Notional Amounts and Fair Values for All Derivative Instruments Included in the Consolidated Balance Sheets (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Derivatives, Fair Value
Fair value - Derivative Assets	$ 1,565	$ 1,553
Fair value - Derivative Liabilities	628	754
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges
Derivatives, Fair Value
Fair value - Derivative Assets	385	332
Fair value - Derivative Liabilities	7	34
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Fair Value Hedging
Derivatives, Fair Value
Fair value - Derivative Assets	350	292
Fair value - Derivative Liabilities	7	13
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Fair Value Hedging | Interest Rate Swap | Long-Term Debt
Derivatives, Fair Value
Notional amount	3,855	3,205
Fair value - Derivative Assets	350	292
Fair value - Derivative Liabilities	7	13
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Cash Flow Hedging
Derivatives, Fair Value
Fair value - Derivative Assets	35	40
Fair value - Derivative Liabilities		21
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Cash Flow Hedging | Interest Rate Swap | Commercial and Industrial Loans
Derivatives, Fair Value
Notional amount	2,200	2,200
Fair value - Derivative Assets	35	40
Fair value - Derivative Liabilities		21
Nondesignated
Derivatives, Fair Value
Fair value - Derivative Assets	1,180	1,221
Fair value - Derivative Liabilities	621	720
Nondesignated | Risk Management and Other Business Purposes
Derivatives, Fair Value
Fair value - Derivative Assets	588	538
Fair value - Derivative Liabilities	70	63
Nondesignated | Risk Management and Other Business Purposes | Interest Rate Contract | Servicing Rights
Derivatives, Fair Value
Notional amount	5,362	4,092
Fair value - Derivative Assets	176	141
Fair value - Derivative Liabilities	5	14
Nondesignated | Risk Management and Other Business Purposes | Forward Contracts | Assets Held-for-sale
Derivatives, Fair Value
Notional amount	1,074	1,448
Fair value - Derivative Assets		13
Fair value - Derivative Liabilities	11	1
Nondesignated | Risk Management and Other Business Purposes | Warrant
Derivatives, Fair Value
Notional amount	685	664
Fair value - Derivative Assets	412	384
Nondesignated | Risk Management and Other Business Purposes | Swap
Derivatives, Fair Value
Notional amount	895	947
Fair value - Derivative Liabilities	54	48
Nondesignated | Customer Accommodation
Derivatives, Fair Value
Fair value - Derivative Assets	592	683
Fair value - Derivative Liabilities	551	657
Nondesignated | Customer Accommodation | Interest Rate Contract
Derivatives, Fair Value
Notional amount	27,383	28,112
Fair value - Derivative Assets	300	329
Fair value - Derivative Liabilities	309	339
Nondesignated | Customer Accommodation | Foreign Exchange Contract
Derivatives, Fair Value
Notional amount	18,121	19,688
Fair value - Derivative Assets	175	276
Fair value - Derivative Liabilities	142	252
Nondesignated | Customer Accommodation | Interest Rate Lock Commitments
Derivatives, Fair Value
Notional amount	836	924
Fair value - Derivative Assets	17	12
Fair value - Derivative Liabilities		1
Nondesignated | Customer Accommodation | Commodity Contract
Derivatives, Fair Value
Notional amount	3,684	3,300
Fair value - Derivative Assets	100	66
Fair value - Derivative Liabilities	$ 100	$ 65