Guarantees and Contingent Liabilities - Additional Information (Detail) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Airline Processing Arrangements [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Value of airline tickets purchased to deliver at future date through card transactions	$ 8,700
Representation and Warranty [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Carrying Amount	14	$ 9
Unresolved representation and warranty claims from GSEs	14	$ 10
Escrow Deposits Letters of Credit Indemnities [Member] | Airline Processing Arrangements [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Collateral Held	502
Merchant Escrow Deposits [Member] | Airline Processing Arrangements [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Collateral Held	$ 115