Guarantees and Contingent Liabilities - Additional Information (Detail) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Airline Processing Arrangements [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Value of airline tickets purchased to deliver at future date through card transactions	$ 7,700
Representation and Warranty [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Carrying Amount	18	$ 19
Unresolved representation and warranty claims from GSEs	15	$ 13
Escrow Deposits Letters of Credit Indemnities [Member] | Airline Processing Arrangements [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Collateral Held	638
Merchant Escrow Deposits [Member] | Airline Processing Arrangements [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Carrying Amount	$ 185