Derivatives (Derivative Financial Instruments - Additional Information) (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Jun. 30, 2009	Sep. 30, 2017	Dec. 31, 2016
Derivative
Valuation adjustments related to the credit risk associated with counterparties of customer accomodation derivative contracts		$ 6	$ 6
Notional amount of the risk participation agreements		$ 2,820	2,467
Percentage of Vantiv Holding, LLC sold to Advent for cash and warrants	51.00%
Interest Rate Contract | Credit Risk
Derivative
Credit Risk Derivatives Average Remaining Life		2 years 9 months 18 days
Fair value of risk participation agreements		$ 5	4
Interest Rate Contract | Cash Flow Hedging
Derivative
Maximum length of time hedged in cash flow hedge		2 years 3 months
Deferred gains, net of tax, on cash flow hedges were recorded in accumulated other comprehensive income		$ 1	10
Net deferred gains, net of tax, recorded in accumulated other comprehensive income are expected to be reclassified into earnings during the next twelve months		3
Total collateral
Derivative
Derivative Asset, Fair Value, Amount Not Offset Against Collateral		458	444
Derivative Liability, Fair Value, Amount Offset Against Collateral		384	$ 399
Amount of variation margin payment applied to derivative asset contracts		31
Amount of variation margin payment applied to derivative liability contracts		$ 83