies [Line Items]
Estimated range of exposure		$ 60