Notional Amounts and Fair Values for All Derivative Instruments Included in the Consolidated Balance Sheets (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Derivatives, Fair Value
Fair value - Derivative Assets	$ 1,454	$ 1,553
Fair value - Derivative Liabilities	623	754
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges
Derivatives, Fair Value
Fair value - Derivative Assets	361	332
Fair value - Derivative Liabilities	23	34
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Fair Value Hedging
Derivatives, Fair Value
Fair value - Derivative Assets	325	292
Fair value - Derivative Liabilities	11	13
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Fair Value Hedging | Interest Rate Swap | Long-Term Debt
Derivatives, Fair Value
Notional amount	3,205	3,205
Fair value - Derivative Assets	325	292
Fair value - Derivative Liabilities	11	13
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Cash Flow Hedging
Derivatives, Fair Value
Fair value - Derivative Assets	36	40
Fair value - Derivative Liabilities	12	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	36	40
Fair value - Derivative Liabilities	12	21
Nondesignated
Derivatives, Fair Value
Fair value - Derivative Assets	1,093	1,221
Fair value - Derivative Liabilities	600	720
Nondesignated | Risk Management and Other Business Purposes
Derivatives, Fair Value
Fair value - Derivative Assets	501	538
Fair value - Derivative Liabilities	53	63
Nondesignated | Risk Management and Other Business Purposes | Interest Rate Contract | Servicing Rights
Derivatives, Fair Value
Notional amount	5,277	4,092
Fair value - Derivative Assets	151	141
Fair value - Derivative Liabilities	9	14
Nondesignated | Risk Management and Other Business Purposes | Forward Contracts | Assets Held-for-sale
Derivatives, Fair Value
Notional amount	1,844	1,448
Fair value - Derivative Assets	2	13
Fair value - Derivative Liabilities	1	1
Nondesignated | Risk Management and Other Business Purposes | Warrant
Derivatives, Fair Value
Notional amount	616	664
Fair value - Derivative Assets	348	384
Nondesignated | Risk Management and Other Business Purposes | Swap
Derivatives, Fair Value
Notional amount	918	947
Fair value - Derivative Liabilities	43	48
Nondesignated | Customer Accommodation
Derivatives, Fair Value
Fair value - Derivative Assets	592	683
Fair value - Derivative Liabilities	547	657
Nondesignated | Customer Accommodation | Interest Rate Contract
Derivatives, Fair Value
Notional amount	27,418	28,112
Fair value - Derivative Assets	306	329
Fair value - Derivative Liabilities	315	339
Nondesignated | Customer Accommodation | Foreign Exchange Contract
Derivatives, Fair Value
Notional amount	20,020	19,688
Fair value - Derivative Assets	204	276
Fair value - Derivative Liabilities	164	252
Nondesignated | Customer Accommodation | Interest Rate Lock Commitments
Derivatives, Fair Value
Notional amount	994	924
Fair value - Derivative Assets	16	12
Fair value - Derivative Liabilities		1
Nondesignated | Customer Accommodation | Commodity Contract
Derivatives, Fair Value
Notional amount	3,179	3,300
Fair value - Derivative Assets	66	66
Fair value - Derivative Liabilities	$ 68	$ 65