Fair Values of Assets and Liabilities (Significant Unobservable Level 3 Inputs) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Commercial Loans Held For Sale | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Fair value measurements nonrecurring assets	$ 4		$ 2
Commercial and Industrial Loans | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Default rates	100.00%		100.00%
Fair value measurements nonrecurring assets	20		69
Commercial Mortgage Loans | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Default rates	100.00%		100.00%
Fair value measurements nonrecurring assets	34		81
Commercial Construction Loans | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Default rates	100.00%		100.00%
Fair value measurements nonrecurring assets	7		37
Servicing Rights | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Fair value measurements nonrecurring assets	766		767
OREO Property | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Fair value measurements nonrecurring assets	120		120
Residential mortgage loans | Fair value, recurring
Quantitative information about level 3 fair value measurements
Residential mortgage loans	81		67
IRLCs, net | Fair value, recurring
Quantitative information about level 3 fair value measurements
Derivative instruments	50		18
Stock warrants associated with the sale of the processing business | Fair value, recurring
Quantitative information about level 3 fair value measurements
Derivative instruments	211		157
Swap associated with the sale of Visa, Inc. Class B shares | Fair value, recurring
Quantitative information about level 3 fair value measurements
Derivative instruments	$ (37)		$ (22)
Minimum | Servicing Rights | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Prepayment speed	0.00%		0.00%
Discount rate	9.40%		9.40%
Minimum | Residential mortgage loans | Fair value, recurring
Quantitative information about level 3 fair value measurements
Interest rate risk factor	(91.00%)		(88.30%)
Credit risk factor	0.00%		2.30%
Minimum | IRLCs, net | Fair value, recurring
Quantitative information about level 3 fair value measurements
Loan closing rates	9.90%		9.90%
Minimum | 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 years		2 years
Expected volatility	23.60%	[1]	29.30%	[1]
Minimum | 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	3/31/2014		12/31/2013
Maximum | Servicing Rights | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Prepayment speed	100.00%		100.00%
Discount rate	18.00%		18.00%
Maximum | Residential mortgage loans | Fair value, recurring
Quantitative information about level 3 fair value measurements
Interest rate risk factor	49.00%		16.30%
Credit risk factor	68.40%		61.10%
Maximum | IRLCs, net | Fair value, recurring
Quantitative information about level 3 fair value measurements
Loan closing rates	95.00%		87.00%
Maximum | Stock warrants associated with the sale of the processing business | Fair value, recurring
Quantitative information about level 3 fair value measurements
Expected term (years)	16 years 6 months		17 years 3 months 18 days
Expected volatility	35.00%	[1]	41.70%	[1]
Maximum | 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	3/31/2017		12/31/2016
Weighted average | Commercial Loans Held For Sale | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Cost to sell	10.00%		10.00%
Weighted average | Residential mortgage loans | Fair value, recurring
Quantitative information about level 3 fair value measurements
Interest rate risk factor	6.00%		5.20%
Credit risk factor	3.40%		4.50%
Weighted average | IRLCs, net | Fair value, recurring
Quantitative information about level 3 fair value measurements
Loan closing rates	65.80%		56.50%
Weighted average | 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 years 1 month 6 days		5 years 1 month 3 days
Expected volatility	28.90%	[1]	35.50%	[1]
Fixed | Servicing Rights | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Prepayment speed	14.00%		14.40%
Discount rate	10.50%		10.60%
Adjustable | Servicing Rights | Fair value, nonrecurring
Quantitative information about level 3 fair value measurements
Prepayment speed	26.80%		26.50%
Discount rate	11.70%		11.80%

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