Notional Amounts and Fair Values for All Derivative Instruments Included in the Consolidated Balance Sheets (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	$ 2,307	$ 2,356	$ 1,964
Fair value - Derivative Liabilities	1,096	1,344	1,157
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	762	812	593
Fair value - Derivative Liabilities	3	5	27
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Fair Value Hedging
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	640	662	422
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	4,080	4,080
Fair value - Derivative Assets	640	662	422
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	122	150	171
Fair value - Derivative Liabilities	3	5	27
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	250	250
Fair value - Derivative Liabilities	3	5	9
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	1,000	1,500	2,000
Fair value - Derivative Assets	64	59	42
Fair value - Derivative Liabilities			18
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	1,500
Fair value - Derivative Assets	58	91	128
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	500	1,500
Fair value - Derivative Assets			1
Nondesignated
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	1,545	1,544	1,371
Fair value - Derivative Liabilities	1,093	1,339	1,130
Nondesignated | Risk Management and Other Business Purposes
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	461	307	310
Fair value - Derivative Liabilities	67	136	67
Nondesignated | Risk Management and Other Business Purposes | Interest Rate Swap | Long-Term Debt
Derivatives, Fair Value [Line Items]
Notional amount	136	311	373
Fair value - Derivative Assets	1	1	2
Fair value - Derivative Liabilities	1	3	6
Nondesignated | Risk Management and Other Business Purposes | Interest Rate Contract | Mortgage Servicing Rights
Derivatives, Fair Value [Line Items]
Notional amount	8,577	3,077	16,452
Fair value - Derivative Assets	238	187	196
Fair value - Derivative Liabilities			31
Nondesignated | Risk Management and Other Business Purposes | Forward Contracts | Assets Held-for-sale
Derivatives, Fair Value [Line Items]
Notional amount	7,382	5,705	2,210
Fair value - Derivative Assets	9	8	6
Fair value - Derivative Liabilities	37	54	9
Nondesignated | Risk Management and Other Business Purposes | Foreign Exchange Contract
Derivatives, Fair Value [Line Items]
Notional amount			1,681
Fair value - Derivative Assets			2
Fair value - Derivative Liabilities			2
Nondesignated | Risk Management and Other Business Purposes | Put Option
Derivatives, Fair Value [Line Items]
Notional amount		978	901
Fair value - Derivative Liabilities		1	7
Nondesignated | Risk Management and Other Business Purposes | Warrant
Derivatives, Fair Value [Line Items]
Notional amount	475	223	205
Fair value - Derivative Assets	213	111	104
Nondesignated | Risk Management and Other Business Purposes | Swap
Derivatives, Fair Value [Line Items]
Notional amount	532	436	416
Fair value - Derivative Liabilities	29	78	12
Nondesignated | Customer Accommodation [Member]
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	1,084	1,237	1,061
Fair value - Derivative Liabilities	1,026	1,203	1,063
Nondesignated | Customer Accommodation [Member] | Interest Rate Contract
Derivatives, Fair Value [Line Items]
Notional amount	27,147	30,000	28,607
Fair value - Derivative Assets	671	774	675
Fair value - Derivative Liabilities	691	795	700
Nondesignated | Customer Accommodation [Member] | Foreign Exchange Contract
Derivatives, Fair Value [Line Items]
Notional amount	18,020	17,909	20,848
Fair value - Derivative Assets	237	294	293
Fair value - Derivative Liabilities	221	275	281
Nondesignated | Customer Accommodation [Member] | Interest Rate Lock Commitments
Derivatives, Fair Value [Line Items]
Notional amount	4,887	3,835	1,729
Fair value - Derivative Assets	55	33	6
Fair value - Derivative Liabilities	1	1	2
Nondesignated | Customer Accommodation [Member] | Commodity Contract
Derivatives, Fair Value [Line Items]
Notional amount	2,316	2,074	1,939
Fair value - Derivative Assets	120	134	85
Fair value - Derivative Liabilities	112	130	78
Nondesignated | Customer Accommodation [Member] | Derivative | Certificates of Deposit
Derivatives, Fair Value [Line Items]
Notional amount	25	34	42
Fair value - Derivative Assets	1	2	2
Fair value - Derivative Liabilities	$ 1	$ 2	$ 2