Certain Transfers of Financial Assets and Variable Interest Entities Portfolio Balances and Delinquency Balances Based on 90 days or more Past Due and Net Charge-Offs Related to Managed Portfolio Loans (Additional Information) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Servicing Assets at Fair Value [Line Items]
Cash Flows Between Transferor and Transferee, Receipts on Transferor's Interest in Transferred Financial Assets, Other	$ 4,000,000	$ 4,000,000
LHFS excluded from managed loans disclosure	3,400,000,000		3,200,000,000
Loans Held For Sale [Member]
Servicing Assets at Fair Value [Line Items]
LHFS Accruing90OrMoreDaysPastDueAndNonaccruingExcludedFromManagedLoanDisclosure	$ 12,000,000		$ 39,000,000