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Related Party Transactions (Details) - USD ($) shares in Millions			12 Months Ended
	Dec. 14, 2020	Dec. 04, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2020
Fiserv
Related Party Transaction [Line Items]
Secondary public offering (in shares)	$ 20,100,000
New Omaha
Related Party Transaction [Line Items]
Number of shares to be repurchased (in shares)	1.8
Share repurchase amount		$ 200,000,000
New Omaha \| Fiserv
Related Party Transaction [Line Items]
Ownership percentage by noncontrolling owner	13.00%		16.00%
Merchant Alliances
Related Party Transaction [Line Items]
Amounts due from unconsolidated merchant alliances			$ 37,000,000	$ 35,000,000
Merchant Alliances \| Merchant Alliances, Fees
Related Party Transaction [Line Items]
Processing, administrative service, and other fees			183,000,000	76,000,000
Merchant Alliances \| Related Party Fees
Related Party Transaction [Line Items]
Processing, administrative service, and other fees			$ 236,000,000	112,000,000	$ 28,000,000
Joint Venture \| Banc of America Merchant Services
Related Party Transaction [Line Items]
Percentage of interest in joint venture			51.00%			51.00%
Affiliated Entity \| Related Party Fees \| Lending Solutions Business And Investment Services Business
Related Party Transaction [Line Items]
Processing, administrative service, and other fees			$ 58,000,000	$ 36,000,000	$ 30,000,000