Guarantees and Contingent Liabilities - Additional Information (Detail) - USD ($) shares in Millions, $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Asset Sales [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Representation and warranty reserve	$ 11	$ 11	$ 13
Unresolved representation and warranty claims from GSEs	14	14	$ 9
Merchant Processing [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Value of airline tickets purchased to deliver at future date through card transactions	8,200	8,200
Company held collateral in escrow deposits, letters of credit and indemnities from financial institutions and liens on various assets	452	452
Liability primarily related to airline processing arrangements	$ 38	$ 38
Visa Class B Shares [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Number of shares sold	0.4	0.9
Remaining shares held by the Company	1.8	1.8