Notional Amounts and Fair Values for All Derivative Instruments Included in the Consolidated Balance Sheets (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	$ 2,101	$ 2,356	$ 1,826
Fair value - Derivative Liabilities	1,046	1,344	1,183
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	697	812	528
Fair value - Derivative Liabilities	4	5	23
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Fair Value Hedging
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	562	662	376
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	4,355
Fair value - Derivative Assets	562	662	376
Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	135	150	152
Fair value - Derivative Liabilities	4	5	23
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	302
Fair value - Derivative Liabilities	4	5	8
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	58	59	13
Fair value - Derivative Liabilities			15
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	77	91	135
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			4
Nondesignated
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	1,404	1,544	1,298
Fair value - Derivative Liabilities	1,042	1,339	1,160
Nondesignated | Risk Management and Other Business Purposes
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	380	307	227
Fair value - Derivative Liabilities	34	136	84
Nondesignated | Risk Management and Other Business Purposes | Interest Rate Swap | Long-Term Debt
Derivatives, Fair Value [Line Items]
Notional amount	195	311	457
Fair value - Derivative Assets	1	1	3
Fair value - Derivative Liabilities	2	3	7
Nondesignated | Risk Management and Other Business Purposes | Interest Rate Contract | Mortgage Servicing Rights
Derivatives, Fair Value [Line Items]
Notional amount	8,077	3,077	21,677
Fair value - Derivative Assets	201	187	138
Fair value - Derivative Liabilities			25
Nondesignated | Risk Management and Other Business Purposes | Forward Contracts | Assets Held-for-sale
Derivatives, Fair Value [Line Items]
Notional amount	8,769	5,705	2,529
Fair value - Derivative Assets	21	8	3
Fair value - Derivative Liabilities	10	54	10
Nondesignated | Risk Management and Other Business Purposes | Foreign Exchange Contract
Derivatives, Fair Value [Line Items]
Notional amount			2,202
Fair value - Derivative Assets			7
Fair value - Derivative Liabilities			6
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	228	223	175
Fair value - Derivative Assets	157	111	76
Nondesignated | Risk Management and Other Business Purposes | Swap
Derivatives, Fair Value [Line Items]
Notional amount	507	436	363
Fair value - Derivative Liabilities	22	78	28
Nondesignated | Customer Accommodation [Member]
Derivatives, Fair Value [Line Items]
Fair value - Derivative Assets	1,024	1,237	1,071
Fair value - Derivative Liabilities	1,008	1,203	1,076
Nondesignated | Customer Accommodation [Member] | Interest Rate Contract
Derivatives, Fair Value [Line Items]
Notional amount	26,185	30,000	28,748
Fair value - Derivative Assets	655	774	629
Fair value - Derivative Liabilities	674	795	656
Nondesignated | Customer Accommodation [Member] | Foreign Exchange Contract
Derivatives, Fair Value [Line Items]
Notional amount	17,473	17,909	17,928
Fair value - Derivative Assets	191	294	308
Fair value - Derivative Liabilities	178	275	301
Nondesignated | Customer Accommodation [Member] | Interest Rate Lock Commitments
Derivatives, Fair Value [Line Items]
Notional amount	4,307	3,835	1,523
Fair value - Derivative Assets	20	33	9
Fair value - Derivative Liabilities	3	1	1
Nondesignated | Customer Accommodation [Member] | Commodity Contract
Derivatives, Fair Value [Line Items]
Notional amount	2,110	2,074	1,949
Fair value - Derivative Assets	156	134	123
Fair value - Derivative Liabilities	151	130	116
Nondesignated | Customer Accommodation [Member] | Derivative | Certificates of Deposit
Derivatives, Fair Value [Line Items]
Notional amount	33	34	54
Fair value - Derivative Assets	2	2	2
Fair value - Derivative Liabilities	$ 2	$ 2	$ 2