Notional Amounts and Fair Values for All Derivative Instruments Included in the Consolidated Balance Sheets (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	$ 2,356	$ 2,074
Fair value - Derivative Liabilities	1,344	1,314
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	812	607
Fair value - Derivative Liabilities	5	31
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Fair Value Hedging
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	662	442
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Fair Value Hedging | Interest Rate Swap | Long-Term Debt
Derivatives, Fair Value [Line Items]
Notional amount	4,080	4,355
Fair value - Derivative Assets	662	442
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	150	165
Fair value - Derivative Liabilities	5	31
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Cash Flow Hedging | Interest Rate Swap | Long-Term Debt
Derivatives, Fair Value [Line Items]
Notional amount	250	1,190
Fair value - Derivative Liabilities	5	31
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Cash Flow Hedging | Interest Rate Swap | Commercial And Industrial Loans [Member]
Derivatives, Fair Value [Line Items]
Notional amount	1,500	3,000
Fair value - Derivative Assets	59	8
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Cash Flow Hedging | Interest Rate Floor | Commercial And Industrial Loans [Member]
Derivatives, Fair Value [Line Items]
Notional amount	1,500	1,500
Fair value - Derivative Assets	91	153
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Cash Flow Hedging | Interest Rate Cap | Long-Term Debt
Derivatives, Fair Value [Line Items]
Notional amount	500	1,500
Fair value - Derivative Assets		4
Nondesignated
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	1,544	1,467
Fair value - Derivative Liabilities	1,339	1,283
Nondesignated | Risk Management and Other Business Purposes
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	307	317
Fair value - Derivative Liabilities	136	126
Nondesignated | Risk Management and Other Business Purposes | Interest Rate Swap | Long-Term Debt
Derivatives, Fair Value [Line Items]
Notional amount	311	173
Fair value - Derivative Assets	1	3
Fair value - Derivative Liabilities	3	1
Nondesignated | Risk Management and Other Business Purposes | Interest Rate Contract | Mortgage Servicing Rights
Derivatives, Fair Value [Line Items]
Notional amount	3,077	12,477
Fair value - Derivative Assets	187	141
Fair value - Derivative Liabilities		81
Nondesignated | Risk Management and Other Business Purposes | Forward Contracts | Assets Held-for-sale
Derivatives, Fair Value [Line Items]
Notional amount	5,705	6,389
Fair value - Derivative Assets	8	90
Fair value - Derivative Liabilities	54	14
Nondesignated | Risk Management and Other Business Purposes | Foreign Exchange Contract
Derivatives, Fair Value [Line Items]
Notional amount		2,494
Fair value - Derivative Assets		4
Fair value - Derivative Liabilities		4
Nondesignated | Risk Management and Other Business Purposes | Put Option
Derivatives, Fair Value [Line Items]
Notional amount	978	769
Fair value - Derivative Liabilities	1	8
Nondesignated | Risk Management and Other Business Purposes | Warrant
Derivatives, Fair Value [Line Items]
Notional amount	223	175
Fair value - Derivative Assets	111	79
Nondesignated | Risk Management and Other Business Purposes | Swap
Derivatives, Fair Value [Line Items]
Notional amount	436	363
Fair value - Derivative Liabilities	78	18
Nondesignated | Customer Accommodation [Member]
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	1,237	1,150
Fair value - Derivative Liabilities	1,203	1,157
Nondesignated | Customer Accommodation [Member] | Interest Rate Contract
Derivatives, Fair Value [Line Items]
Notional amount	30,000	26,817
Fair value - Derivative Assets	774	701
Fair value - Derivative Liabilities	795	735
Nondesignated | Customer Accommodation [Member] | Foreign Exchange Contract
Derivatives, Fair Value [Line Items]
Notional amount	17,909	17,998
Fair value - Derivative Assets	294	339
Fair value - Derivative Liabilities	275	319
Nondesignated | Customer Accommodation [Member] | Interest Rate Lock Commitments
Derivatives, Fair Value [Line Items]
Notional amount	3,835	1,772
Fair value - Derivative Assets	33	9
Fair value - Derivative Liabilities	1	9
Nondesignated | Customer Accommodation [Member] | Commodity Contract
Derivatives, Fair Value [Line Items]
Notional amount	2,074	1,878
Fair value - Derivative Assets	134	99
Fair value - Derivative Liabilities	130	92
Nondesignated | Customer Accommodation [Member] | Derivative | Certificates of Deposit
Derivatives, Fair Value [Line Items]
Notional amount	34	70
Fair value - Derivative Assets	2	2
Fair value - Derivative Liabilities	$ 2	$ 2