Loans, Allowance for Loan and Lease Losses, and Reserve for Off-Balance Sheet Credit Commitments (Detail 2) (Credit Risk)	3 Months Ended
	Mar. 31, 2015
Covered loans
Concentrations of credit risk
Number of states with largest concentration by loan type	5
Total loans outstanding | Noncovered loans | California
Concentrations of credit risk
Percent of total loans outstanding (as a percent)	73.00%
Total loans outstanding | Noncovered loans | New York
Concentrations of credit risk
Percent of total loans outstanding (as a percent)	9.00%
Total loans outstanding | Noncovered loans | Other states and countries
Concentrations of credit risk
Percent of total loans outstanding (as a percent)	18.00%
Total loans outstanding | Covered loans | California
Concentrations of credit risk
Percent of total loans outstanding (as a percent)	32.00%
Total loans outstanding | Covered loans | Texas
Concentrations of credit risk
Percent of total loans outstanding (as a percent)	12.00%
Total loans outstanding | Covered loans | Nevada
Concentrations of credit risk
Percent of total loans outstanding (as a percent)	6.00%
Total loans outstanding | Covered loans | Ohio
Concentrations of credit risk
Percent of total loans outstanding (as a percent)	6.00%
Total loans outstanding | Covered loans | Arizona
Concentrations of credit risk
Percent of total loans outstanding (as a percent)	6.00%
Total loans outstanding | Covered loans | Other states
Concentrations of credit risk
Percent of total loans outstanding (as a percent)	38.00%