Contingent Liabilities - Additional Information (Detail)		1 Months Ended		12 Months Ended
	Jan. 14, 2014 case	Jun. 30, 2015 USD ($) shares	Jan. 31, 2015 trust	Dec. 31, 2015 USD ($) shares	Dec. 31, 2013 USD ($) lawsuit	Sep. 30, 2015 USD ($)
Loss Contingencies [Line Items]
Possible loss in future periods in excess of accrual				$ 125,000,000
Legal settlement charge					$ 19,200,000
Number of lawsuits where settled charges have been recorded | lawsuit					2
Number of opt-out cases filed by merchants | case	30
Remaining Visa shares held by Northern Trust, original cost basis						$ 0
Visa Class B
Loss Contingencies [Line Items]
Visa redemption gain		$ 99,900,000		$ 99,900,000
Common stock issued (in shares) | shares		1,000,000.0		1,000,000.0
Visa class b common stock shares held | shares				5,200,000
Northern Trust Fiduciary Services (Guernsey) Limited | Subsidiaries [Member]
Loss Contingencies [Line Items]
Number of administrated trusts served as trustee on | trust			2