Guarantees and Contingent Liabilities - Additional Information (Detail) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Guarantees And Contingent Liabilities (Textual) [Abstract]
Liability related to remaining Visa Litigation, carrying amount	$ 19
United States Attorney's office settlement net payment	453
Office of the Comptroller of the Currency civil money penalty	75
Financial Crimes Enforcement Network settlement net payment	70
Federal Reserve civil money penalty	15
Settlement and civil money penalty payment	613
Asset Sales [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Representation and warranty reserve	12	$ 13
Unresolved representation and warranty claims from GSEs	10	$ 9
Merchant Processing [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Value of airline tickets purchased to deliver at future date through card transactions	10,700
Company held collateral in escrow deposits, letters of credit and indemnities from financial institutions and liens on various assets	622
Liability primarily related to airline processing arrangements	$ 47
Visa Class B Shares [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Number of shares sold	0.3
Remaining shares held by the Company	2.4