Fair Value Measurement and Election - Additional Information (Detail) (USD $)	3 Months Ended			9 Months Ended					3 Months Ended		9 Months Ended				3 Months Ended		9 Months Ended			9 Months Ended						3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		12 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended						9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011	Sep. 30, 2012		Sep. 30, 2011	Dec. 31, 2011		Sep. 30, 2012 Fair Value, Inputs, Level 2 [Member] Property Subject to Operating Lease [Member]	Sep. 30, 2011 Fair Value, Inputs, Level 2 [Member] Property Subject to Operating Lease [Member]	Sep. 30, 2012 Fair Value, Inputs, Level 2 [Member] Property Subject to Operating Lease [Member]	Sep. 30, 2011 Fair Value, Inputs, Level 2 [Member] Property Subject to Operating Lease [Member]	Sep. 30, 2012 Total Return Swap Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2011 Total Return Swap Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2012 Interest Rate Lock Commitments	Sep. 30, 2011 Interest Rate Lock Commitments	Sep. 30, 2012 Interest Rate Lock Commitments	Sep. 30, 2011 Interest Rate Lock Commitments	Sep. 30, 2012 Collateralized Debt Obligations [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2012 Asset-backed Securities [Member] Trading Assets [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2012 Asset-backed Securities [Member] Available-for-sale Securities [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2012 Asset-backed Securities [Member] Student Loans [Member]	Dec. 31, 2011 Equity Securities, Coca Cola Fair Value, Inputs, Level 3 [Member]	Sep. 30, 2012 Trading Account Assets [Member] Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2011 Trading Account Assets [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2012 Residential Mortgage, Loans Held For Sale [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2011 Residential Mortgage, Loans Held For Sale [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2012 Residential Mortgage, Loans Held For Sale [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2011 Residential Mortgage, Loans Held For Sale [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2012 Residential Mortgage, Loans Held For Sale [Member] Nonperforming Financing Receivable [Member]	Dec. 31, 2011 Residential Mortgage, Loans Held For Sale [Member] Nonperforming Financing Receivable [Member]	Sep. 30, 2012 Residential Mortgage, Loans Held For Sale [Member] Nonperforming Financing Receivable [Member]	Sep. 30, 2011 Residential Mortgage, Loans Held For Sale [Member] Nonperforming Financing Receivable [Member]	Dec. 31, 2011 Residential Mortgage, Loans Held For Sale [Member] Nonperforming Financing Receivable [Member]	Sep. 30, 2012 Brokered Deposits Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2011 Brokered Deposits Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2012 Brokered Deposits Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2011 Brokered Deposits Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2012 Long-term Debt [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2011 Long-term Debt [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2012 Long-term Debt [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2011 Long-term Debt [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2012 Repossessed Personal Property [Member] Other Assets [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2011 Repossessed Personal Property [Member] Other Assets [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2012 Repossessed Personal Property [Member] Other Assets [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2011 Repossessed Personal Property [Member] Other Assets [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2012 Fair Value, Measurements, Recurring [Member]	Dec. 31, 2011 Fair Value, Measurements, Recurring [Member]	Sep. 30, 2012 Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2011 Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 3 [Member]	Sep. 30, 2012 Fair Value, Measurements, Recurring [Member] Other real estate owned residential properties [Member] Fair Value, Inputs, Level 3 [Member] Lower Limit	Sep. 30, 2012 Fair Value, Measurements, Recurring [Member] Other real estate owned residential properties [Member] Fair Value, Inputs, Level 3 [Member] Upper Limit	Sep. 30, 2012 Fair Value, Measurements, Recurring [Member] Other real estate owned residential properties [Member] Fair Value, Inputs, Level 3 [Member] Weighted Average [Member]	Sep. 30, 2012 Fair Value, Measurements, Recurring [Member] Other real estate owned commercial properties [Member] Fair Value, Inputs, Level 3 [Member] Lower Limit	Sep. 30, 2012 Fair Value, Measurements, Recurring [Member] Other real estate owned commercial properties [Member] Fair Value, Inputs, Level 3 [Member] Upper Limit	Sep. 30, 2012 Fair Value, Measurements, Recurring [Member] Other real estate owned commercial properties [Member] Fair Value, Inputs, Level 3 [Member] Weighted Average [Member]
Transferred Out of Level 3 in The Fair Value Hierarchy															$ (269,000,000)	$ (95,000,000)	$ (659,000,000)	$ (149,000,000)
Government guaranteed percent																						97.00%
Derivative in a liability position, fair value																							189,000,000
LHFI at fair value	390,000,000	[1]		390,000,000	[1]		433,000,000	[1]					1,900,000,000	1,700,000,000
Trading loans were outstanding																								251,000,000	323,000,000
Recognized losses due to changes in fair value attributable to borrower-specific credit risk																										5,000,000	(4,000,000)	7,000,000	(14,000,000)
Loans held for investment																																															390,000,000	433,000,000	390,000,000	433,000,000
Recognized gains (losses) on liabilities due to changes in its own credit spread																																			(5,000,000)	13,000,000	(11,000,000)	1,000,000	(48,000,000)	57,000,000	(54,000,000)	43,000,000
Issued securities contained in a consolidated CLO at fair value in order to recognize the nonrecourse nature of these liabilities																			287,000,000																												2,050,000,000	1,997,000,000	0	0
Transfer Of Portfolio Loans And Leases To Held For Sale Net Of Impairment																														16,000,000		563,000,000	57,000,000
Allowance for Loan and Lease Losses, Write-offs	(585,000,000)		(536,000,000)	(1,445,000,000)		(1,714,000,000)																										(171,000,000)	(10,000,000)
Loans sold at carrying value	649,000,000		202,000,000	2,000,000,000		479,000,000																										366,000,000		34,000,000
Gain (Loss) on Sale of Mortgage Loans																																4,000,000
Loans transferred from loans held for sale to loans	3,000,000		7,000,000	34,000,000		53,000,000																								7,000,000	13,000,000
Fair Value Inputs, Discount Rate, Variable Spread																																																			15.00%	55.00%	27.00%	10.00%	35.00%	29.00%
Asset Impairment Charges									0	2,000,000	1,000,000	3,000,000																															1,000,000	0	2,000,000	1,000,000
Fair value measurement with unobservable inputs reconciliation recurring basis asset and liabilities level 3 transfers out of																				$ 32,000,000	$ 71,000,000

[1] 2 Includes loans of consolidated VIEs374 3,322