Loans, Allowance for Loan and Lease Losses, and Reserve for Off-Balance Sheet Credit Commitments (Details 2) (USD $) In Billions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
FHLB borrowing facility
Collateral
Company pledged loans as collateral	7.60
Credit Risk | Covered loans
Concentrations of credit risk
Number of states with largest concentration by loan type	5
Total loans outstanding | Credit Risk | Noncovered loans | California
Concentrations of credit risk
Percent of total loans outstanding (as a percent)	73.00%
Total loans outstanding | Credit Risk | Noncovered loans | New York
Concentrations of credit risk
Percent of total loans outstanding (as a percent)	10.00%
Total loans outstanding | Credit Risk | Noncovered loans | Other states and countries
Concentrations of credit risk
Percent of total loans outstanding (as a percent)	17.00%
Total loans outstanding | Credit Risk | Covered loans | California
Concentrations of credit risk
Percent of total loans outstanding (as a percent)	32.00%
Total loans outstanding | Credit Risk | Covered loans | Texas
Concentrations of credit risk
Percent of total loans outstanding (as a percent)	12.00%
Total loans outstanding | Credit Risk | Covered loans | Nevada
Concentrations of credit risk
Percent of total loans outstanding (as a percent)	7.00%
Total loans outstanding | Credit Risk | Covered loans | Ohio
Concentrations of credit risk
Percent of total loans outstanding (as a percent)	6.00%
Total loans outstanding | Credit Risk | Covered loans | Arizona
Concentrations of credit risk
Percent of total loans outstanding (as a percent)	6.00%
Total loans outstanding | Credit Risk | Covered loans | Other states
Concentrations of credit risk
Percent of total loans outstanding (as a percent)	37.00%