Fair Values of Assets and Liabilities (Significant Unobservable Level 3 Inputs) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Fair Value, Inputs, Level 3 | Residential mortgage loans | Fair value, recurring
Quantitative information about level 3 fair value measurements
Residential mortgage loans	$ 67
Fair Value, Inputs, Level 3 | IRLCs, net | Fair value, recurring
Quantitative information about level 3 fair value measurements
Derivative instruments	18
Fair Value, Inputs, Level 3 | Stock warrants associated with the sale of the processing business | Fair value, recurring
Quantitative information about level 3 fair value measurements
Derivative instruments	157
Fair Value, Inputs, Level 3 | Swap associated with the sale of Visa, Inc. Class B shares | Fair value, recurring
Quantitative information about level 3 fair value measurements
Derivative instruments	(22)
Fair Value, Inputs, Level 3 | Commercial Loans Held For Sale | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Fair value measurements nonrecurring assets	2
Fair Value, Inputs, Level 3 | OREO Property | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Fair value measurements nonrecurring assets	120
Fair Value, Inputs, Level 3 | Commercial and Industrial Loans | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Fair value measurements nonrecurring assets	69
Fair Value, Inputs, Level 3 | Commercial Mortgage Loans | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Default rates	100.00%
Fair value measurements nonrecurring assets	81
Fair Value, Inputs, Level 3 | Commercial Construction Loans | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Default rates	100.00%
Fair value measurements nonrecurring assets	37
Fair Value, Inputs, Level 3 | Mortgage Servicing Rights | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Fair value measurements nonrecurring assets	$ 767
Minimum | Stock warrants associated with the sale of the processing business | Fair value, recurring
Quantitative information about level 3 fair value measurements
Risk free rate	0.40%
Minimum | Fair Value, Inputs, Level 3 | Residential mortgage loans | Fair value, recurring
Quantitative information about level 3 fair value measurements
Interest rate risk factor	(88.30%)
Credit risk factor	2.30%
Minimum | Fair Value, Inputs, Level 3 | IRLCs, net | Fair value, recurring
Quantitative information about level 3 fair value measurements
Loan closing rates	9.90%
Minimum | Fair Value, Inputs, Level 3 | Stock warrants associated with the sale of the processing business | Fair value, recurring
Quantitative information about level 3 fair value measurements
Expected term (years)	2.0
Expected volatility	29.30%	[1]
Minimum | Fair Value, Inputs, Level 3 | Swap associated with the sale of Visa, Inc. Class B shares | Fair value, recurring
Quantitative information about level 3 fair value measurements
Timing of the resolution of the covered litigation	12/31/2013
Minimum | Fair Value, Inputs, Level 3 | Commercial and Industrial Loans | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Loss severities	0.00%
Minimum | Fair Value, Inputs, Level 3 | Commercial Mortgage Loans | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Loss severities	0.00%
Minimum | Fair Value, Inputs, Level 3 | Commercial Construction Loans | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Loss severities	0.00%
Minimum | Fair Value, Inputs, Level 3 | Mortgage Servicing Rights | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Prepayment speed	0.00%
Discount rate	9.40%
Maximum | Fair Value, Inputs, Level 3 | Residential mortgage loans | Fair value, recurring
Quantitative information about level 3 fair value measurements
Interest rate risk factor	16.30%
Credit risk factor	61.10%
Maximum | Fair Value, Inputs, Level 3 | IRLCs, net | Fair value, recurring
Quantitative information about level 3 fair value measurements
Loan closing rates	87.00%
Maximum | Fair Value, Inputs, Level 3 | Stock warrants associated with the sale of the processing business | Fair value, recurring
Quantitative information about level 3 fair value measurements
Expected term (years)	17.3
Expected volatility	41.70%	[1]
Risk free rate	3.30%
Maximum | Fair Value, Inputs, Level 3 | Swap associated with the sale of Visa, Inc. Class B shares | Fair value, recurring
Quantitative information about level 3 fair value measurements
Timing of the resolution of the covered litigation	12/31/2016
Maximum | Fair Value, Inputs, Level 3 | Commercial and Industrial Loans | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Default rates	100.00%
Loss severities	84.20%
Maximum | Fair Value, Inputs, Level 3 | Commercial Mortgage Loans | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Loss severities	100.00%
Maximum | Fair Value, Inputs, Level 3 | Commercial Construction Loans | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Loss severities	100.00%
Maximum | Fair Value, Inputs, Level 3 | Mortgage Servicing Rights | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Prepayment speed	100.00%
Discount rate	18.00%
Weighted average | Fair Value, Inputs, Level 3 | Residential mortgage loans | Fair value, recurring
Quantitative information about level 3 fair value measurements
Interest rate risk factor	5.20%
Credit risk factor	4.50%
Weighted average | Fair Value, Inputs, Level 3 | IRLCs, net | Fair value, recurring
Quantitative information about level 3 fair value measurements
Loan closing rates	56.50%
Weighted average | Fair Value, Inputs, Level 3 | Stock warrants associated with the sale of the processing business | Fair value, recurring
Quantitative information about level 3 fair value measurements
Expected term (years)	5.0
Expected volatility	35.50%	[1]
Risk free rate	0.10%
Weighted average | Fair Value, Inputs, Level 3 | Commercial Loans Held For Sale | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Cost to sell	10.00%
Weighted average | Fair Value, Inputs, Level 3 | OREO Property | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Cost to sell	10.00%
Weighted average | Fair Value, Inputs, Level 3 | Commercial and Industrial Loans | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Loss severities	15.80%
Weighted average | Fair Value, Inputs, Level 3 | Commercial Mortgage Loans | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Loss severities	23.30%
Weighted average | Fair Value, Inputs, Level 3 | Commercial Construction Loans | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Loss severities	40.90%
Fixed | Fair Value, Inputs, Level 3 | Mortgage Servicing Rights | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Prepayment speed	14.40%
Discount rate	10.60%
Adjustable | Fair Value, Inputs, Level 3 | Mortgage Servicing Rights | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Prepayment speed	26.50%
Discount rate	11.80%

[1] Based on historical and implied volatilities of comparable companies assuming similar expected terms.