Asset Quality - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2014 SecurityLoan	Mar. 31, 2013 SecurityLoan	Dec. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Estimated gross contractual amount receivable of PCI loans	$ 41,000,000
Estimated cash flows nonaccretable amount	11,000,000
Estimated cash flows accretable amount	5,000,000
Purchased Credit Impaired, Outstanding	16,000,000	22,000,000	16,000,000
Accretable yield	5,000,000
Percentage of carrying amount of our commercial nonperforming loans outstanding	53.00%
Percentage of nonperforming loans outstanding face value	70.00%
Percentage of loans held for sale and other nonperforming assets	68.00%
Aggregate carrying amount of largest nonperforming loans		194,000,000
Number of largest nonperforming loans	20	20
Total loans on nonperforming status from continuing operations	75,000,000
Percentage of total loans on nonperforming status	17.00%	30.00%
Net reduction to interest income	4,000,000		23,000,000
Interest income recognized on outstanding balances	2,000,000	2,000,000
Total restructured loans	294,000,000	294,000,000	338,000,000
Addition in restructured loans	30,000,000
Restructured loans partially in payments and charge-offs	74,000,000
Total current loan	54,600,000,000
Percent of total current loan	98.50%
Total past due loan	805,000,000	1,101,000,000	897,000,000
Percent of total past due loans	1.50%
Minimum outstanding impaired commercial loans	2,500,000
Number of days to designate commercial loans will be charged off in full or charged down to the fair value of the underlying collateral payment due period	180 days
Number of days to designate the charge-off policy for most consumer loans taking effect, payment due period	120 days
Number of days to designate home equity and residential mortgage loans to get charged down to the fair value of the underlying collateral payment due period	180 days
Number of days to designate the charge-off policy for credit card loans taking effect, payment due period	180 days
ALLL	834,000,000	893,000,000	848,000,000
ALLL percentage	1.50%	1.70%
ALLL of nonperforming loans percentage	185.70%	137.40%
Increase (decrease) in allowance for loan losses	59,000,000
Percentage decrease in allowance for loan losses	6.60%
Individually evaluated for impairment, corresponding allowance	304,000,000	445,000,000	358,000,000
Corresponding allowance	34,000,000	34,000,000	42,000,000
Collectively Evaluated for Impairment, Outstanding	55,125,000,000	52,107,000,000	54,083,000,000
Collectively evaluated for current, corresponding allowance	799,000,000
Provision (credit) for loan and lease losses	6,000,000	55,000,000
Increase (decrease) liability for credit losses on lending related commitments		3,000,000
Percentage of total allowance for credit losses	1.57%	1.76%
Liability for credit losses on lending-related commitments	35,000,000	32,000,000	37,000,000	29,000,000
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Changes in the accretable yield, accretion	1,000,000
Changes in the accretable yield, net reclassifications	1,000,000
Consumer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nature of default in repayment of loan TDRs	More than 60 days past due
Number of loans	157	240
Financial receivable, modifications, subsequent default, recorded investment	4,000,000	14,000,000
Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nature of default in repayment of loan TDRs	90 days past due
Number of loans	2
Financial receivable, modifications, subsequent default, recorded investment	11,000,000
PCI Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased Credit Impaired, Outstanding	23,000,000
Purchased credit impaired loans carrying value	16,000,000
Purchase Credit Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Corresponding allowance	1,000,000
Collectively Evaluated for Impairment, Outstanding	16,000,000
Provision (credit) for loan and lease losses	$ 0